

<!--XBRL Document Created with Wdesk from Workiva-->
<!-- -->
<link:linkbase xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd" xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
  <link:roleRef roleURI="http://www.oesx.com/role/AccountsReceivableNet" xlink:href="oesx-20180630.xsd#AccountsReceivableNet" xlink:type="simple" />
  <link:roleRef roleURI="http://www.oesx.com/role/AccountsReceivableNetDetails" xlink:href="oesx-20180630.xsd#AccountsReceivableNetDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.oesx.com/role/AccountsReceivableNetTables" xlink:href="oesx-20180630.xsd#AccountsReceivableNetTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.oesx.com/role/AccruedExpensesAndOther" xlink:href="oesx-20180630.xsd#AccruedExpensesAndOther" xlink:type="simple" />
  <link:roleRef roleURI="http://www.oesx.com/role/AccruedExpensesAndOtherAccruedExpensesAndOtherDetails" xlink:href="oesx-20180630.xsd#AccruedExpensesAndOtherAccruedExpensesAndOtherDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.oesx.com/role/AccruedExpensesAndOtherNarrativeDetails" xlink:href="oesx-20180630.xsd#AccruedExpensesAndOtherNarrativeDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.oesx.com/role/AccruedExpensesAndOtherTables" xlink:href="oesx-20180630.xsd#AccruedExpensesAndOtherTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.oesx.com/role/AccruedExpensesAndOtherWarrantyAccrualDetails" xlink:href="oesx-20180630.xsd#AccruedExpensesAndOtherWarrantyAccrualDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.oesx.com/role/CommitmentsAndContingencies" xlink:href="oesx-20180630.xsd#CommitmentsAndContingencies" xlink:type="simple" />
  <link:roleRef roleURI="http://www.oesx.com/role/CommitmentsAndContingenciesDetails" xlink:href="oesx-20180630.xsd#CommitmentsAndContingenciesDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.oesx.com/role/DescriptionOfBusiness" xlink:href="oesx-20180630.xsd#DescriptionOfBusiness" xlink:type="simple" />
  <link:roleRef roleURI="http://www.oesx.com/role/DocumentAndEntityInformation" xlink:href="oesx-20180630.xsd#DocumentAndEntityInformation" xlink:type="simple" />
  <link:roleRef roleURI="http://www.oesx.com/role/IncomeTaxes" xlink:href="oesx-20180630.xsd#IncomeTaxes" xlink:type="simple" />
  <link:roleRef roleURI="http://www.oesx.com/role/IncomeTaxesDetails" xlink:href="oesx-20180630.xsd#IncomeTaxesDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.oesx.com/role/IntangibleAssetsNet" xlink:href="oesx-20180630.xsd#IntangibleAssetsNet" xlink:type="simple" />
  <link:roleRef roleURI="http://www.oesx.com/role/IntangibleAssetsNetComponentsAndChangesInOtherIntangibleAssetsDetails" xlink:href="oesx-20180630.xsd#IntangibleAssetsNetComponentsAndChangesInOtherIntangibleAssetsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.oesx.com/role/IntangibleAssetsNetFutureAmortizationByFiscalYearDetails" xlink:href="oesx-20180630.xsd#IntangibleAssetsNetFutureAmortizationByFiscalYearDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.oesx.com/role/IntangibleAssetsNetNarrativeDetails" xlink:href="oesx-20180630.xsd#IntangibleAssetsNetNarrativeDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.oesx.com/role/IntangibleAssetsNetTables" xlink:href="oesx-20180630.xsd#IntangibleAssetsNetTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.oesx.com/role/InventoriesNet" xlink:href="oesx-20180630.xsd#InventoriesNet" xlink:type="simple" />
  <link:roleRef roleURI="http://www.oesx.com/role/InventoriesNetDetails" xlink:href="oesx-20180630.xsd#InventoriesNetDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.oesx.com/role/InventoriesNetTables" xlink:href="oesx-20180630.xsd#InventoriesNetTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.oesx.com/role/LongTermDebt" xlink:href="oesx-20180630.xsd#LongTermDebt" xlink:type="simple" />
  <link:roleRef roleURI="http://www.oesx.com/role/LongTermDebtNarrativeDetails" xlink:href="oesx-20180630.xsd#LongTermDebtNarrativeDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.oesx.com/role/LongTermDebtSummaryOfLongTermDebtDetails" xlink:href="oesx-20180630.xsd#LongTermDebtSummaryOfLongTermDebtDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.oesx.com/role/LongTermDebtTables" xlink:href="oesx-20180630.xsd#LongTermDebtTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.oesx.com/role/NetLossPerCommonShare" xlink:href="oesx-20180630.xsd#NetLossPerCommonShare" xlink:type="simple" />
  <link:roleRef roleURI="http://www.oesx.com/role/NetLossPerCommonShareEarningsPerShareDetails" xlink:href="oesx-20180630.xsd#NetLossPerCommonShareEarningsPerShareDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.oesx.com/role/NetLossPerCommonSharePotentiallyDilutiveSecuritiesDetails" xlink:href="oesx-20180630.xsd#NetLossPerCommonSharePotentiallyDilutiveSecuritiesDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.oesx.com/role/NetLossPerCommonShareTables" xlink:href="oesx-20180630.xsd#NetLossPerCommonShareTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.oesx.com/role/PrepaidExpensesAndOtherCurrentAssets" xlink:href="oesx-20180630.xsd#PrepaidExpensesAndOtherCurrentAssets" xlink:type="simple" />
  <link:roleRef roleURI="http://www.oesx.com/role/PrepaidExpensesAndOtherCurrentAssetsDetails" xlink:href="oesx-20180630.xsd#PrepaidExpensesAndOtherCurrentAssetsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.oesx.com/role/PrepaidExpensesAndOtherCurrentAssetsTables" xlink:href="oesx-20180630.xsd#PrepaidExpensesAndOtherCurrentAssetsTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.oesx.com/role/PropertyAndEquipmentNet" xlink:href="oesx-20180630.xsd#PropertyAndEquipmentNet" xlink:type="simple" />
  <link:roleRef roleURI="http://www.oesx.com/role/PropertyAndEquipmentNetEquipmentUnderCapitalLeasesDetails" xlink:href="oesx-20180630.xsd#PropertyAndEquipmentNetEquipmentUnderCapitalLeasesDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.oesx.com/role/PropertyAndEquipmentNetNarrativeDetails" xlink:href="oesx-20180630.xsd#PropertyAndEquipmentNetNarrativeDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.oesx.com/role/PropertyAndEquipmentNetSummaryOfPropertyAndEquipmentDetails" xlink:href="oesx-20180630.xsd#PropertyAndEquipmentNetSummaryOfPropertyAndEquipmentDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.oesx.com/role/PropertyAndEquipmentNetTables" xlink:href="oesx-20180630.xsd#PropertyAndEquipmentNetTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.oesx.com/role/RelatedPartyTransactions" xlink:href="oesx-20180630.xsd#RelatedPartyTransactions" xlink:type="simple" />
  <link:roleRef roleURI="http://www.oesx.com/role/RelatedPartyTransactionsDetails" xlink:href="oesx-20180630.xsd#RelatedPartyTransactionsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.oesx.com/role/ReorganizationOfBusiness" xlink:href="oesx-20180630.xsd#ReorganizationOfBusiness" xlink:type="simple" />
  <link:roleRef roleURI="http://www.oesx.com/role/ReorganizationOfBusinessNarrativeDetails" xlink:href="oesx-20180630.xsd#ReorganizationOfBusinessNarrativeDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.oesx.com/role/ReorganizationOfBusinessRestructuringBySegmentDetails" xlink:href="oesx-20180630.xsd#ReorganizationOfBusinessRestructuringBySegmentDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.oesx.com/role/ReorganizationOfBusinessRestructuringByStatementOfOperationsLocationDetails" xlink:href="oesx-20180630.xsd#ReorganizationOfBusinessRestructuringByStatementOfOperationsLocationDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.oesx.com/role/ReorganizationOfBusinessTables" xlink:href="oesx-20180630.xsd#ReorganizationOfBusinessTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.oesx.com/role/RevenueDisaggregationOfRevenueDetails" xlink:href="oesx-20180630.xsd#RevenueDisaggregationOfRevenueDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.oesx.com/role/RevenueFinancialStatementImpactOfAdoptingAsc606Details" xlink:href="oesx-20180630.xsd#RevenueFinancialStatementImpactOfAdoptingAsc606Details" xlink:type="simple" />
  <link:roleRef roleURI="http://www.oesx.com/role/RevenueNarrativeDetails" xlink:href="oesx-20180630.xsd#RevenueNarrativeDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.oesx.com/role/RevenueNotes" xlink:href="oesx-20180630.xsd#RevenueNotes" xlink:type="simple" />
  <link:roleRef roleURI="http://www.oesx.com/role/RevenueSummaryOfContractAssetsAndLiabilitiesDetails" xlink:href="oesx-20180630.xsd#RevenueSummaryOfContractAssetsAndLiabilitiesDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.oesx.com/role/RevenueTables" xlink:href="oesx-20180630.xsd#RevenueTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.oesx.com/role/Segments" xlink:href="oesx-20180630.xsd#Segments" xlink:type="simple" />
  <link:roleRef roleURI="http://www.oesx.com/role/SegmentsDetails" xlink:href="oesx-20180630.xsd#SegmentsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.oesx.com/role/SegmentsTables" xlink:href="oesx-20180630.xsd#SegmentsTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.oesx.com/role/ShareholdersEquity" xlink:href="oesx-20180630.xsd#ShareholdersEquity" xlink:type="simple" />
  <link:roleRef roleURI="http://www.oesx.com/role/ShareholdersEquityDetails" xlink:href="oesx-20180630.xsd#ShareholdersEquityDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.oesx.com/role/StockOptionsAndRestrictedShares" xlink:href="oesx-20180630.xsd#StockOptionsAndRestrictedShares" xlink:type="simple" />
  <link:roleRef roleURI="http://www.oesx.com/role/StockOptionsAndRestrictedSharesNarrativeDetails" xlink:href="oesx-20180630.xsd#StockOptionsAndRestrictedSharesNarrativeDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.oesx.com/role/StockOptionsAndRestrictedSharesRestrictedSharesAndStockOptionsDetails" xlink:href="oesx-20180630.xsd#StockOptionsAndRestrictedSharesRestrictedSharesAndStockOptionsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.oesx.com/role/StockOptionsAndRestrictedSharesStockBasedCompensationDetails" xlink:href="oesx-20180630.xsd#StockOptionsAndRestrictedSharesStockBasedCompensationDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.oesx.com/role/StockOptionsAndRestrictedSharesTables" xlink:href="oesx-20180630.xsd#StockOptionsAndRestrictedSharesTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.oesx.com/role/SubsequentEvents" xlink:href="oesx-20180630.xsd#SubsequentEvents" xlink:type="simple" />
  <link:roleRef roleURI="http://www.oesx.com/role/SummaryOfSignificantAccountingPolicies" xlink:href="oesx-20180630.xsd#SummaryOfSignificantAccountingPolicies" xlink:type="simple" />
  <link:roleRef roleURI="http://www.oesx.com/role/SummaryOfSignificantAccountingPoliciesDetails" xlink:href="oesx-20180630.xsd#SummaryOfSignificantAccountingPoliciesDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.oesx.com/role/SummaryOfSignificantAccountingPoliciesPolicies" xlink:href="oesx-20180630.xsd#SummaryOfSignificantAccountingPoliciesPolicies" xlink:type="simple" />
  <link:roleRef roleURI="http://www.oesx.com/role/UnauditedCondensedConsolidatedBalanceSheets" xlink:href="oesx-20180630.xsd#UnauditedCondensedConsolidatedBalanceSheets" xlink:type="simple" />
  <link:roleRef roleURI="http://www.oesx.com/role/UnauditedCondensedConsolidatedBalanceSheetsParenthetical" xlink:href="oesx-20180630.xsd#UnauditedCondensedConsolidatedBalanceSheetsParenthetical" xlink:type="simple" />
  <link:roleRef roleURI="http://www.oesx.com/role/UnauditedCondensedConsolidatedStatementsOfCashFlows" xlink:href="oesx-20180630.xsd#UnauditedCondensedConsolidatedStatementsOfCashFlows" xlink:type="simple" />
  <link:roleRef roleURI="http://www.oesx.com/role/UnauditedCondensedConsolidatedStatementsOfOperations" xlink:href="oesx-20180630.xsd#UnauditedCondensedConsolidatedStatementsOfOperations" xlink:type="simple" />
  <link:roleRef roleURI="http://www.xbrl.org/2009/role/negatedLabel" xlink:href="http://www.xbrl.org/lrr/role/negated-2009-12-16.xsd#negatedLabel" xlink:type="simple" />
  <link:roleRef roleURI="http://www.xbrl.org/2009/role/negatedNetLabel" xlink:href="http://www.xbrl.org/lrr/role/negated-2009-12-16.xsd#negatedNetLabel" xlink:type="simple" />
  <link:roleRef roleURI="http://www.xbrl.org/2009/role/negatedPeriodEndLabel" xlink:href="http://www.xbrl.org/lrr/role/negated-2009-12-16.xsd#negatedPeriodEndLabel" xlink:type="simple" />
  <link:roleRef roleURI="http://www.xbrl.org/2009/role/negatedPeriodStartLabel" xlink:href="http://www.xbrl.org/lrr/role/negated-2009-12-16.xsd#negatedPeriodStartLabel" xlink:type="simple" />
  <link:roleRef roleURI="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:href="http://www.xbrl.org/lrr/role/negated-2009-12-16.xsd#negatedTerseLabel" xlink:type="simple" />
  <link:roleRef roleURI="http://www.xbrl.org/2009/role/negatedTotalLabel" xlink:href="http://www.xbrl.org/lrr/role/negated-2009-12-16.xsd#negatedTotalLabel" xlink:type="simple" />
  <link:roleRef roleURI="http://www.xbrl.org/2009/role/netLabel" xlink:href="http://www.xbrl.org/lrr/role/net-2009-12-16.xsd#netLabel" xlink:type="simple" />
  <link:presentationLink xlink:role="http://www.oesx.com/role/AccountsReceivableNet" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ReceivablesAbstract" xlink:label="loc_us-gaap_ReceivablesAbstract_EBA86BF1B7789B0D9F41CEEC131CC27C" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LoansNotesTradeAndOtherReceivablesDisclosureTextBlock" xlink:label="loc_us-gaap_LoansNotesTradeAndOtherReceivablesDisclosureTextBlock_A9DCDD16101AD99A3F61CEEC131C456A" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ReceivablesAbstract_EBA86BF1B7789B0D9F41CEEC131CC27C" xlink:to="loc_us-gaap_LoansNotesTradeAndOtherReceivablesDisclosureTextBlock_A9DCDD16101AD99A3F61CEEC131C456A" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.oesx.com/role/AccountsReceivableNetDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ReceivablesAbstract" xlink:label="loc_us-gaap_ReceivablesAbstract_C879C2E489085233C5CDCEEC1311B65D" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AccountsReceivableGrossCurrent" xlink:label="loc_us-gaap_AccountsReceivableGrossCurrent_7581B832D746B301CAEACEEC13115ACD" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ReceivablesAbstract_C879C2E489085233C5CDCEEC1311B65D" xlink:to="loc_us-gaap_AccountsReceivableGrossCurrent_7581B832D746B301CAEACEEC13115ACD" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AllowanceForDoubtfulAccountsReceivableCurrent" xlink:label="loc_us-gaap_AllowanceForDoubtfulAccountsReceivableCurrent_C114067D20A91BB4246CCEEC131150B7" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ReceivablesAbstract_C879C2E489085233C5CDCEEC1311B65D" xlink:to="loc_us-gaap_AllowanceForDoubtfulAccountsReceivableCurrent_C114067D20A91BB4246CCEEC131150B7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AccountsReceivableNetCurrent" xlink:label="loc_us-gaap_AccountsReceivableNetCurrent_18DFB543DA576223A8AECEEC13110A64" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ReceivablesAbstract_C879C2E489085233C5CDCEEC1311B65D" xlink:to="loc_us-gaap_AccountsReceivableNetCurrent_18DFB543DA576223A8AECEEC13110A64" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.oesx.com/role/AccountsReceivableNetTables" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ReceivablesAbstract" xlink:label="loc_us-gaap_ReceivablesAbstract_DA403174CB5E118976C2CEEC131420BB" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTextBlock" xlink:label="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTextBlock_64249C72A75CB5B0641ACEEC1314CAFB" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ReceivablesAbstract_DA403174CB5E118976C2CEEC131420BB" xlink:to="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTextBlock_64249C72A75CB5B0641ACEEC1314CAFB" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.oesx.com/role/AccruedExpensesAndOther" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherLiabilitiesDisclosureAbstract" xlink:label="loc_us-gaap_OtherLiabilitiesDisclosureAbstract_0080AE593B93E30BC5F4CEEC125A1469" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AccountsPayableAccruedLiabilitiesAndOtherLiabilitiesDisclosureCurrentTextBlock" xlink:label="loc_us-gaap_AccountsPayableAccruedLiabilitiesAndOtherLiabilitiesDisclosureCurrentTextBlock_E146B3A9307E5BEE81BBCEEC125A7923" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_OtherLiabilitiesDisclosureAbstract_0080AE593B93E30BC5F4CEEC125A1469" xlink:to="loc_us-gaap_AccountsPayableAccruedLiabilitiesAndOtherLiabilitiesDisclosureCurrentTextBlock_E146B3A9307E5BEE81BBCEEC125A7923" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.oesx.com/role/AccruedExpensesAndOtherAccruedExpensesAndOtherDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherLiabilitiesDisclosureAbstract" xlink:label="loc_us-gaap_OtherLiabilitiesDisclosureAbstract_53CC6C2DA09CF024373BCEEC1251970D" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EmployeeRelatedLiabilitiesCurrent" xlink:label="loc_us-gaap_EmployeeRelatedLiabilitiesCurrent_001F523E72CFF3023536CEEC12510DC7" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_OtherLiabilitiesDisclosureAbstract_53CC6C2DA09CF024373BCEEC1251970D" xlink:to="loc_us-gaap_EmployeeRelatedLiabilitiesCurrent_001F523E72CFF3023536CEEC12510DC7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SalesAndExciseTaxPayableCurrent" xlink:label="loc_us-gaap_SalesAndExciseTaxPayableCurrent_4B8CF5CFA1253BCE1E63CEEC1252FED7" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_OtherLiabilitiesDisclosureAbstract_53CC6C2DA09CF024373BCEEC1251970D" xlink:to="loc_us-gaap_SalesAndExciseTaxPayableCurrent_4B8CF5CFA1253BCE1E63CEEC1252FED7" xlink:type="arc" />
    <link:loc xlink:href="oesx-20180630.xsd#oesx_AccruedContractCostsCurrent" xlink:label="loc_oesx_AccruedContractCostsCurrent_C2F35A0C3E55C795B69BCEEC12520B69" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_OtherLiabilitiesDisclosureAbstract_53CC6C2DA09CF024373BCEEC1251970D" xlink:to="loc_oesx_AccruedContractCostsCurrent_C2F35A0C3E55C795B69BCEEC12520B69" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AccruedProfessionalFeesCurrent" xlink:label="loc_us-gaap_AccruedProfessionalFeesCurrent_207E2BADDE6D3AEB08FBCEEC12527885" xlink:type="locator" />
    <link:presentationArc order="4" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_OtherLiabilitiesDisclosureAbstract_53CC6C2DA09CF024373BCEEC1251970D" xlink:to="loc_us-gaap_AccruedProfessionalFeesCurrent_207E2BADDE6D3AEB08FBCEEC12527885" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ProductWarrantyAccrualClassifiedCurrent" xlink:label="loc_us-gaap_ProductWarrantyAccrualClassifiedCurrent_5590F2ABC35E7B818451CEEC1252AA97" xlink:type="locator" />
    <link:presentationArc order="5" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_OtherLiabilitiesDisclosureAbstract_53CC6C2DA09CF024373BCEEC1251970D" xlink:to="loc_us-gaap_ProductWarrantyAccrualClassifiedCurrent_5590F2ABC35E7B818451CEEC1252AA97" xlink:type="arc" />
    <link:loc xlink:href="oesx-20180630.xsd#oesx_SalesReturnsReserve" xlink:label="loc_oesx_SalesReturnsReserve_AEEB75FD412A36A063B6CF25A81AFA08" xlink:type="locator" />
    <link:presentationArc order="6" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_OtherLiabilitiesDisclosureAbstract_53CC6C2DA09CF024373BCEEC1251970D" xlink:to="loc_oesx_SalesReturnsReserve_AEEB75FD412A36A063B6CF25A81AFA08" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DeferredRevenueAndCredits" xlink:label="loc_us-gaap_DeferredRevenueAndCredits_1CCC014F59DD56FADD72CF1BC495E8A8" xlink:type="locator" />
    <link:presentationArc order="7" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_OtherLiabilitiesDisclosureAbstract_53CC6C2DA09CF024373BCEEC1251970D" xlink:to="loc_us-gaap_DeferredRevenueAndCredits_1CCC014F59DD56FADD72CF1BC495E8A8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherAccruedLiabilitiesCurrent" xlink:label="loc_us-gaap_OtherAccruedLiabilitiesCurrent_124005A2BA8A0CABCBAACEEC1252DC1E" xlink:type="locator" />
    <link:presentationArc order="8" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_OtherLiabilitiesDisclosureAbstract_53CC6C2DA09CF024373BCEEC1251970D" xlink:to="loc_us-gaap_OtherAccruedLiabilitiesCurrent_124005A2BA8A0CABCBAACEEC1252DC1E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AccruedLiabilitiesCurrent" xlink:label="loc_us-gaap_AccruedLiabilitiesCurrent_87E016FE39FEAD2BFF47CEEC1253303B" xlink:type="locator" />
    <link:presentationArc order="9" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_OtherLiabilitiesDisclosureAbstract_53CC6C2DA09CF024373BCEEC1251970D" xlink:to="loc_us-gaap_AccruedLiabilitiesCurrent_87E016FE39FEAD2BFF47CEEC1253303B" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.oesx.com/role/AccruedExpensesAndOtherNarrativeDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherLiabilitiesDisclosureAbstract" xlink:label="loc_us-gaap_OtherLiabilitiesDisclosureAbstract_8DD62A88ABEA3406D88BCEEC123FE981" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable" xlink:label="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_7142A26C97F6459929C1CEEC123F2F49" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_OtherLiabilitiesDisclosureAbstract_8DD62A88ABEA3406D88BCEEC123FE981" xlink:to="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_7142A26C97F6459929C1CEEC123F2F49" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RangeAxis" xlink:label="loc_us-gaap_RangeAxis_A50FC6166771D8C25E4CCEEC123FC8C4" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_7142A26C97F6459929C1CEEC123F2F49" xlink:to="loc_us-gaap_RangeAxis_A50FC6166771D8C25E4CCEEC123FC8C4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RangeMember" xlink:label="loc_us-gaap_RangeMember_F8C4D871EF47C45E9CCCCEEC123FA4EB" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_RangeAxis_A50FC6166771D8C25E4CCEEC123FC8C4" xlink:to="loc_us-gaap_RangeMember_F8C4D871EF47C45E9CCCCEEC123FA4EB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_MinimumMember" xlink:label="loc_us-gaap_MinimumMember_A23965B0B98950958B0BCEEC1240B7E4" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_RangeMember_F8C4D871EF47C45E9CCCCEEC123FA4EB" xlink:to="loc_us-gaap_MinimumMember_A23965B0B98950958B0BCEEC1240B7E4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_MaximumMember" xlink:label="loc_us-gaap_MaximumMember_F481D2840781B45CF8A5CEEC12406A92" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_RangeMember_F8C4D871EF47C45E9CCCCEEC123FA4EB" xlink:to="loc_us-gaap_MaximumMember_F481D2840781B45CF8A5CEEC12406A92" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SegmentReportingInformationLineItems" xlink:label="loc_us-gaap_SegmentReportingInformationLineItems_FB4D4AE1C87B0704CC41CEEC124057C4" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_7142A26C97F6459929C1CEEC123F2F49" xlink:to="loc_us-gaap_SegmentReportingInformationLineItems_FB4D4AE1C87B0704CC41CEEC124057C4" xlink:type="arc" />
    <link:loc xlink:href="oesx-20180630.xsd#oesx_LimitedProductWarrantyTerm" xlink:label="loc_oesx_LimitedProductWarrantyTerm_0BD78EC2326CCF8BFCC1CEEC12412827" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_FB4D4AE1C87B0704CC41CEEC124057C4" xlink:to="loc_oesx_LimitedProductWarrantyTerm_0BD78EC2326CCF8BFCC1CEEC12412827" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.oesx.com/role/AccruedExpensesAndOtherTables" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherLiabilitiesDisclosureAbstract" xlink:label="loc_us-gaap_OtherLiabilitiesDisclosureAbstract_55B6A50DA64C591DB2EFCEEC125626CA" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfAccruedLiabilitiesTableTextBlock" xlink:label="loc_us-gaap_ScheduleOfAccruedLiabilitiesTableTextBlock_F136AFE02722BAF45B6ECEEC1256D943" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_OtherLiabilitiesDisclosureAbstract_55B6A50DA64C591DB2EFCEEC125626CA" xlink:to="loc_us-gaap_ScheduleOfAccruedLiabilitiesTableTextBlock_F136AFE02722BAF45B6ECEEC1256D943" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfProductWarrantyLiabilityTableTextBlock" xlink:label="loc_us-gaap_ScheduleOfProductWarrantyLiabilityTableTextBlock_F83AF508456A983888D7CEEC1257D123" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_OtherLiabilitiesDisclosureAbstract_55B6A50DA64C591DB2EFCEEC125626CA" xlink:to="loc_us-gaap_ScheduleOfProductWarrantyLiabilityTableTextBlock_F83AF508456A983888D7CEEC1257D123" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.oesx.com/role/AccruedExpensesAndOtherWarrantyAccrualDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherLiabilitiesDisclosureAbstract" xlink:label="loc_us-gaap_OtherLiabilitiesDisclosureAbstract_F84E9C2BC343BA298C5FF2A6CD7CFD16" xlink:type="locator" />
    <link:loc xlink:href="oesx-20180630.xsd#oesx_StandardAndExtendedProductWarrantyAccrualIncreaseDecreaseReclassificationAdjustment" xlink:label="loc_oesx_StandardAndExtendedProductWarrantyAccrualIncreaseDecreaseReclassificationAdjustment_2B3F98876950FD9B2237F2DCE5F902B0" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_OtherLiabilitiesDisclosureAbstract_F84E9C2BC343BA298C5FF2A6CD7CFD16" xlink:to="loc_oesx_StandardAndExtendedProductWarrantyAccrualIncreaseDecreaseReclassificationAdjustment_2B3F98876950FD9B2237F2DCE5F902B0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_MovementInStandardProductWarrantyAccrualRollForward" xlink:label="loc_us-gaap_MovementInStandardProductWarrantyAccrualRollForward_80FF56BF6C59FC59ABB7F2A6CD7C409D" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_OtherLiabilitiesDisclosureAbstract_F84E9C2BC343BA298C5FF2A6CD7CFD16" xlink:to="loc_us-gaap_MovementInStandardProductWarrantyAccrualRollForward_80FF56BF6C59FC59ABB7F2A6CD7C409D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ProductWarrantyAccrual" xlink:label="loc_us-gaap_ProductWarrantyAccrual_7C708337BDD3D74E4D28F2A6CD7C0B02" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/periodStartLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_MovementInStandardProductWarrantyAccrualRollForward_80FF56BF6C59FC59ABB7F2A6CD7C409D" xlink:to="loc_us-gaap_ProductWarrantyAccrual_7C708337BDD3D74E4D28F2A6CD7C0B02" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ProductWarrantyAccrualPreexistingIncreaseDecrease" xlink:label="loc_us-gaap_ProductWarrantyAccrualPreexistingIncreaseDecrease_4A7542A3356E7337A637F2A6CD7D10AF" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_MovementInStandardProductWarrantyAccrualRollForward_80FF56BF6C59FC59ABB7F2A6CD7C409D" xlink:to="loc_us-gaap_ProductWarrantyAccrualPreexistingIncreaseDecrease_4A7542A3356E7337A637F2A6CD7D10AF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ProductWarrantyAccrualPayments" xlink:label="loc_us-gaap_ProductWarrantyAccrualPayments_D763187A3951393A9266F2A6CD7D9F8C" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_MovementInStandardProductWarrantyAccrualRollForward_80FF56BF6C59FC59ABB7F2A6CD7C409D" xlink:to="loc_us-gaap_ProductWarrantyAccrualPayments_D763187A3951393A9266F2A6CD7D9F8C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ProductWarrantyAccrual" xlink:label="loc_us-gaap_ProductWarrantyAccrual_1A8A70CB5D06E19470CAF2A6CD7DB359" xlink:type="locator" />
    <link:presentationArc order="4" preferredLabel="http://www.xbrl.org/2003/role/periodEndLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_MovementInStandardProductWarrantyAccrualRollForward_80FF56BF6C59FC59ABB7F2A6CD7C409D" xlink:to="loc_us-gaap_ProductWarrantyAccrual_1A8A70CB5D06E19470CAF2A6CD7DB359" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.oesx.com/role/CommitmentsAndContingencies" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CommitmentsAndContingenciesDisclosureAbstract" xlink:label="loc_us-gaap_CommitmentsAndContingenciesDisclosureAbstract_78206D816DEE37009956CEEC11E67840" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CommitmentsAndContingenciesDisclosureTextBlock" xlink:label="loc_us-gaap_CommitmentsAndContingenciesDisclosureTextBlock_2A48D4E22368186A04E7CEEC11E77AC4" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_CommitmentsAndContingenciesDisclosureAbstract_78206D816DEE37009956CEEC11E67840" xlink:to="loc_us-gaap_CommitmentsAndContingenciesDisclosureTextBlock_2A48D4E22368186A04E7CEEC11E77AC4" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.oesx.com/role/CommitmentsAndContingenciesDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CommitmentsAndContingenciesDisclosureAbstract" xlink:label="loc_us-gaap_CommitmentsAndContingenciesDisclosureAbstract_580D2970FFDB23633E4CF2A6CD21FC40" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OperatingLeasesRentExpenseNet" xlink:label="loc_us-gaap_OperatingLeasesRentExpenseNet_1187842C106353365EB1F2A6CD22B691" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_CommitmentsAndContingenciesDisclosureAbstract_580D2970FFDB23633E4CF2A6CD21FC40" xlink:to="loc_us-gaap_OperatingLeasesRentExpenseNet_1187842C106353365EB1F2A6CD22B691" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.oesx.com/role/DescriptionOfBusiness" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract" xlink:label="loc_us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract_2E819B80DFD05028ADE93DE65CFD0393" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsDisclosureTextBlock" xlink:label="loc_us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsDisclosureTextBlock_9068256E911A589D8DDE589ACC68BB92" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract_2E819B80DFD05028ADE93DE65CFD0393" xlink:to="loc_us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsDisclosureTextBlock_9068256E911A589D8DDE589ACC68BB92" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.oesx.com/role/DocumentAndEntityInformation" xlink:type="extended">
    <link:loc xlink:href="oesx-20180630.xsd#oesx_DocumentAndEntityInformationAbstract" xlink:label="loc_oesx_DocumentAndEntityInformationAbstract_DE1D2191CBBF572083E7404D90A677DD" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityRegistrantName" xlink:label="loc_dei_EntityRegistrantName_72F6B41F64D1582D83E07505F7A6395C" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_oesx_DocumentAndEntityInformationAbstract_DE1D2191CBBF572083E7404D90A677DD" xlink:to="loc_dei_EntityRegistrantName_72F6B41F64D1582D83E07505F7A6395C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityCentralIndexKey" xlink:label="loc_dei_EntityCentralIndexKey_64BF781A60265DDEB423B3C224C0E091" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_oesx_DocumentAndEntityInformationAbstract_DE1D2191CBBF572083E7404D90A677DD" xlink:to="loc_dei_EntityCentralIndexKey_64BF781A60265DDEB423B3C224C0E091" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_DocumentType" xlink:label="loc_dei_DocumentType_41797C2EB9E657F3A60A260657983EF7" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_oesx_DocumentAndEntityInformationAbstract_DE1D2191CBBF572083E7404D90A677DD" xlink:to="loc_dei_DocumentType_41797C2EB9E657F3A60A260657983EF7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_DocumentPeriodEndDate" xlink:label="loc_dei_DocumentPeriodEndDate_4BD686C1DEBF54A5B35B873C78ABF0DF" xlink:type="locator" />
    <link:presentationArc order="4" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_oesx_DocumentAndEntityInformationAbstract_DE1D2191CBBF572083E7404D90A677DD" xlink:to="loc_dei_DocumentPeriodEndDate_4BD686C1DEBF54A5B35B873C78ABF0DF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_AmendmentFlag" xlink:label="loc_dei_AmendmentFlag_4E81BD60C09A542981AA4DD871DB7096" xlink:type="locator" />
    <link:presentationArc order="5" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_oesx_DocumentAndEntityInformationAbstract_DE1D2191CBBF572083E7404D90A677DD" xlink:to="loc_dei_AmendmentFlag_4E81BD60C09A542981AA4DD871DB7096" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_DocumentFiscalYearFocus" xlink:label="loc_dei_DocumentFiscalYearFocus_6E23D7AA0DDE5A24990CA6E06A71CF74" xlink:type="locator" />
    <link:presentationArc order="6" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_oesx_DocumentAndEntityInformationAbstract_DE1D2191CBBF572083E7404D90A677DD" xlink:to="loc_dei_DocumentFiscalYearFocus_6E23D7AA0DDE5A24990CA6E06A71CF74" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_DocumentFiscalPeriodFocus" xlink:label="loc_dei_DocumentFiscalPeriodFocus_3ABEEB4C0A92534EA238A1A27F3BBEF7" xlink:type="locator" />
    <link:presentationArc order="7" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_oesx_DocumentAndEntityInformationAbstract_DE1D2191CBBF572083E7404D90A677DD" xlink:to="loc_dei_DocumentFiscalPeriodFocus_3ABEEB4C0A92534EA238A1A27F3BBEF7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_CurrentFiscalYearEndDate" xlink:label="loc_dei_CurrentFiscalYearEndDate_8BC3C38CF7B656398191435F6E7DD674" xlink:type="locator" />
    <link:presentationArc order="8" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_oesx_DocumentAndEntityInformationAbstract_DE1D2191CBBF572083E7404D90A677DD" xlink:to="loc_dei_CurrentFiscalYearEndDate_8BC3C38CF7B656398191435F6E7DD674" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityFilerCategory" xlink:label="loc_dei_EntityFilerCategory_13A52805E32A5EF9848B76FBB05902A3" xlink:type="locator" />
    <link:presentationArc order="9" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_oesx_DocumentAndEntityInformationAbstract_DE1D2191CBBF572083E7404D90A677DD" xlink:to="loc_dei_EntityFilerCategory_13A52805E32A5EF9848B76FBB05902A3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityCommonStockSharesOutstanding" xlink:label="loc_dei_EntityCommonStockSharesOutstanding_39153B7B83E057069851FC934BF3A85C" xlink:type="locator" />
    <link:presentationArc order="10" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_oesx_DocumentAndEntityInformationAbstract_DE1D2191CBBF572083E7404D90A677DD" xlink:to="loc_dei_EntityCommonStockSharesOutstanding_39153B7B83E057069851FC934BF3A85C" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.oesx.com/role/IncomeTaxes" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncomeTaxDisclosureAbstract" xlink:label="loc_us-gaap_IncomeTaxDisclosureAbstract_4120B76CE792C382D0B9CEEC11F1285F" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncomeTaxDisclosureTextBlock" xlink:label="loc_us-gaap_IncomeTaxDisclosureTextBlock_59AB237436C5534CA56ACEEC11F22EA5" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncomeTaxDisclosureAbstract_4120B76CE792C382D0B9CEEC11F1285F" xlink:to="loc_us-gaap_IncomeTaxDisclosureTextBlock_59AB237436C5534CA56ACEEC11F22EA5" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.oesx.com/role/IncomeTaxesDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncomeTaxDisclosureAbstract" xlink:label="loc_us-gaap_IncomeTaxDisclosureAbstract_5EFA704136618957D624CEEC11EBFEDF" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncomeTaxExpenseBenefit" xlink:label="loc_us-gaap_IncomeTaxExpenseBenefit_04D323858500E0D8BC67CF33CFB618F0" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncomeTaxDisclosureAbstract_5EFA704136618957D624CEEC11EBFEDF" xlink:to="loc_us-gaap_IncomeTaxExpenseBenefit_04D323858500E0D8BC67CF33CFB618F0" xlink:type="arc" />
    <link:loc xlink:href="oesx-20180630.xsd#oesx_TaxCutsandJobsActof2017IncompleteAccountingChangeinTaxRateDeferredTaxAssetProvisionalIncomeTaxExpenseBenefit" xlink:label="loc_oesx_TaxCutsandJobsActof2017IncompleteAccountingChangeinTaxRateDeferredTaxAssetProvisionalIncomeTaxExpenseBenefit_25CF4FBC8FDC6944B655CEEC11EEBC40" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncomeTaxDisclosureAbstract_5EFA704136618957D624CEEC11EBFEDF" xlink:to="loc_oesx_TaxCutsandJobsActof2017IncompleteAccountingChangeinTaxRateDeferredTaxAssetProvisionalIncomeTaxExpenseBenefit_25CF4FBC8FDC6944B655CEEC11EEBC40" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_UnrecognizedTaxBenefits" xlink:label="loc_us-gaap_UnrecognizedTaxBenefits_85187F3442C367321330CEEC11EE9C43" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncomeTaxDisclosureAbstract_5EFA704136618957D624CEEC11EBFEDF" xlink:to="loc_us-gaap_UnrecognizedTaxBenefits_85187F3442C367321330CEEC11EE9C43" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.oesx.com/role/IntangibleAssetsNet" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_GoodwillAndIntangibleAssetsDisclosureAbstract" xlink:label="loc_us-gaap_GoodwillAndIntangibleAssetsDisclosureAbstract_456A8310934EB2F55721CEEC128BA771" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_GoodwillAndIntangibleAssetsDisclosureTextBlock" xlink:label="loc_us-gaap_GoodwillAndIntangibleAssetsDisclosureTextBlock_4AE514B5D2512768D805CEEC128B934C" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_GoodwillAndIntangibleAssetsDisclosureAbstract_456A8310934EB2F55721CEEC128BA771" xlink:to="loc_us-gaap_GoodwillAndIntangibleAssetsDisclosureTextBlock_4AE514B5D2512768D805CEEC128B934C" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.oesx.com/role/IntangibleAssetsNetComponentsAndChangesInOtherIntangibleAssetsDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_GoodwillAndIntangibleAssetsDisclosureAbstract" xlink:label="loc_us-gaap_GoodwillAndIntangibleAssetsDisclosureAbstract_81EEC997759AD8E25635CEEC1271C44F" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable" xlink:label="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_4570DB5DF0FF00D941A4CEEC12723C9A" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_GoodwillAndIntangibleAssetsDisclosureAbstract_81EEC997759AD8E25635CEEC1271C44F" xlink:to="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_4570DB5DF0FF00D941A4CEEC12723C9A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_70520F3D75DB3BDF1DCBCEEC12728027" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_4570DB5DF0FF00D941A4CEEC12723C9A" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_70520F3D75DB3BDF1DCBCEEC12728027" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_549D8BD1D23D8A74C370CEEC12720371" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_70520F3D75DB3BDF1DCBCEEC12728027" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_549D8BD1D23D8A74C370CEEC12720371" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PatentsMember" xlink:label="loc_us-gaap_PatentsMember_780D10E734EFC767D9CBCEEC12735B4D" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_549D8BD1D23D8A74C370CEEC12720371" xlink:to="loc_us-gaap_PatentsMember_780D10E734EFC767D9CBCEEC12735B4D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LicensingAgreementsMember" xlink:label="loc_us-gaap_LicensingAgreementsMember_356990B87DFA29751CCFCEEC1273C800" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_549D8BD1D23D8A74C370CEEC12720371" xlink:to="loc_us-gaap_LicensingAgreementsMember_356990B87DFA29751CCFCEEC1273C800" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_TrademarksAndTradeNamesMember" xlink:label="loc_us-gaap_TrademarksAndTradeNamesMember_F26234799CFA01B6BA77CEEC1274873E" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_549D8BD1D23D8A74C370CEEC12720371" xlink:to="loc_us-gaap_TrademarksAndTradeNamesMember_F26234799CFA01B6BA77CEEC1274873E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CustomerRelationshipsMember" xlink:label="loc_us-gaap_CustomerRelationshipsMember_D453FE323F76EC568AAACEEC12749065" xlink:type="locator" />
    <link:presentationArc order="4" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_549D8BD1D23D8A74C370CEEC12720371" xlink:to="loc_us-gaap_CustomerRelationshipsMember_D453FE323F76EC568AAACEEC12749065" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DevelopedTechnologyRightsMember" xlink:label="loc_us-gaap_DevelopedTechnologyRightsMember_EE23CC3C22B1A62F33ACCEEC127C6D71" xlink:type="locator" />
    <link:presentationArc order="5" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_549D8BD1D23D8A74C370CEEC12720371" xlink:to="loc_us-gaap_DevelopedTechnologyRightsMember_EE23CC3C22B1A62F33ACCEEC127C6D71" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NoncompeteAgreementsMember" xlink:label="loc_us-gaap_NoncompeteAgreementsMember_0A85DD3B99315B1C6AAECEEC127DFA17" xlink:type="locator" />
    <link:presentationArc order="6" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_549D8BD1D23D8A74C370CEEC12720371" xlink:to="loc_us-gaap_NoncompeteAgreementsMember_0A85DD3B99315B1C6AAECEEC127DFA17" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsLineItems" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_27F4C0BF36FA6B5B4F91CEEC127D19E0" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_4570DB5DF0FF00D941A4CEEC12723C9A" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_27F4C0BF36FA6B5B4F91CEEC127D19E0" xlink:type="arc" />
    <link:loc xlink:href="oesx-20180630.xsd#oesx_FiniteLivedAndIndefiniteLivedIntangibleAssetsGross" xlink:label="loc_oesx_FiniteLivedAndIndefiniteLivedIntangibleAssetsGross_740060C9B275A0162E0CCEEC127DE206" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_27F4C0BF36FA6B5B4F91CEEC127D19E0" xlink:to="loc_oesx_FiniteLivedAndIndefiniteLivedIntangibleAssetsGross_740060C9B275A0162E0CCEEC127DE206" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_9E75FC2855FBA8C8393DCEEC127D44E3" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_27F4C0BF36FA6B5B4F91CEEC127D19E0" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_9E75FC2855FBA8C8393DCEEC127D44E3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IntangibleAssetsNetExcludingGoodwill" xlink:label="loc_us-gaap_IntangibleAssetsNetExcludingGoodwill_ADD845A2590E12D05987CEEC127E11DA" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_27F4C0BF36FA6B5B4F91CEEC127D19E0" xlink:to="loc_us-gaap_IntangibleAssetsNetExcludingGoodwill_ADD845A2590E12D05987CEEC127E11DA" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.oesx.com/role/IntangibleAssetsNetFutureAmortizationByFiscalYearDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_GoodwillAndIntangibleAssetsDisclosureAbstract" xlink:label="loc_us-gaap_GoodwillAndIntangibleAssetsDisclosureAbstract_5AD2FF59AA32093F5504CEEC12607251" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsFutureAmortizationExpenseAbstract" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsFutureAmortizationExpenseAbstract_7AF60D08D0440ABDBC07CEEC1261CA0D" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_GoodwillAndIntangibleAssetsDisclosureAbstract_5AD2FF59AA32093F5504CEEC12607251" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsFutureAmortizationExpenseAbstract_7AF60D08D0440ABDBC07CEEC1261CA0D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseRemainderOfFiscalYear" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseRemainderOfFiscalYear_C07AF733BEB237877154CEEC12616A62" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsFutureAmortizationExpenseAbstract_7AF60D08D0440ABDBC07CEEC1261CA0D" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseRemainderOfFiscalYear_C07AF733BEB237877154CEEC12616A62" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo_2231FFBAD76B46D94672CEEC1262F5D5" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsFutureAmortizationExpenseAbstract_7AF60D08D0440ABDBC07CEEC1261CA0D" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo_2231FFBAD76B46D94672CEEC1262F5D5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree_1C1F5A07557C2FF08DCBCEEC12623136" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsFutureAmortizationExpenseAbstract_7AF60D08D0440ABDBC07CEEC1261CA0D" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree_1C1F5A07557C2FF08DCBCEEC12623136" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour_0996FF8DFBEA9E90371FCEEC12623963" xlink:type="locator" />
    <link:presentationArc order="4" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsFutureAmortizationExpenseAbstract_7AF60D08D0440ABDBC07CEEC1261CA0D" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour_0996FF8DFBEA9E90371FCEEC12623963" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive_71BACDA10A36DEFA5FCDCEEC12625D6F" xlink:type="locator" />
    <link:presentationArc order="5" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsFutureAmortizationExpenseAbstract_7AF60D08D0440ABDBC07CEEC1261CA0D" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive_71BACDA10A36DEFA5FCDCEEC12625D6F" xlink:type="arc" />
    <link:loc xlink:href="oesx-20180630.xsd#oesx_FiniteLivedIntangibleAssetsAmortizationExpenseYearSix" xlink:label="loc_oesx_FiniteLivedIntangibleAssetsAmortizationExpenseYearSix_F9046ED5509B62E78BB1CEEC1262792B" xlink:type="locator" />
    <link:presentationArc order="6" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsFutureAmortizationExpenseAbstract_7AF60D08D0440ABDBC07CEEC1261CA0D" xlink:to="loc_oesx_FiniteLivedIntangibleAssetsAmortizationExpenseYearSix_F9046ED5509B62E78BB1CEEC1262792B" xlink:type="arc" />
    <link:loc xlink:href="oesx-20180630.xsd#oesx_FiniteLivedIntangibleAssetsAmortizationExpenseAfterYearSix" xlink:label="loc_oesx_FiniteLivedIntangibleAssetsAmortizationExpenseAfterYearSix_8700E962B62DF984F73FCEEC1262A5AB" xlink:type="locator" />
    <link:presentationArc order="7" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsFutureAmortizationExpenseAbstract_7AF60D08D0440ABDBC07CEEC1261CA0D" xlink:to="loc_oesx_FiniteLivedIntangibleAssetsAmortizationExpenseAfterYearSix_8700E962B62DF984F73FCEEC1262A5AB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsNet" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsNet_A7CE2B0CAFBA89E91380CEEC12626A9F" xlink:type="locator" />
    <link:presentationArc order="8" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsFutureAmortizationExpenseAbstract_7AF60D08D0440ABDBC07CEEC1261CA0D" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsNet_A7CE2B0CAFBA89E91380CEEC12626A9F" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.oesx.com/role/IntangibleAssetsNetNarrativeDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_GoodwillAndIntangibleAssetsDisclosureAbstract" xlink:label="loc_us-gaap_GoodwillAndIntangibleAssetsDisclosureAbstract_E0A78654DE0C8590D060CEEC1268287F" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AmortizationOfIntangibleAssets" xlink:label="loc_us-gaap_AmortizationOfIntangibleAssets_C205B8EA9F81620F6325CEEC126867EF" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_GoodwillAndIntangibleAssetsDisclosureAbstract_E0A78654DE0C8590D060CEEC1268287F" xlink:to="loc_us-gaap_AmortizationOfIntangibleAssets_C205B8EA9F81620F6325CEEC126867EF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable" xlink:label="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_7E0602ADE21CB2478D25CEEC12699464" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_GoodwillAndIntangibleAssetsDisclosureAbstract_E0A78654DE0C8590D060CEEC1268287F" xlink:to="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_7E0602ADE21CB2478D25CEEC12699464" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_B0E02B3AF8AF44BA01C8CEEC12695A4F" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_7E0602ADE21CB2478D25CEEC12699464" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_B0E02B3AF8AF44BA01C8CEEC12695A4F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_B0489CAA25F304D06E04CEEC1269251C" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_B0E02B3AF8AF44BA01C8CEEC12695A4F" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_B0489CAA25F304D06E04CEEC1269251C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_TrademarksAndTradeNamesMember" xlink:label="loc_us-gaap_TrademarksAndTradeNamesMember_917E7674B0FFECC4CF44CEEC12696187" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_B0489CAA25F304D06E04CEEC1269251C" xlink:to="loc_us-gaap_TrademarksAndTradeNamesMember_917E7674B0FFECC4CF44CEEC12696187" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RangeAxis" xlink:label="loc_us-gaap_RangeAxis_A19A3EF58827FE5151FACEEC126A6AB6" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_7E0602ADE21CB2478D25CEEC12699464" xlink:to="loc_us-gaap_RangeAxis_A19A3EF58827FE5151FACEEC126A6AB6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RangeMember" xlink:label="loc_us-gaap_RangeMember_7A86B8FE76E51FF6D362CEEC126A952A" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_RangeAxis_A19A3EF58827FE5151FACEEC126A6AB6" xlink:to="loc_us-gaap_RangeMember_7A86B8FE76E51FF6D362CEEC126A952A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_WeightedAverageMember" xlink:label="loc_us-gaap_WeightedAverageMember_1D075404E41297AAA7FDCEEC126A65D4" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_RangeMember_7A86B8FE76E51FF6D362CEEC126A952A" xlink:to="loc_us-gaap_WeightedAverageMember_1D075404E41297AAA7FDCEEC126A65D4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SegmentReportingInformationLineItems" xlink:label="loc_us-gaap_SegmentReportingInformationLineItems_B7EAA7468D1DAB2061FBCEEC126A4733" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_7E0602ADE21CB2478D25CEEC12699464" xlink:to="loc_us-gaap_SegmentReportingInformationLineItems_B7EAA7468D1DAB2061FBCEEC126A4733" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetUsefulLife" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetUsefulLife_838031099682CB050735CEEC126B8516" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_B7EAA7468D1DAB2061FBCEEC126A4733" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetUsefulLife_838031099682CB050735CEEC126B8516" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.oesx.com/role/IntangibleAssetsNetTables" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_GoodwillAndIntangibleAssetsDisclosureAbstract" xlink:label="loc_us-gaap_GoodwillAndIntangibleAssetsDisclosureAbstract_6A357AAB40C19E9B965ACEEC12822CBF" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTableTextBlock" xlink:label="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTableTextBlock_2FA05880AEFF4ACB3230CEEC1282086C" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_GoodwillAndIntangibleAssetsDisclosureAbstract_6A357AAB40C19E9B965ACEEC12822CBF" xlink:to="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTableTextBlock_2FA05880AEFF4ACB3230CEEC1282086C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseTableTextBlock" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseTableTextBlock_0AF50DC5BD5E5AEAABADCEEC1282B85E" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_GoodwillAndIntangibleAssetsDisclosureAbstract_6A357AAB40C19E9B965ACEEC12822CBF" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseTableTextBlock_0AF50DC5BD5E5AEAABADCEEC1282B85E" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.oesx.com/role/InventoriesNet" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_InventoryDisclosureAbstract" xlink:label="loc_us-gaap_InventoryDisclosureAbstract_49A4A1E5557FC07D032ACEEC12EC599B" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_InventoryDisclosureTextBlock" xlink:label="loc_us-gaap_InventoryDisclosureTextBlock_2007CC37F8487A8FD5EBCEEC12EC3A81" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_InventoryDisclosureAbstract_49A4A1E5557FC07D032ACEEC12EC599B" xlink:to="loc_us-gaap_InventoryDisclosureTextBlock_2007CC37F8487A8FD5EBCEEC12EC3A81" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.oesx.com/role/InventoriesNetDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_InventoryDisclosureAbstract" xlink:label="loc_us-gaap_InventoryDisclosureAbstract_09D7B6E2A83E51A676E3CEEC12DB52D2" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_InventoryGrossAbstract" xlink:label="loc_us-gaap_InventoryGrossAbstract_BF76AF58396CB8B48D88CEEC12DBD6F1" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_InventoryDisclosureAbstract_09D7B6E2A83E51A676E3CEEC12DB52D2" xlink:to="loc_us-gaap_InventoryGrossAbstract_BF76AF58396CB8B48D88CEEC12DBD6F1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_InventoryRawMaterialsAndSupplies" xlink:label="loc_us-gaap_InventoryRawMaterialsAndSupplies_FF1B77105D6FE4A6D70FCEEC12DB907C" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_InventoryGrossAbstract_BF76AF58396CB8B48D88CEEC12DBD6F1" xlink:to="loc_us-gaap_InventoryRawMaterialsAndSupplies_FF1B77105D6FE4A6D70FCEEC12DB907C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_InventoryWorkInProcess" xlink:label="loc_us-gaap_InventoryWorkInProcess_BDB7F266E5F7FFFC5C4FCEEC12DC2F0C" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_InventoryGrossAbstract_BF76AF58396CB8B48D88CEEC12DBD6F1" xlink:to="loc_us-gaap_InventoryWorkInProcess_BDB7F266E5F7FFFC5C4FCEEC12DC2F0C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_InventoryFinishedGoods" xlink:label="loc_us-gaap_InventoryFinishedGoods_5282D0122EA72E4192F0CEEC12DC6FC2" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_InventoryGrossAbstract_BF76AF58396CB8B48D88CEEC12DBD6F1" xlink:to="loc_us-gaap_InventoryFinishedGoods_5282D0122EA72E4192F0CEEC12DC6FC2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_InventoryGross" xlink:label="loc_us-gaap_InventoryGross_452E2F3F92864E979E96CEEC12DCC86E" xlink:type="locator" />
    <link:presentationArc order="4" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_InventoryGrossAbstract_BF76AF58396CB8B48D88CEEC12DBD6F1" xlink:to="loc_us-gaap_InventoryGross_452E2F3F92864E979E96CEEC12DCC86E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_InventoryAdjustmentsAbstract" xlink:label="loc_us-gaap_InventoryAdjustmentsAbstract_806D302D2FA002F01823CEEC12DC57B1" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_InventoryDisclosureAbstract_09D7B6E2A83E51A676E3CEEC12DB52D2" xlink:to="loc_us-gaap_InventoryAdjustmentsAbstract_806D302D2FA002F01823CEEC12DC57B1" xlink:type="arc" />
    <link:loc xlink:href="oesx-20180630.xsd#oesx_InventoryRawMaterialsAndSuppliesValuationReserves" xlink:label="loc_oesx_InventoryRawMaterialsAndSuppliesValuationReserves_DD48F7737ED1E65A0461CEEC12DC043A" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_InventoryAdjustmentsAbstract_806D302D2FA002F01823CEEC12DC57B1" xlink:to="loc_oesx_InventoryRawMaterialsAndSuppliesValuationReserves_DD48F7737ED1E65A0461CEEC12DC043A" xlink:type="arc" />
    <link:loc xlink:href="oesx-20180630.xsd#oesx_InventoryWorkInProcessValuationReserves" xlink:label="loc_oesx_InventoryWorkInProcessValuationReserves_A30DA2AB7A6E0E25DA4ECEEC12DCD947" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_InventoryAdjustmentsAbstract_806D302D2FA002F01823CEEC12DC57B1" xlink:to="loc_oesx_InventoryWorkInProcessValuationReserves_A30DA2AB7A6E0E25DA4ECEEC12DCD947" xlink:type="arc" />
    <link:loc xlink:href="oesx-20180630.xsd#oesx_InventoryFinishedGoodsValuationReserves" xlink:label="loc_oesx_InventoryFinishedGoodsValuationReserves_BFA668E8E071D48348B8CEEC12DD1658" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_InventoryAdjustmentsAbstract_806D302D2FA002F01823CEEC12DC57B1" xlink:to="loc_oesx_InventoryFinishedGoodsValuationReserves_BFA668E8E071D48348B8CEEC12DD1658" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_InventoryValuationReserves" xlink:label="loc_us-gaap_InventoryValuationReserves_B8E812D563BF9B1C5F05CEEC12DD6716" xlink:type="locator" />
    <link:presentationArc order="4" preferredLabel="http://www.xbrl.org/2009/role/negatedTotalLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_InventoryAdjustmentsAbstract_806D302D2FA002F01823CEEC12DC57B1" xlink:to="loc_us-gaap_InventoryValuationReserves_B8E812D563BF9B1C5F05CEEC12DD6716" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_InventoryNetAbstract" xlink:label="loc_us-gaap_InventoryNetAbstract_BF08199C62DA88F32DB5CEEC12DD9120" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_InventoryDisclosureAbstract_09D7B6E2A83E51A676E3CEEC12DB52D2" xlink:to="loc_us-gaap_InventoryNetAbstract_BF08199C62DA88F32DB5CEEC12DD9120" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_InventoryRawMaterialsAndSuppliesNetOfReserves" xlink:label="loc_us-gaap_InventoryRawMaterialsAndSuppliesNetOfReserves_D251DAE56B8E233C99F6CEEC12DE62AD" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_InventoryNetAbstract_BF08199C62DA88F32DB5CEEC12DD9120" xlink:to="loc_us-gaap_InventoryRawMaterialsAndSuppliesNetOfReserves_D251DAE56B8E233C99F6CEEC12DE62AD" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_InventoryWorkInProcessNetOfReserves" xlink:label="loc_us-gaap_InventoryWorkInProcessNetOfReserves_5A4E1543D4DD8632888CCEEC12DE7D1C" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_InventoryNetAbstract_BF08199C62DA88F32DB5CEEC12DD9120" xlink:to="loc_us-gaap_InventoryWorkInProcessNetOfReserves_5A4E1543D4DD8632888CCEEC12DE7D1C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_InventoryFinishedGoodsNetOfReserves" xlink:label="loc_us-gaap_InventoryFinishedGoodsNetOfReserves_60989AB8B06116BBEFD2CEEC12DED00D" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_InventoryNetAbstract_BF08199C62DA88F32DB5CEEC12DD9120" xlink:to="loc_us-gaap_InventoryFinishedGoodsNetOfReserves_60989AB8B06116BBEFD2CEEC12DED00D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_InventoryNet" xlink:label="loc_us-gaap_InventoryNet_54A255635DC8695CB307CEEC12DE6BEC" xlink:type="locator" />
    <link:presentationArc order="4" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_InventoryNetAbstract_BF08199C62DA88F32DB5CEEC12DD9120" xlink:to="loc_us-gaap_InventoryNet_54A255635DC8695CB307CEEC12DE6BEC" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.oesx.com/role/InventoriesNetTables" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_InventoryDisclosureAbstract" xlink:label="loc_us-gaap_InventoryDisclosureAbstract_8522FDEF0043501A3C4ACEEC12E3A3B8" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfInventoryCurrentTableTextBlock" xlink:label="loc_us-gaap_ScheduleOfInventoryCurrentTableTextBlock_70D9D5A9B85D09C19054CEEC12E3BC7A" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_InventoryDisclosureAbstract_8522FDEF0043501A3C4ACEEC12E3A3B8" xlink:to="loc_us-gaap_ScheduleOfInventoryCurrentTableTextBlock_70D9D5A9B85D09C19054CEEC12E3BC7A" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.oesx.com/role/LongTermDebt" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtDisclosureAbstract" xlink:label="loc_us-gaap_DebtDisclosureAbstract_90908B75412650A74278CEEC1216B1A6" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LongTermDebtTextBlock" xlink:label="loc_us-gaap_LongTermDebtTextBlock_49262B8DFDD000AB3B9ACEEC1216120A" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DebtDisclosureAbstract_90908B75412650A74278CEEC1216B1A6" xlink:to="loc_us-gaap_LongTermDebtTextBlock_49262B8DFDD000AB3B9ACEEC1216120A" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.oesx.com/role/LongTermDebtNarrativeDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtDisclosureAbstract" xlink:label="loc_us-gaap_DebtDisclosureAbstract_5EF6F3FA95F38107A11780F9FD9124CA" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LineOfCreditFacilityTable" xlink:label="loc_us-gaap_LineOfCreditFacilityTable_D466212752CA5E2FC04A80F9FD91EA51" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DebtDisclosureAbstract_5EF6F3FA95F38107A11780F9FD9124CA" xlink:to="loc_us-gaap_LineOfCreditFacilityTable_D466212752CA5E2FC04A80F9FD91EA51" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentAxis" xlink:label="loc_us-gaap_DebtInstrumentAxis_69D91BD86F05B253794B80F9FD923644" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_D466212752CA5E2FC04A80F9FD91EA51" xlink:to="loc_us-gaap_DebtInstrumentAxis_69D91BD86F05B253794B80F9FD923644" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_EF409A0939081222A18B80F9FD92F9AD" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DebtInstrumentAxis_69D91BD86F05B253794B80F9FD923644" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_EF409A0939081222A18B80F9FD92F9AD" xlink:type="arc" />
    <link:loc xlink:href="oesx-20180630.xsd#oesx_CreditAgreementMember" xlink:label="loc_oesx_CreditAgreementMember_C31E8B3C1D2B4734B2C480F9FD925732" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_EF409A0939081222A18B80F9FD92F9AD" xlink:to="loc_oesx_CreditAgreementMember_C31E8B3C1D2B4734B2C480F9FD925732" xlink:type="arc" />
    <link:loc xlink:href="oesx-20180630.xsd#oesx_December2014OTAFinanceProgramMember" xlink:label="loc_oesx_December2014OTAFinanceProgramMember_97E91EF39E056A2D105380F9FD931031" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_EF409A0939081222A18B80F9FD92F9AD" xlink:to="loc_oesx_December2014OTAFinanceProgramMember_97E91EF39E056A2D105380F9FD931031" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CreditFacilityAxis" xlink:label="loc_us-gaap_CreditFacilityAxis_F499BF2E85CFFE3C19AB80F9FD931FFB" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_D466212752CA5E2FC04A80F9FD91EA51" xlink:to="loc_us-gaap_CreditFacilityAxis_F499BF2E85CFFE3C19AB80F9FD931FFB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CreditFacilityDomain" xlink:label="loc_us-gaap_CreditFacilityDomain_C6A981E59512A547EAAC80F9FD938470" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_CreditFacilityAxis_F499BF2E85CFFE3C19AB80F9FD931FFB" xlink:to="loc_us-gaap_CreditFacilityDomain_C6A981E59512A547EAAC80F9FD938470" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RevolvingCreditFacilityMember" xlink:label="loc_us-gaap_RevolvingCreditFacilityMember_7B89B4BAEB99877CF75D80F9FD9358B5" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_CreditFacilityDomain_C6A981E59512A547EAAC80F9FD938470" xlink:to="loc_us-gaap_RevolvingCreditFacilityMember_7B89B4BAEB99877CF75D80F9FD9358B5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LetterOfCreditMember" xlink:label="loc_us-gaap_LetterOfCreditMember_784B2923FA17D5EF2C9C80F9FD948406" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_CreditFacilityDomain_C6A981E59512A547EAAC80F9FD938470" xlink:to="loc_us-gaap_LetterOfCreditMember_784B2923FA17D5EF2C9C80F9FD948406" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LineOfCreditFacilityAxis" xlink:label="loc_us-gaap_LineOfCreditFacilityAxis_3EF71E4572A05570E96A80F9FD946FBD" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_D466212752CA5E2FC04A80F9FD91EA51" xlink:to="loc_us-gaap_LineOfCreditFacilityAxis_3EF71E4572A05570E96A80F9FD946FBD" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LineOfCreditFacilityLenderDomain" xlink:label="loc_us-gaap_LineOfCreditFacilityLenderDomain_020EACECCA32ADEAA61180F9FD948BE8" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LineOfCreditFacilityAxis_3EF71E4572A05570E96A80F9FD946FBD" xlink:to="loc_us-gaap_LineOfCreditFacilityLenderDomain_020EACECCA32ADEAA61180F9FD948BE8" xlink:type="arc" />
    <link:loc xlink:href="oesx-20180630.xsd#oesx_WellsFargoBankNationalAssociationMember" xlink:label="loc_oesx_WellsFargoBankNationalAssociationMember_CBD1F00D809A4E35F05B80F9FD948F46" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LineOfCreditFacilityLenderDomain_020EACECCA32ADEAA61180F9FD948BE8" xlink:to="loc_oesx_WellsFargoBankNationalAssociationMember_CBD1F00D809A4E35F05B80F9FD948F46" xlink:type="arc" />
    <link:loc xlink:href="oesx-20180630.xsd#oesx_DeLageLandenFinancialServicesInc.Member" xlink:label="loc_oesx_DeLageLandenFinancialServicesInc.Member_7BA7A35A8B09A60BBC0A80F9FD9A5791" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LineOfCreditFacilityLenderDomain_020EACECCA32ADEAA61180F9FD948BE8" xlink:to="loc_oesx_DeLageLandenFinancialServicesInc.Member_7BA7A35A8B09A60BBC0A80F9FD9A5791" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_VariableRateAxis" xlink:label="loc_us-gaap_VariableRateAxis_7F80A9DA140B1136BD6B80F9FD9A99D6" xlink:type="locator" />
    <link:presentationArc order="4" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_D466212752CA5E2FC04A80F9FD91EA51" xlink:to="loc_us-gaap_VariableRateAxis_7F80A9DA140B1136BD6B80F9FD9A99D6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_VariableRateDomain" xlink:label="loc_us-gaap_VariableRateDomain_8696AC770D65BD5B7D9780F9FD9A17ED" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_VariableRateAxis_7F80A9DA140B1136BD6B80F9FD9A99D6" xlink:to="loc_us-gaap_VariableRateDomain_8696AC770D65BD5B7D9780F9FD9A17ED" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LondonInterbankOfferedRateLIBORMember" xlink:label="loc_us-gaap_LondonInterbankOfferedRateLIBORMember_DA244F8F9048E34A5AE680F9FD9B4679" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_VariableRateDomain_8696AC770D65BD5B7D9780F9FD9A17ED" xlink:to="loc_us-gaap_LondonInterbankOfferedRateLIBORMember_DA244F8F9048E34A5AE680F9FD9B4679" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LongtermDebtTypeAxis" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_588FA73F662A16BB054C80F9FD9B32FD" xlink:type="locator" />
    <link:presentationArc order="5" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_D466212752CA5E2FC04A80F9FD91EA51" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_588FA73F662A16BB054C80F9FD9B32FD" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_B565FD7C38F5EF62712380F9FD9BC20F" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_588FA73F662A16BB054C80F9FD9B32FD" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_B565FD7C38F5EF62712380F9FD9BC20F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SecuredDebtMember" xlink:label="loc_us-gaap_SecuredDebtMember_8576ABA48BAC3D31EE8E80F9FD9B1FD7" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_B565FD7C38F5EF62712380F9FD9BC20F" xlink:to="loc_us-gaap_SecuredDebtMember_8576ABA48BAC3D31EE8E80F9FD9B1FD7" xlink:type="arc" />
    <link:loc xlink:href="oesx-20180630.xsd#oesx_AgreementWithWisconsinDepartmentOfCommerceMember" xlink:label="loc_oesx_AgreementWithWisconsinDepartmentOfCommerceMember_80CB9824F8AE2CF8EA9580F9FD9C793E" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_B565FD7C38F5EF62712380F9FD9BC20F" xlink:to="loc_oesx_AgreementWithWisconsinDepartmentOfCommerceMember_80CB9824F8AE2CF8EA9580F9FD9C793E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ExtinguishmentOfDebtAxis" xlink:label="loc_us-gaap_ExtinguishmentOfDebtAxis_30B1D0735F2ED0F0058080F9FD9CB593" xlink:type="locator" />
    <link:presentationArc order="6" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_D466212752CA5E2FC04A80F9FD91EA51" xlink:to="loc_us-gaap_ExtinguishmentOfDebtAxis_30B1D0735F2ED0F0058080F9FD9CB593" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ExtinguishmentOfDebtTypeDomain" xlink:label="loc_us-gaap_ExtinguishmentOfDebtTypeDomain_96AD36BEC78D534BC75280F9FD9C243E" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ExtinguishmentOfDebtAxis_30B1D0735F2ED0F0058080F9FD9CB593" xlink:to="loc_us-gaap_ExtinguishmentOfDebtTypeDomain_96AD36BEC78D534BC75280F9FD9C243E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CapitalLeaseObligationsMember" xlink:label="loc_us-gaap_CapitalLeaseObligationsMember_B7C6075BCC384868EE6880F9FD9D2FD0" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ExtinguishmentOfDebtTypeDomain_96AD36BEC78D534BC75280F9FD9C243E" xlink:to="loc_us-gaap_CapitalLeaseObligationsMember_B7C6075BCC384868EE6880F9FD9D2FD0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LineOfCreditFacilityLineItems" xlink:label="loc_us-gaap_LineOfCreditFacilityLineItems_A0AB460CEB5F5AEA8E0380F9FD9D57F9" xlink:type="locator" />
    <link:presentationArc order="7" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_D466212752CA5E2FC04A80F9FD91EA51" xlink:to="loc_us-gaap_LineOfCreditFacilityLineItems_A0AB460CEB5F5AEA8E0380F9FD9D57F9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity" xlink:label="loc_us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity_EBE8F58251BBC24866D180F9FD9DFA48" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_A0AB460CEB5F5AEA8E0380F9FD9D57F9" xlink:to="loc_us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity_EBE8F58251BBC24866D180F9FD9DFA48" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LettersOfCreditOutstandingAmount" xlink:label="loc_us-gaap_LettersOfCreditOutstandingAmount_13F8A3409FEC29F6884C80F9FD9D6673" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_A0AB460CEB5F5AEA8E0380F9FD9D57F9" xlink:to="loc_us-gaap_LettersOfCreditOutstandingAmount_13F8A3409FEC29F6884C80F9FD9D6673" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LongTermLineOfCredit" xlink:label="loc_us-gaap_LongTermLineOfCredit_5E58FA14F54D1418385780F9FD9E65B4" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_A0AB460CEB5F5AEA8E0380F9FD9D57F9" xlink:to="loc_us-gaap_LongTermLineOfCredit_5E58FA14F54D1418385780F9FD9E65B4" xlink:type="arc" />
    <link:loc xlink:href="oesx-20180630.xsd#oesx_LineOfCreditFacilityAdditionalBorrowingCapacity" xlink:label="loc_oesx_LineOfCreditFacilityAdditionalBorrowingCapacity_751A9941E92B3B38C1C180F9FD9E3A7B" xlink:type="locator" />
    <link:presentationArc order="4" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_A0AB460CEB5F5AEA8E0380F9FD9D57F9" xlink:to="loc_oesx_LineOfCreditFacilityAdditionalBorrowingCapacity_751A9941E92B3B38C1C180F9FD9E3A7B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity" xlink:label="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_E6A500621367BA58D54280F9FD9E58E2" xlink:type="locator" />
    <link:presentationArc order="5" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_A0AB460CEB5F5AEA8E0380F9FD9D57F9" xlink:to="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_E6A500621367BA58D54280F9FD9E58E2" xlink:type="arc" />
    <link:loc xlink:href="oesx-20180630.xsd#oesx_LineOfCreditFacilityPotentialMaximumBorrowingCapacity" xlink:label="loc_oesx_LineOfCreditFacilityPotentialMaximumBorrowingCapacity_5C6C7BD4783831CF89BB80F9FD9EE5B6" xlink:type="locator" />
    <link:presentationArc order="6" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_A0AB460CEB5F5AEA8E0380F9FD9D57F9" xlink:to="loc_oesx_LineOfCreditFacilityPotentialMaximumBorrowingCapacity_5C6C7BD4783831CF89BB80F9FD9EE5B6" xlink:type="arc" />
    <link:loc xlink:href="oesx-20180630.xsd#oesx_LineOfCreditFacilityCovenantTermsMinimumIndebtednessRatio" xlink:label="loc_oesx_LineOfCreditFacilityCovenantTermsMinimumIndebtednessRatio_10709B3E936591573E2880F9FD9E6AA2" xlink:type="locator" />
    <link:presentationArc order="7" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_A0AB460CEB5F5AEA8E0380F9FD9D57F9" xlink:to="loc_oesx_LineOfCreditFacilityCovenantTermsMinimumIndebtednessRatio_10709B3E936591573E2880F9FD9E6AA2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentBasisSpreadOnVariableRate1" xlink:label="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_54621927026876A585DB80F9FD9E38A9" xlink:type="locator" />
    <link:presentationArc order="8" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_A0AB460CEB5F5AEA8E0380F9FD9D57F9" xlink:to="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_54621927026876A585DB80F9FD9E38A9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentPeriodicPaymentInterest" xlink:label="loc_us-gaap_DebtInstrumentPeriodicPaymentInterest_86E0803F7E31B170543480F9FD9EBBEE" xlink:type="locator" />
    <link:presentationArc order="9" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_A0AB460CEB5F5AEA8E0380F9FD9D57F9" xlink:to="loc_us-gaap_DebtInstrumentPeriodicPaymentInterest_86E0803F7E31B170543480F9FD9EBBEE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentInterestRateEffectivePercentage" xlink:label="loc_us-gaap_DebtInstrumentInterestRateEffectivePercentage_D4D35F6974C0C46BC6F380F9FD9FC82D" xlink:type="locator" />
    <link:presentationArc order="10" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_A0AB460CEB5F5AEA8E0380F9FD9D57F9" xlink:to="loc_us-gaap_DebtInstrumentInterestRateEffectivePercentage_D4D35F6974C0C46BC6F380F9FD9FC82D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LineOfCreditFacilityUnusedCapacityCommitmentFeePercentage" xlink:label="loc_us-gaap_LineOfCreditFacilityUnusedCapacityCommitmentFeePercentage_B583547F77A4F5B21F8E80F9FD9FD5D2" xlink:type="locator" />
    <link:presentationArc order="11" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_A0AB460CEB5F5AEA8E0380F9FD9D57F9" xlink:to="loc_us-gaap_LineOfCreditFacilityUnusedCapacityCommitmentFeePercentage_B583547F77A4F5B21F8E80F9FD9FD5D2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentFaceAmount" xlink:label="loc_us-gaap_DebtInstrumentFaceAmount_44395F416F4E63296BA880F9FD9F85C7" xlink:type="locator" />
    <link:presentationArc order="12" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_A0AB460CEB5F5AEA8E0380F9FD9D57F9" xlink:to="loc_us-gaap_DebtInstrumentFaceAmount_44395F416F4E63296BA880F9FD9F85C7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage" xlink:label="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_D5AB158EBE00DBDFD33C80F9FD9FA681" xlink:type="locator" />
    <link:presentationArc order="13" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_A0AB460CEB5F5AEA8E0380F9FD9D57F9" xlink:to="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_D5AB158EBE00DBDFD33C80F9FD9FA681" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentCarryingAmount" xlink:label="loc_us-gaap_DebtInstrumentCarryingAmount_906401ED75CC7BEECC6880F9FD9FA6A0" xlink:type="locator" />
    <link:presentationArc order="14" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_A0AB460CEB5F5AEA8E0380F9FD9D57F9" xlink:to="loc_us-gaap_DebtInstrumentCarryingAmount_906401ED75CC7BEECC6880F9FD9FA6A0" xlink:type="arc" />
    <link:loc xlink:href="oesx-20180630.xsd#oesx_DebtInstrumentBuyoutOption" xlink:label="loc_oesx_DebtInstrumentBuyoutOption_89A350776BED4BCCA86D80F9FD9F3459" xlink:type="locator" />
    <link:presentationArc order="15" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_A0AB460CEB5F5AEA8E0380F9FD9D57F9" xlink:to="loc_oesx_DebtInstrumentBuyoutOption_89A350776BED4BCCA86D80F9FD9F3459" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SecuredDebt" xlink:label="loc_us-gaap_SecuredDebt_8268A7617B1BA7CF148D80F9FDA066B7" xlink:type="locator" />
    <link:presentationArc order="16" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_A0AB460CEB5F5AEA8E0380F9FD9D57F9" xlink:to="loc_us-gaap_SecuredDebt_8268A7617B1BA7CF148D80F9FDA066B7" xlink:type="arc" />
    <link:loc xlink:href="oesx-20180630.xsd#oesx_DebtInstrumentNumberOfContractsForCollateral" xlink:label="loc_oesx_DebtInstrumentNumberOfContractsForCollateral_51B70776E0398AE366C580F9FDA0FAF8" xlink:type="locator" />
    <link:presentationArc order="17" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_A0AB460CEB5F5AEA8E0380F9FD9D57F9" xlink:to="loc_oesx_DebtInstrumentNumberOfContractsForCollateral_51B70776E0398AE366C580F9FDA0FAF8" xlink:type="arc" />
    <link:loc xlink:href="oesx-20180630.xsd#oesx_PeriodOfTimeWithoutInterestAccruingOrPrincipalPaymentsDue" xlink:label="loc_oesx_PeriodOfTimeWithoutInterestAccruingOrPrincipalPaymentsDue_B315B4BBFF9E336C4C6E80F9FDA028BE" xlink:type="locator" />
    <link:presentationArc order="18" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_A0AB460CEB5F5AEA8E0380F9FD9D57F9" xlink:to="loc_oesx_PeriodOfTimeWithoutInterestAccruingOrPrincipalPaymentsDue_B315B4BBFF9E336C4C6E80F9FDA028BE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentPeriodicPayment" xlink:label="loc_us-gaap_DebtInstrumentPeriodicPayment_E67FF7028792B0EFB05A80F9FDA039A5" xlink:type="locator" />
    <link:presentationArc order="19" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_A0AB460CEB5F5AEA8E0380F9FD9D57F9" xlink:to="loc_us-gaap_DebtInstrumentPeriodicPayment_E67FF7028792B0EFB05A80F9FDA039A5" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.oesx.com/role/LongTermDebtSummaryOfLongTermDebtDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtDisclosureAbstract" xlink:label="loc_us-gaap_DebtDisclosureAbstract_2BDABF65A8EF1D8BF085CEEC120C612F" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfExtinguishmentOfDebtTable" xlink:label="loc_us-gaap_ScheduleOfExtinguishmentOfDebtTable_E0947E58AC83AAC11B3FCEEC120CE4D4" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DebtDisclosureAbstract_2BDABF65A8EF1D8BF085CEEC120C612F" xlink:to="loc_us-gaap_ScheduleOfExtinguishmentOfDebtTable_E0947E58AC83AAC11B3FCEEC120CE4D4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LongtermDebtTypeAxis" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_315EB76AC29E3AF19624CEEC120D61AE" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfExtinguishmentOfDebtTable_E0947E58AC83AAC11B3FCEEC120CE4D4" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_315EB76AC29E3AF19624CEEC120D61AE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_D0F2DA5323AF1531341CCEEC120D22F7" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_315EB76AC29E3AF19624CEEC120D61AE" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_D0F2DA5323AF1531341CCEEC120D22F7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RevolvingCreditFacilityMember" xlink:label="loc_us-gaap_RevolvingCreditFacilityMember_0F134F778C006611A2EECEEC120D30AD" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_D0F2DA5323AF1531341CCEEC120D22F7" xlink:to="loc_us-gaap_RevolvingCreditFacilityMember_0F134F778C006611A2EECEEC120D30AD" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CapitalLeaseObligationsMember" xlink:label="loc_us-gaap_CapitalLeaseObligationsMember_523C241A0D3F8050D61BCEEC120EAA72" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_D0F2DA5323AF1531341CCEEC120D22F7" xlink:to="loc_us-gaap_CapitalLeaseObligationsMember_523C241A0D3F8050D61BCEEC120EAA72" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ExtinguishmentOfDebtLineItems" xlink:label="loc_us-gaap_ExtinguishmentOfDebtLineItems_EF67DC2095B860D4C6F1CEEC120F436F" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfExtinguishmentOfDebtTable_E0947E58AC83AAC11B3FCEEC120CE4D4" xlink:to="loc_us-gaap_ExtinguishmentOfDebtLineItems_EF67DC2095B860D4C6F1CEEC120F436F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LongTermDebtByCurrentAndNoncurrentAbstract" xlink:label="loc_us-gaap_LongTermDebtByCurrentAndNoncurrentAbstract_F70D62E7B9DA2751C374CEEC120F0355" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ExtinguishmentOfDebtLineItems_EF67DC2095B860D4C6F1CEEC120F436F" xlink:to="loc_us-gaap_LongTermDebtByCurrentAndNoncurrentAbstract_F70D62E7B9DA2751C374CEEC120F0355" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LongTermDebt" xlink:label="loc_us-gaap_LongTermDebt_5888747017097FE23178CEEC120FA7C0" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LongTermDebtByCurrentAndNoncurrentAbstract_F70D62E7B9DA2751C374CEEC120F0355" xlink:to="loc_us-gaap_LongTermDebt_5888747017097FE23178CEEC120FA7C0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LongTermDebtCurrent" xlink:label="loc_us-gaap_LongTermDebtCurrent_E9AB33AD24FE3FB1D960CEEC120F7C7D" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LongTermDebtByCurrentAndNoncurrentAbstract_F70D62E7B9DA2751C374CEEC120F0355" xlink:to="loc_us-gaap_LongTermDebtCurrent_E9AB33AD24FE3FB1D960CEEC120F7C7D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LongTermDebtNoncurrent" xlink:label="loc_us-gaap_LongTermDebtNoncurrent_FCC7D14F584058E845F8CEEC1210779B" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LongTermDebtByCurrentAndNoncurrentAbstract_F70D62E7B9DA2751C374CEEC120F0355" xlink:to="loc_us-gaap_LongTermDebtNoncurrent_FCC7D14F584058E845F8CEEC1210779B" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.oesx.com/role/LongTermDebtTables" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtDisclosureAbstract" xlink:label="loc_us-gaap_DebtDisclosureAbstract_B24E4C8F1C9D54C983E13DB4F79D0BD1" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfDebtTableTextBlock" xlink:label="loc_us-gaap_ScheduleOfDebtTableTextBlock_B3AE2D07951B50F38D61CC86A1135954" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DebtDisclosureAbstract_B24E4C8F1C9D54C983E13DB4F79D0BD1" xlink:to="loc_us-gaap_ScheduleOfDebtTableTextBlock_B3AE2D07951B50F38D61CC86A1135954" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.oesx.com/role/NetLossPerCommonShare" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EarningsPerShareAbstract" xlink:label="loc_us-gaap_EarningsPerShareAbstract_4550720C3BDB2D0ADD2CCEEC122E577D" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EarningsPerShareTextBlock" xlink:label="loc_us-gaap_EarningsPerShareTextBlock_6C20275FBDCAB27E2B83CEEC122EF1A3" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_EarningsPerShareAbstract_4550720C3BDB2D0ADD2CCEEC122E577D" xlink:to="loc_us-gaap_EarningsPerShareTextBlock_6C20275FBDCAB27E2B83CEEC122EF1A3" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.oesx.com/role/NetLossPerCommonShareEarningsPerShareDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EarningsPerShareAbstract" xlink:label="loc_us-gaap_EarningsPerShareAbstract_46ABC69CED8A5CD5B328B3BACF00DCF7" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EarningsPerShareReconciliationAbstract" xlink:label="loc_us-gaap_EarningsPerShareReconciliationAbstract_6505D9DFFA1B52ECBFBF2B79C8349B6A" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_EarningsPerShareAbstract_46ABC69CED8A5CD5B328B3BACF00DCF7" xlink:to="loc_us-gaap_EarningsPerShareReconciliationAbstract_6505D9DFFA1B52ECBFBF2B79C8349B6A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="loc_us-gaap_NetIncomeLoss_A4F2B24DF8AF5F80A1D8D50771122612" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_EarningsPerShareReconciliationAbstract_6505D9DFFA1B52ECBFBF2B79C8349B6A" xlink:to="loc_us-gaap_NetIncomeLoss_A4F2B24DF8AF5F80A1D8D50771122612" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_WeightedAverageNumberDilutedSharesOutstandingAdjustmentAbstract" xlink:label="loc_us-gaap_WeightedAverageNumberDilutedSharesOutstandingAdjustmentAbstract_055C11F97499521188513A2D3AC8BF0F" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_EarningsPerShareAbstract_46ABC69CED8A5CD5B328B3BACF00DCF7" xlink:to="loc_us-gaap_WeightedAverageNumberDilutedSharesOutstandingAdjustmentAbstract_055C11F97499521188513A2D3AC8BF0F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_WeightedAverageNumberOfSharesOutstandingBasic" xlink:label="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_117FD1784CA8501E8BB90A6475893F08" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_WeightedAverageNumberDilutedSharesOutstandingAdjustmentAbstract_055C11F97499521188513A2D3AC8BF0F" xlink:to="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_117FD1784CA8501E8BB90A6475893F08" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding" xlink:label="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_5FDD661ED4EF51E994B433DDB10ED1C6" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_WeightedAverageNumberDilutedSharesOutstandingAdjustmentAbstract_055C11F97499521188513A2D3AC8BF0F" xlink:to="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_5FDD661ED4EF51E994B433DDB10ED1C6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EarningsPerShareBasicAndDilutedAbstract" xlink:label="loc_us-gaap_EarningsPerShareBasicAndDilutedAbstract_223E188513855F65A4A6B8D47EF6574D" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_EarningsPerShareAbstract_46ABC69CED8A5CD5B328B3BACF00DCF7" xlink:to="loc_us-gaap_EarningsPerShareBasicAndDilutedAbstract_223E188513855F65A4A6B8D47EF6574D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EarningsPerShareBasic" xlink:label="loc_us-gaap_EarningsPerShareBasic_59940B80BA5F561EBA8C62505FBA001D" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2009/role/netLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_EarningsPerShareBasicAndDilutedAbstract_223E188513855F65A4A6B8D47EF6574D" xlink:to="loc_us-gaap_EarningsPerShareBasic_59940B80BA5F561EBA8C62505FBA001D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EarningsPerShareDiluted" xlink:label="loc_us-gaap_EarningsPerShareDiluted_31A776DC58A85EBD9A33069023008B60" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2009/role/netLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_EarningsPerShareBasicAndDilutedAbstract_223E188513855F65A4A6B8D47EF6574D" xlink:to="loc_us-gaap_EarningsPerShareDiluted_31A776DC58A85EBD9A33069023008B60" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.oesx.com/role/NetLossPerCommonSharePotentiallyDilutiveSecuritiesDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EarningsPerShareAbstract" xlink:label="loc_us-gaap_EarningsPerShareAbstract_CB30D04D0EBE54C3AEC54AE3E2336175" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable" xlink:label="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_E2A3628F424256C0947CDD86270161B3" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_EarningsPerShareAbstract_CB30D04D0EBE54C3AEC54AE3E2336175" xlink:to="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_E2A3628F424256C0947CDD86270161B3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_BE9B730E86825F4580F1649B1E30A6B1" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_E2A3628F424256C0947CDD86270161B3" xlink:to="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_BE9B730E86825F4580F1649B1E30A6B1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AntidilutiveSecuritiesNameDomain" xlink:label="loc_us-gaap_AntidilutiveSecuritiesNameDomain_AA35C4C37316595C9A23D066B5DF50C9" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_BE9B730E86825F4580F1649B1E30A6B1" xlink:to="loc_us-gaap_AntidilutiveSecuritiesNameDomain_AA35C4C37316595C9A23D066B5DF50C9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EmployeeStockOptionMember" xlink:label="loc_us-gaap_EmployeeStockOptionMember_6D9008E4DC215C3DA905E630483E9D06" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AntidilutiveSecuritiesNameDomain_AA35C4C37316595C9A23D066B5DF50C9" xlink:to="loc_us-gaap_EmployeeStockOptionMember_6D9008E4DC215C3DA905E630483E9D06" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RestrictedStockMember" xlink:label="loc_us-gaap_RestrictedStockMember_4C62717A9571526BB06D45C23AA8D4EA" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AntidilutiveSecuritiesNameDomain_AA35C4C37316595C9A23D066B5DF50C9" xlink:to="loc_us-gaap_RestrictedStockMember_4C62717A9571526BB06D45C23AA8D4EA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_A94EC6F848B35BA29D0517035A1902EA" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_E2A3628F424256C0947CDD86270161B3" xlink:to="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_A94EC6F848B35BA29D0517035A1902EA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_08A86BAE32205809B8909786ED374F14" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_A94EC6F848B35BA29D0517035A1902EA" xlink:to="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_08A86BAE32205809B8909786ED374F14" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.oesx.com/role/NetLossPerCommonShareTables" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EarningsPerShareAbstract" xlink:label="loc_us-gaap_EarningsPerShareAbstract_5EE97472005F540F81D63475FE9B0CA8" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfEarningsPerShareBasicAndDilutedTableTextBlock" xlink:label="loc_us-gaap_ScheduleOfEarningsPerShareBasicAndDilutedTableTextBlock_73393D766D485C6D8314EB92C70D0145" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_EarningsPerShareAbstract_5EE97472005F540F81D63475FE9B0CA8" xlink:to="loc_us-gaap_ScheduleOfEarningsPerShareBasicAndDilutedTableTextBlock_73393D766D485C6D8314EB92C70D0145" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTextBlock" xlink:label="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTextBlock_DFFF4A1E5A7552DE9AF56152CC197827" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_EarningsPerShareAbstract_5EE97472005F540F81D63475FE9B0CA8" xlink:to="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTextBlock_DFFF4A1E5A7552DE9AF56152CC197827" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.oesx.com/role/PrepaidExpensesAndOtherCurrentAssets" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DeferredCostsCapitalizedPrepaidAndOtherAssetsDisclosureAbstract" xlink:label="loc_us-gaap_DeferredCostsCapitalizedPrepaidAndOtherAssetsDisclosureAbstract_11FEB5D0BE22E5B98963CEEC12C5AB5E" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherCurrentAssetsTextBlock" xlink:label="loc_us-gaap_OtherCurrentAssetsTextBlock_1EC41139998EBA4C7F6BCEEC12C5952C" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DeferredCostsCapitalizedPrepaidAndOtherAssetsDisclosureAbstract_11FEB5D0BE22E5B98963CEEC12C5AB5E" xlink:to="loc_us-gaap_OtherCurrentAssetsTextBlock_1EC41139998EBA4C7F6BCEEC12C5952C" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.oesx.com/role/PrepaidExpensesAndOtherCurrentAssetsDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DeferredCostsCapitalizedPrepaidAndOtherAssetsDisclosureAbstract" xlink:label="loc_us-gaap_DeferredCostsCapitalizedPrepaidAndOtherAssetsDisclosureAbstract_ADA19C970C05333DB3BF11737796D8E2" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_UnbilledReceivablesCurrent" xlink:label="loc_us-gaap_UnbilledReceivablesCurrent_B0B541F80BCB7F99A6F9117377974A07" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DeferredCostsCapitalizedPrepaidAndOtherAssetsDisclosureAbstract_ADA19C970C05333DB3BF11737796D8E2" xlink:to="loc_us-gaap_UnbilledReceivablesCurrent_B0B541F80BCB7F99A6F9117377974A07" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherPrepaidExpenseCurrent" xlink:label="loc_us-gaap_OtherPrepaidExpenseCurrent_9E514EDF2F2F7D456607117377972D01" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DeferredCostsCapitalizedPrepaidAndOtherAssetsDisclosureAbstract_ADA19C970C05333DB3BF11737796D8E2" xlink:to="loc_us-gaap_OtherPrepaidExpenseCurrent_9E514EDF2F2F7D456607117377972D01" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PrepaidExpenseAndOtherAssetsCurrent" xlink:label="loc_us-gaap_PrepaidExpenseAndOtherAssetsCurrent_824FDA9C6A1C27EA6BB11173779781A0" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DeferredCostsCapitalizedPrepaidAndOtherAssetsDisclosureAbstract_ADA19C970C05333DB3BF11737796D8E2" xlink:to="loc_us-gaap_PrepaidExpenseAndOtherAssetsCurrent_824FDA9C6A1C27EA6BB11173779781A0" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.oesx.com/role/PrepaidExpensesAndOtherCurrentAssetsTables" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DeferredCostsCapitalizedPrepaidAndOtherAssetsDisclosureAbstract" xlink:label="loc_us-gaap_DeferredCostsCapitalizedPrepaidAndOtherAssetsDisclosureAbstract_5DE8336A52F754718FFF9E3DD7E1F8A8" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DeferredCostsCapitalizedPrepaidAndOtherAssetsDisclosureTextBlock" xlink:label="loc_us-gaap_DeferredCostsCapitalizedPrepaidAndOtherAssetsDisclosureTextBlock_95159C0C4D64527BBA833118F6FF69DD" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DeferredCostsCapitalizedPrepaidAndOtherAssetsDisclosureAbstract_5DE8336A52F754718FFF9E3DD7E1F8A8" xlink:to="loc_us-gaap_DeferredCostsCapitalizedPrepaidAndOtherAssetsDisclosureTextBlock_95159C0C4D64527BBA833118F6FF69DD" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.oesx.com/role/PropertyAndEquipmentNet" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PropertyPlantAndEquipmentAbstract" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentAbstract_3BED93593265BCED2F5DCEEC12B5E4E7" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PropertyPlantAndEquipmentDisclosureTextBlock" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentDisclosureTextBlock_D588C7BDB17DE027D95FCEEC12B60C22" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentAbstract_3BED93593265BCED2F5DCEEC12B5E4E7" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentDisclosureTextBlock_D588C7BDB17DE027D95FCEEC12B60C22" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.oesx.com/role/PropertyAndEquipmentNetEquipmentUnderCapitalLeasesDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PropertyPlantAndEquipmentAbstract" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentAbstract_C32BDF7951883DF2DB62CEEC1298AF99" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfCapitalLeasedAsssetsTable" xlink:label="loc_us-gaap_ScheduleOfCapitalLeasedAsssetsTable_AF5DCE58E5200FB380A5CEEC129863A4" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentAbstract_C32BDF7951883DF2DB62CEEC1298AF99" xlink:to="loc_us-gaap_ScheduleOfCapitalLeasedAsssetsTable_AF5DCE58E5200FB380A5CEEC129863A4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PropertyPlantAndEquipmentByTypeAxis" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_BE34C725609FCD757CC1CEEC129872F3" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfCapitalLeasedAsssetsTable_AF5DCE58E5200FB380A5CEEC129863A4" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_BE34C725609FCD757CC1CEEC129872F3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_B83FBF48E869B5C6572FCEEC1299D9D4" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_BE34C725609FCD757CC1CEEC129872F3" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_B83FBF48E869B5C6572FCEEC1299D9D4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AssetsHeldUnderCapitalLeasesMember" xlink:label="loc_us-gaap_AssetsHeldUnderCapitalLeasesMember_8E9A9014366699D634BACEEC1299B267" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_B83FBF48E869B5C6572FCEEC1299D9D4" xlink:to="loc_us-gaap_AssetsHeldUnderCapitalLeasesMember_8E9A9014366699D634BACEEC1299B267" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CapitalLeasedAssetsLineItems" xlink:label="loc_us-gaap_CapitalLeasedAssetsLineItems_6AEBA2FEEF80DCA7636DCEEC1299E0E9" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfCapitalLeasedAsssetsTable_AF5DCE58E5200FB380A5CEEC129863A4" xlink:to="loc_us-gaap_CapitalLeasedAssetsLineItems_6AEBA2FEEF80DCA7636DCEEC1299E0E9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PropertyPlantAndEquipmentGross" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentGross_64729F285587191D419FCEEC1299E082" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_CapitalLeasedAssetsLineItems_6AEBA2FEEF80DCA7636DCEEC1299E0E9" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentGross_64729F285587191D419FCEEC1299E082" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment" xlink:label="loc_us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_318DF6184415847DE75BCEEC129A7CDC" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_CapitalLeasedAssetsLineItems_6AEBA2FEEF80DCA7636DCEEC1299E0E9" xlink:to="loc_us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_318DF6184415847DE75BCEEC129A7CDC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PropertyPlantAndEquipmentNet" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentNet_C64DE7B2C34EA1B3F9B6CEEC129A950B" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_CapitalLeasedAssetsLineItems_6AEBA2FEEF80DCA7636DCEEC1299E0E9" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentNet_C64DE7B2C34EA1B3F9B6CEEC129A950B" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.oesx.com/role/PropertyAndEquipmentNetNarrativeDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PropertyPlantAndEquipmentAbstract" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentAbstract_77861CDAEEC4B42578B0CEEC128E2BF0" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_Depreciation" xlink:label="loc_us-gaap_Depreciation_50A19137E141FD204FBACEEC128E0D3A" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentAbstract_77861CDAEEC4B42578B0CEEC128E2BF0" xlink:to="loc_us-gaap_Depreciation_50A19137E141FD204FBACEEC128E0D3A" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.oesx.com/role/PropertyAndEquipmentNetSummaryOfPropertyAndEquipmentDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PropertyPlantAndEquipmentAbstract" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentAbstract_E2776F1DC58B6F48EB8EFB25821A18C3" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfPropertyPlantAndEquipmentTable" xlink:label="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_ABA740039EEE0B45E7EBFB25821A1BED" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentAbstract_E2776F1DC58B6F48EB8EFB25821A18C3" xlink:to="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_ABA740039EEE0B45E7EBFB25821A1BED" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PropertyPlantAndEquipmentByTypeAxis" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_A1F16626FBBAEF68F235FB25821AB027" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_ABA740039EEE0B45E7EBFB25821A1BED" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_A1F16626FBBAEF68F235FB25821AB027" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_1427C7AF0D93CB67CC17FB25821A6F7F" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_A1F16626FBBAEF68F235FB25821AB027" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_1427C7AF0D93CB67CC17FB25821A6F7F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LandImprovementsMember" xlink:label="loc_us-gaap_LandImprovementsMember_F6036852789839D00EF0FB25821B57B5" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_1427C7AF0D93CB67CC17FB25821A6F7F" xlink:to="loc_us-gaap_LandImprovementsMember_F6036852789839D00EF0FB25821B57B5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BuildingAndBuildingImprovementsMember" xlink:label="loc_us-gaap_BuildingAndBuildingImprovementsMember_2487DD3C07B5769F64AAFB25821B8DBC" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_1427C7AF0D93CB67CC17FB25821A6F7F" xlink:to="loc_us-gaap_BuildingAndBuildingImprovementsMember_2487DD3C07B5769F64AAFB25821B8DBC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FurnitureAndFixturesMember" xlink:label="loc_us-gaap_FurnitureAndFixturesMember_0E8A3E002738D233C251FB25821B9474" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_1427C7AF0D93CB67CC17FB25821A6F7F" xlink:to="loc_us-gaap_FurnitureAndFixturesMember_0E8A3E002738D233C251FB25821B9474" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LeaseholdImprovementsMember" xlink:label="loc_us-gaap_LeaseholdImprovementsMember_ED90B5237680FA284E36FB25821BB2F2" xlink:type="locator" />
    <link:presentationArc order="4" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_1427C7AF0D93CB67CC17FB25821A6F7F" xlink:to="loc_us-gaap_LeaseholdImprovementsMember_ED90B5237680FA284E36FB25821BB2F2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EquipmentLeasedToOtherPartyMember" xlink:label="loc_us-gaap_EquipmentLeasedToOtherPartyMember_5A9048958714C29C2503FB25821BEDF3" xlink:type="locator" />
    <link:presentationArc order="5" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_1427C7AF0D93CB67CC17FB25821A6F7F" xlink:to="loc_us-gaap_EquipmentLeasedToOtherPartyMember_5A9048958714C29C2503FB25821BEDF3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EquipmentMember" xlink:label="loc_us-gaap_EquipmentMember_FC462EAB4314C5B399D2FB25821CDE7E" xlink:type="locator" />
    <link:presentationArc order="6" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_1427C7AF0D93CB67CC17FB25821A6F7F" xlink:to="loc_us-gaap_EquipmentMember_FC462EAB4314C5B399D2FB25821CDE7E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PropertyPlantAndEquipmentLineItems" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentLineItems_4B46C468BF6714420A1DFB25821C8A0E" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_ABA740039EEE0B45E7EBFB25821A1BED" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentLineItems_4B46C468BF6714420A1DFB25821C8A0E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PropertyPlantAndEquipmentNetAbstract" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentNetAbstract_16AB0AC7F3B4BB23D79DFB25821C71F3" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_4B46C468BF6714420A1DFB25821C8A0E" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentNetAbstract_16AB0AC7F3B4BB23D79DFB25821C71F3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PropertyPlantAndEquipmentGross" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentGross_817C48035B57C4F04DE3FB25821C16DF" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentNetAbstract_16AB0AC7F3B4BB23D79DFB25821C71F3" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentGross_817C48035B57C4F04DE3FB25821C16DF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment" xlink:label="loc_us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_72FCF70EE2B9AC63DF6DFB25821D0AB7" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentNetAbstract_16AB0AC7F3B4BB23D79DFB25821C71F3" xlink:to="loc_us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_72FCF70EE2B9AC63DF6DFB25821D0AB7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PropertyPlantAndEquipmentNet" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentNet_BB8A9A2630D2F49A22F9FB25821D7569" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentNetAbstract_16AB0AC7F3B4BB23D79DFB25821C71F3" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentNet_BB8A9A2630D2F49A22F9FB25821D7569" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.oesx.com/role/PropertyAndEquipmentNetTables" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PropertyPlantAndEquipmentAbstract" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentAbstract_F980C38CD8BB631B980ACEEC12AD38C5" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTextBlock" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTextBlock_6A5891C796D98B9205C2CEEC12AD9196" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentAbstract_F980C38CD8BB631B980ACEEC12AD38C5" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTextBlock_6A5891C796D98B9205C2CEEC12AD9196" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfCapitalLeasedAsssetsTableTextBlock" xlink:label="loc_us-gaap_ScheduleOfCapitalLeasedAsssetsTableTextBlock_1D3D7E2FDD09257C3354CEEC12ADCA44" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentAbstract_F980C38CD8BB631B980ACEEC12AD38C5" xlink:to="loc_us-gaap_ScheduleOfCapitalLeasedAsssetsTableTextBlock_1D3D7E2FDD09257C3354CEEC12ADCA44" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.oesx.com/role/RelatedPartyTransactions" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RelatedPartyTransactionsAbstract" xlink:label="loc_us-gaap_RelatedPartyTransactionsAbstract_CA25F0C63B37E15B1BE4CEEC121CCD35" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RelatedPartyTransactionsDisclosureTextBlock" xlink:label="loc_us-gaap_RelatedPartyTransactionsDisclosureTextBlock_A11CD616004278D0D3D4CEEC121C42BB" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_RelatedPartyTransactionsAbstract_CA25F0C63B37E15B1BE4CEEC121CCD35" xlink:to="loc_us-gaap_RelatedPartyTransactionsDisclosureTextBlock_A11CD616004278D0D3D4CEEC121C42BB" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.oesx.com/role/RelatedPartyTransactionsDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RelatedPartyTransactionsAbstract" xlink:label="loc_us-gaap_RelatedPartyTransactionsAbstract_8A1DDADB6D4CD86030F4CEEC12190147" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RelatedPartyTransactionAmountsOfTransaction" xlink:label="loc_us-gaap_RelatedPartyTransactionAmountsOfTransaction_B980108245799373CC3ECEEC12199380" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_RelatedPartyTransactionsAbstract_8A1DDADB6D4CD86030F4CEEC12190147" xlink:to="loc_us-gaap_RelatedPartyTransactionAmountsOfTransaction_B980108245799373CC3ECEEC12199380" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.oesx.com/role/ReorganizationOfBusiness" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RestructuringAndRelatedActivitiesAbstract" xlink:label="loc_us-gaap_RestructuringAndRelatedActivitiesAbstract_2108F3573E81527A5BC4CEEC119E649C" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RestructuringAndRelatedActivitiesDisclosureTextBlock" xlink:label="loc_us-gaap_RestructuringAndRelatedActivitiesDisclosureTextBlock_80398A781F4101E46C67CEEC119E658B" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_RestructuringAndRelatedActivitiesAbstract_2108F3573E81527A5BC4CEEC119E649C" xlink:to="loc_us-gaap_RestructuringAndRelatedActivitiesDisclosureTextBlock_80398A781F4101E46C67CEEC119E658B" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.oesx.com/role/ReorganizationOfBusinessNarrativeDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RestructuringAndRelatedActivitiesAbstract" xlink:label="loc_us-gaap_RestructuringAndRelatedActivitiesAbstract_DC68539770FD2E80E5F4CEEC11827D39" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfRestructuringAndRelatedCostsTable" xlink:label="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_FEA24D4C06EED698B2F8CEEC1182F9EF" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_RestructuringAndRelatedActivitiesAbstract_DC68539770FD2E80E5F4CEEC11827D39" xlink:to="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_FEA24D4C06EED698B2F8CEEC1182F9EF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RestructuringCostAndReserveAxis" xlink:label="loc_us-gaap_RestructuringCostAndReserveAxis_669190EBA0C5217F2349CF529071C7EA" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_FEA24D4C06EED698B2F8CEEC1182F9EF" xlink:to="loc_us-gaap_RestructuringCostAndReserveAxis_669190EBA0C5217F2349CF529071C7EA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_TypeOfRestructuringDomain" xlink:label="loc_us-gaap_TypeOfRestructuringDomain_758215F8A9175708019BCF5290751F07" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_RestructuringCostAndReserveAxis_669190EBA0C5217F2349CF529071C7EA" xlink:to="loc_us-gaap_TypeOfRestructuringDomain_758215F8A9175708019BCF5290751F07" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SpecialTerminationBenefitsMember" xlink:label="loc_us-gaap_SpecialTerminationBenefitsMember_AC754AFE70A67B31E2ACCF5290B2D097" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_TypeOfRestructuringDomain_758215F8A9175708019BCF5290751F07" xlink:to="loc_us-gaap_SpecialTerminationBenefitsMember_AC754AFE70A67B31E2ACCF5290B2D097" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RestructuringCostAndReserveLineItems" xlink:label="loc_us-gaap_RestructuringCostAndReserveLineItems_4E01FA147F0F267EF72BCEEC11841EFE" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_FEA24D4C06EED698B2F8CEEC1182F9EF" xlink:to="loc_us-gaap_RestructuringCostAndReserveLineItems_4E01FA147F0F267EF72BCEEC11841EFE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PaymentsForRestructuring" xlink:label="loc_us-gaap_PaymentsForRestructuring_684092D97A40D9B34504CF528FC0F810" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_RestructuringCostAndReserveLineItems_4E01FA147F0F267EF72BCEEC11841EFE" xlink:to="loc_us-gaap_PaymentsForRestructuring_684092D97A40D9B34504CF528FC0F810" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RestructuringReserve" xlink:label="loc_us-gaap_RestructuringReserve_D24EA3A975333B738CD7CF52904A1B83" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_RestructuringCostAndReserveLineItems_4E01FA147F0F267EF72BCEEC11841EFE" xlink:to="loc_us-gaap_RestructuringReserve_D24EA3A975333B738CD7CF52904A1B83" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.oesx.com/role/ReorganizationOfBusinessRestructuringBySegmentDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RestructuringAndRelatedActivitiesAbstract" xlink:label="loc_us-gaap_RestructuringAndRelatedActivitiesAbstract_7BA8E65CA3051FFF391D145721642AB5" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfRestructuringAndRelatedCostsTable" xlink:label="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_46060D4ECB7D84BBBA8814572164EAFE" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_RestructuringAndRelatedActivitiesAbstract_7BA8E65CA3051FFF391D145721642AB5" xlink:to="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_46060D4ECB7D84BBBA8814572164EAFE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidationItemsAxis" xlink:label="loc_us-gaap_ConsolidationItemsAxis_6975144642008D2F477B14572169576C" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_46060D4ECB7D84BBBA8814572164EAFE" xlink:to="loc_us-gaap_ConsolidationItemsAxis_6975144642008D2F477B14572169576C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidationItemsDomain" xlink:label="loc_us-gaap_ConsolidationItemsDomain_9337A7CDC23D7C644DB41457216ACA1B" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ConsolidationItemsAxis_6975144642008D2F477B14572169576C" xlink:to="loc_us-gaap_ConsolidationItemsDomain_9337A7CDC23D7C644DB41457216ACA1B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OperatingSegmentsMember" xlink:label="loc_us-gaap_OperatingSegmentsMember_AD03BBB21950874EF6BE1457216A515C" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ConsolidationItemsDomain_9337A7CDC23D7C644DB41457216ACA1B" xlink:to="loc_us-gaap_OperatingSegmentsMember_AD03BBB21950874EF6BE1457216A515C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CorporateNonSegmentMember" xlink:label="loc_us-gaap_CorporateNonSegmentMember_45C6DB513C129790B6521457216A735E" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ConsolidationItemsDomain_9337A7CDC23D7C644DB41457216ACA1B" xlink:to="loc_us-gaap_CorporateNonSegmentMember_45C6DB513C129790B6521457216A735E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementBusinessSegmentsAxis" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_838B961CF8861EAADC861457216B408C" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_46060D4ECB7D84BBBA8814572164EAFE" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_838B961CF8861EAADC861457216B408C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SegmentDomain" xlink:label="loc_us-gaap_SegmentDomain_A00E9348CAF2EC08EB891457216B32B0" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_838B961CF8861EAADC861457216B408C" xlink:to="loc_us-gaap_SegmentDomain_A00E9348CAF2EC08EB891457216B32B0" xlink:type="arc" />
    <link:loc xlink:href="oesx-20180630.xsd#oesx_EngineeredSystemsMember" xlink:label="loc_oesx_EngineeredSystemsMember_0FC9987864549A1EE9891457216B3A3B" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_SegmentDomain_A00E9348CAF2EC08EB891457216B32B0" xlink:to="loc_oesx_EngineeredSystemsMember_0FC9987864549A1EE9891457216B3A3B" xlink:type="arc" />
    <link:loc xlink:href="oesx-20180630.xsd#oesx_DistributionServicesMember" xlink:label="loc_oesx_DistributionServicesMember_39BA0319EAA9A00B18511457216B36F3" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_SegmentDomain_A00E9348CAF2EC08EB891457216B32B0" xlink:to="loc_oesx_DistributionServicesMember_39BA0319EAA9A00B18511457216B36F3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RestructuringCostAndReserveLineItems" xlink:label="loc_us-gaap_RestructuringCostAndReserveLineItems_4803EBCD2115C074F2AD1457216B0116" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_46060D4ECB7D84BBBA8814572164EAFE" xlink:to="loc_us-gaap_RestructuringCostAndReserveLineItems_4803EBCD2115C074F2AD1457216B0116" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RestructuringCharges" xlink:label="loc_us-gaap_RestructuringCharges_8D1946F668EE49D719FF1457216C4A40" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_RestructuringCostAndReserveLineItems_4803EBCD2115C074F2AD1457216B0116" xlink:to="loc_us-gaap_RestructuringCharges_8D1946F668EE49D719FF1457216C4A40" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.oesx.com/role/ReorganizationOfBusinessRestructuringByStatementOfOperationsLocationDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RestructuringAndRelatedActivitiesAbstract" xlink:label="loc_us-gaap_RestructuringAndRelatedActivitiesAbstract_7D89508CDBE84719408DCEEC1197A9E6" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfRestructuringAndRelatedCostsTable" xlink:label="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_3799D9B89F5B15FECC61CEEC11984D21" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_RestructuringAndRelatedActivitiesAbstract_7D89508CDBE84719408DCEEC1197A9E6" xlink:to="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_3799D9B89F5B15FECC61CEEC11984D21" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncomeStatementLocationAxis" xlink:label="loc_us-gaap_IncomeStatementLocationAxis_C1110EDD555E199F8736CEEC11980B52" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_3799D9B89F5B15FECC61CEEC11984D21" xlink:to="loc_us-gaap_IncomeStatementLocationAxis_C1110EDD555E199F8736CEEC11980B52" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncomeStatementLocationDomain" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_07034C3502289C949FC9CEEC119836B8" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_C1110EDD555E199F8736CEEC11980B52" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_07034C3502289C949FC9CEEC119836B8" xlink:type="arc" />
    <link:loc xlink:href="oesx-20180630.xsd#oesx_CostOfProductsMember" xlink:label="loc_oesx_CostOfProductsMember_40C66C402B4A1A13EB95CF4FA017E02D" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_07034C3502289C949FC9CEEC119836B8" xlink:to="loc_oesx_CostOfProductsMember_40C66C402B4A1A13EB95CF4FA017E02D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_GeneralAndAdministrativeExpenseMember" xlink:label="loc_us-gaap_GeneralAndAdministrativeExpenseMember_D01A1DC243891CEE2227CEEC1199B3F6" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_07034C3502289C949FC9CEEC119836B8" xlink:to="loc_us-gaap_GeneralAndAdministrativeExpenseMember_D01A1DC243891CEE2227CEEC1199B3F6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SellingAndMarketingExpenseMember" xlink:label="loc_us-gaap_SellingAndMarketingExpenseMember_DB7A053406ADC39EB3D0CEEC11996816" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_07034C3502289C949FC9CEEC119836B8" xlink:to="loc_us-gaap_SellingAndMarketingExpenseMember_DB7A053406ADC39EB3D0CEEC11996816" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RestructuringCostAndReserveLineItems" xlink:label="loc_us-gaap_RestructuringCostAndReserveLineItems_0BF2A85B323A9BB9756ACEEC1199A3BB" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_3799D9B89F5B15FECC61CEEC11984D21" xlink:to="loc_us-gaap_RestructuringCostAndReserveLineItems_0BF2A85B323A9BB9756ACEEC1199A3BB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RestructuringCharges" xlink:label="loc_us-gaap_RestructuringCharges_EEAD94D98638A9FC8F69CEEC11994547" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_RestructuringCostAndReserveLineItems_0BF2A85B323A9BB9756ACEEC1199A3BB" xlink:to="loc_us-gaap_RestructuringCharges_EEAD94D98638A9FC8F69CEEC11994547" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.oesx.com/role/ReorganizationOfBusinessTables" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RestructuringAndRelatedActivitiesAbstract" xlink:label="loc_us-gaap_RestructuringAndRelatedActivitiesAbstract_71DFCACC8A1B8EA92326FB25804D7785" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfRestructuringAndRelatedCostsTextBlock" xlink:label="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTextBlock_DC8DEB83FD0367D58EDCFB25804DE11F" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_RestructuringAndRelatedActivitiesAbstract_71DFCACC8A1B8EA92326FB25804D7785" xlink:to="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTextBlock_DC8DEB83FD0367D58EDCFB25804DE11F" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.oesx.com/role/RevenueDisaggregationOfRevenueDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RevenueFromContractWithCustomerAbstract" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerAbstract_8A7401FD3CFBE7ABB47A117377C92ED4" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DisaggregationOfRevenueTable" xlink:label="loc_us-gaap_DisaggregationOfRevenueTable_ED5C6E23EF6992B293D2117377C91802" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_RevenueFromContractWithCustomerAbstract_8A7401FD3CFBE7ABB47A117377C92ED4" xlink:to="loc_us-gaap_DisaggregationOfRevenueTable_ED5C6E23EF6992B293D2117377C91802" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementBusinessSegmentsAxis" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_32A28D980CD76A872744117377C92A00" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_ED5C6E23EF6992B293D2117377C91802" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_32A28D980CD76A872744117377C92A00" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SegmentDomain" xlink:label="loc_us-gaap_SegmentDomain_4E679A78B59D97BDD438117377C9C697" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_32A28D980CD76A872744117377C92A00" xlink:to="loc_us-gaap_SegmentDomain_4E679A78B59D97BDD438117377C9C697" xlink:type="arc" />
    <link:loc xlink:href="oesx-20180630.xsd#oesx_FederalGovernmentMember" xlink:label="loc_oesx_FederalGovernmentMember_3F62828625E1795975CE11CDB1DAC39B" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_SegmentDomain_4E679A78B59D97BDD438117377C9C697" xlink:to="loc_oesx_FederalGovernmentMember_3F62828625E1795975CE11CDB1DAC39B" xlink:type="arc" />
    <link:loc xlink:href="oesx-20180630.xsd#oesx_CommercialAndIndustrialMember" xlink:label="loc_oesx_CommercialAndIndustrialMember_37CEFC338242FF9F6B3A11D07F6A3F7A" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_SegmentDomain_4E679A78B59D97BDD438117377C9C697" xlink:to="loc_oesx_CommercialAndIndustrialMember_37CEFC338242FF9F6B3A11D07F6A3F7A" xlink:type="arc" />
    <link:loc xlink:href="oesx-20180630.xsd#oesx_LightningMember" xlink:label="loc_oesx_LightningMember_295803A20A6C5A75655D117377CA4A41" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_SegmentDomain_4E679A78B59D97BDD438117377C9C697" xlink:to="loc_oesx_LightningMember_295803A20A6C5A75655D117377CA4A41" xlink:type="arc" />
    <link:loc xlink:href="oesx-20180630.xsd#oesx_SolarEnergyMember" xlink:label="loc_oesx_SolarEnergyMember_5DFD4DE1D1087BFBAC8F117377CA3A1F" xlink:type="locator" />
    <link:presentationArc order="4" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_SegmentDomain_4E679A78B59D97BDD438117377C9C697" xlink:to="loc_oesx_SolarEnergyMember_5DFD4DE1D1087BFBAC8F117377CA3A1F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ProductOrServiceAxis" xlink:label="loc_us-gaap_ProductOrServiceAxis_D07A96D584859047211E117377CAE5EC" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_ED5C6E23EF6992B293D2117377C91802" xlink:to="loc_us-gaap_ProductOrServiceAxis_D07A96D584859047211E117377CAE5EC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ProductsAndServicesDomain" xlink:label="loc_us-gaap_ProductsAndServicesDomain_CC72FD73BCC4F7B8B5C2117377CBE726" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ProductOrServiceAxis_D07A96D584859047211E117377CAE5EC" xlink:to="loc_us-gaap_ProductsAndServicesDomain_CC72FD73BCC4F7B8B5C2117377CBE726" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ProductMember" xlink:label="loc_us-gaap_ProductMember_8F5517B0DFDD99157BDD117377CB27E1" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ProductsAndServicesDomain_CC72FD73BCC4F7B8B5C2117377CBE726" xlink:to="loc_us-gaap_ProductMember_8F5517B0DFDD99157BDD117377CB27E1" xlink:type="arc" />
    <link:loc xlink:href="oesx-20180630.xsd#oesx_ServiceMember" xlink:label="loc_oesx_ServiceMember_11DCDF83C7ED13081536117377CB7F4A" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ProductsAndServicesDomain_CC72FD73BCC4F7B8B5C2117377CBE726" xlink:to="loc_oesx_ServiceMember_11DCDF83C7ED13081536117377CB7F4A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DisaggregationOfRevenueLineItems" xlink:label="loc_us-gaap_DisaggregationOfRevenueLineItems_F519AEB0985D03C9BF3D117377CB5525" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_ED5C6E23EF6992B293D2117377C91802" xlink:to="loc_us-gaap_DisaggregationOfRevenueLineItems_F519AEB0985D03C9BF3D117377CB5525" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RevenueFromContractWithCustomerIncludingAssessedTax" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerIncludingAssessedTax_1A733CBF96D44EBACF1C117377CB3A20" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_F519AEB0985D03C9BF3D117377CB5525" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerIncludingAssessedTax_1A733CBF96D44EBACF1C117377CB3A20" xlink:type="arc" />
    <link:loc xlink:href="oesx-20180630.xsd#oesx_RevenueExcludingRevenueFromContractsWithCustomers" xlink:label="loc_oesx_RevenueExcludingRevenueFromContractsWithCustomers_B6D3423DD71A8BA1402A117377CCBA4D" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_F519AEB0985D03C9BF3D117377CB5525" xlink:to="loc_oesx_RevenueExcludingRevenueFromContractsWithCustomers_B6D3423DD71A8BA1402A117377CCBA4D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_Revenues" xlink:label="loc_us-gaap_Revenues_01AA200EA882E1BCC99A117377CC0A69" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_F519AEB0985D03C9BF3D117377CB5525" xlink:to="loc_us-gaap_Revenues_01AA200EA882E1BCC99A117377CC0A69" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.oesx.com/role/RevenueFinancialStatementImpactOfAdoptingAsc606Details" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RevenueFromContractWithCustomerAbstract" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerAbstract_29A9537FE9E878158DE2117377DCB5FC" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RevenueInitialApplicationPeriodCumulativeEffectTransitionTable" xlink:label="loc_us-gaap_RevenueInitialApplicationPeriodCumulativeEffectTransitionTable_AF7865030CCE7561D316117377DCA70D" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_RevenueFromContractWithCustomerAbstract_29A9537FE9E878158DE2117377DCB5FC" xlink:to="loc_us-gaap_RevenueInitialApplicationPeriodCumulativeEffectTransitionTable_AF7865030CCE7561D316117377DCA70D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ProductOrServiceAxis" xlink:label="loc_us-gaap_ProductOrServiceAxis_C16EC52F517F208B05B5117377DCC01D" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_RevenueInitialApplicationPeriodCumulativeEffectTransitionTable_AF7865030CCE7561D316117377DCA70D" xlink:to="loc_us-gaap_ProductOrServiceAxis_C16EC52F517F208B05B5117377DCC01D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ProductsAndServicesDomain" xlink:label="loc_us-gaap_ProductsAndServicesDomain_66802AA21ABF693DBBE7117377DDE25C" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ProductOrServiceAxis_C16EC52F517F208B05B5117377DCC01D" xlink:to="loc_us-gaap_ProductsAndServicesDomain_66802AA21ABF693DBBE7117377DDE25C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ProductMember" xlink:label="loc_us-gaap_ProductMember_26B5EE141C039D1640FF117377DDB9C9" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ProductsAndServicesDomain_66802AA21ABF693DBBE7117377DDE25C" xlink:to="loc_us-gaap_ProductMember_26B5EE141C039D1640FF117377DDB9C9" xlink:type="arc" />
    <link:loc xlink:href="oesx-20180630.xsd#oesx_ServiceMember" xlink:label="loc_oesx_ServiceMember_FC34EC76A7C92EEE14CC117377DD7B40" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ProductsAndServicesDomain_66802AA21ABF693DBBE7117377DDE25C" xlink:to="loc_oesx_ServiceMember_FC34EC76A7C92EEE14CC117377DD7B40" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_InitialApplicationPeriodCumulativeEffectTransitionAxis" xlink:label="loc_us-gaap_InitialApplicationPeriodCumulativeEffectTransitionAxis_78784F37A43326365ABD117377DDD06F" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_RevenueInitialApplicationPeriodCumulativeEffectTransitionTable_AF7865030CCE7561D316117377DCA70D" xlink:to="loc_us-gaap_InitialApplicationPeriodCumulativeEffectTransitionAxis_78784F37A43326365ABD117377DDD06F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_InitialApplicationPeriodCumulativeEffectTransitionDomain" xlink:label="loc_us-gaap_InitialApplicationPeriodCumulativeEffectTransitionDomain_474FED780EA3F105ED12117377DD63CC" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_InitialApplicationPeriodCumulativeEffectTransitionAxis_78784F37A43326365ABD117377DDD06F" xlink:to="loc_us-gaap_InitialApplicationPeriodCumulativeEffectTransitionDomain_474FED780EA3F105ED12117377DD63CC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DifferenceBetweenRevenueGuidanceInEffectBeforeAndAfterTopic606Member" xlink:label="loc_us-gaap_DifferenceBetweenRevenueGuidanceInEffectBeforeAndAfterTopic606Member_EE2045FDD6A4BE82E6D7117377DE878E" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_InitialApplicationPeriodCumulativeEffectTransitionDomain_474FED780EA3F105ED12117377DD63CC" xlink:to="loc_us-gaap_DifferenceBetweenRevenueGuidanceInEffectBeforeAndAfterTopic606Member_EE2045FDD6A4BE82E6D7117377DE878E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CalculatedUnderRevenueGuidanceInEffectBeforeTopic606Member" xlink:label="loc_us-gaap_CalculatedUnderRevenueGuidanceInEffectBeforeTopic606Member_C47842E644C2DC2D4900117377DF9CCF" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_InitialApplicationPeriodCumulativeEffectTransitionDomain_474FED780EA3F105ED12117377DD63CC" xlink:to="loc_us-gaap_CalculatedUnderRevenueGuidanceInEffectBeforeTopic606Member_C47842E644C2DC2D4900117377DF9CCF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AdjustmentsForNewAccountingPronouncementsAxis" xlink:label="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_CD2E7B8C384E759E1EA2117377DF04FD" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_RevenueInitialApplicationPeriodCumulativeEffectTransitionTable_AF7865030CCE7561D316117377DCA70D" xlink:to="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_CD2E7B8C384E759E1EA2117377DF04FD" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_TypeOfAdoptionMember" xlink:label="loc_us-gaap_TypeOfAdoptionMember_227C316DF1507CF0901B117377DF4111" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_CD2E7B8C384E759E1EA2117377DF04FD" xlink:to="loc_us-gaap_TypeOfAdoptionMember_227C316DF1507CF0901B117377DF4111" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AccountingStandardsUpdate201409Member" xlink:label="loc_us-gaap_AccountingStandardsUpdate201409Member_C48AF0660A434D554A26117377DF007F" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_TypeOfAdoptionMember_227C316DF1507CF0901B117377DF4111" xlink:to="loc_us-gaap_AccountingStandardsUpdate201409Member_C48AF0660A434D554A26117377DF007F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RevenueInitialApplicationPeriodCumulativeEffectTransitionLineItems" xlink:label="loc_us-gaap_RevenueInitialApplicationPeriodCumulativeEffectTransitionLineItems_3E1C5AD8834FA7D8DEED117377DFF0ED" xlink:type="locator" />
    <link:presentationArc order="4" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_RevenueInitialApplicationPeriodCumulativeEffectTransitionTable_AF7865030CCE7561D316117377DCA70D" xlink:to="loc_us-gaap_RevenueInitialApplicationPeriodCumulativeEffectTransitionLineItems_3E1C5AD8834FA7D8DEED117377DFF0ED" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RevenueFromContractWithCustomerIncludingAssessedTax" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerIncludingAssessedTax_3D19B70A64B92DC668D1117377E0E0F0" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_RevenueInitialApplicationPeriodCumulativeEffectTransitionLineItems_3E1C5AD8834FA7D8DEED117377DFF0ED" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerIncludingAssessedTax_3D19B70A64B92DC668D1117377E0E0F0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementOfFinancialPositionAbstract" xlink:label="loc_us-gaap_StatementOfFinancialPositionAbstract_45D6898A89A1DF0BF95C117377E098C3" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_RevenueInitialApplicationPeriodCumulativeEffectTransitionLineItems_3E1C5AD8834FA7D8DEED117377DFF0ED" xlink:to="loc_us-gaap_StatementOfFinancialPositionAbstract_45D6898A89A1DF0BF95C117377E098C3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:label="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_1734207335519AC81121117377E07E43" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfFinancialPositionAbstract_45D6898A89A1DF0BF95C117377E098C3" xlink:to="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_1734207335519AC81121117377E07E43" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AccountsReceivableNetCurrent" xlink:label="loc_us-gaap_AccountsReceivableNetCurrent_65853018947B812FD538117377E0FBD7" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfFinancialPositionAbstract_45D6898A89A1DF0BF95C117377E098C3" xlink:to="loc_us-gaap_AccountsReceivableNetCurrent_65853018947B812FD538117377E0FBD7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_UnbilledContractsReceivable" xlink:label="loc_us-gaap_UnbilledContractsReceivable_F974D4C929E657AB5198117377E09156" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfFinancialPositionAbstract_45D6898A89A1DF0BF95C117377E098C3" xlink:to="loc_us-gaap_UnbilledContractsReceivable_F974D4C929E657AB5198117377E09156" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_InventoryNet" xlink:label="loc_us-gaap_InventoryNet_6F880816D6C18BCD504C117377E09998" xlink:type="locator" />
    <link:presentationArc order="4" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfFinancialPositionAbstract_45D6898A89A1DF0BF95C117377E098C3" xlink:to="loc_us-gaap_InventoryNet_6F880816D6C18BCD504C117377E09998" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DeferredCostsCurrent" xlink:label="loc_us-gaap_DeferredCostsCurrent_8716A56802AE00B8B6F7117377E07D47" xlink:type="locator" />
    <link:presentationArc order="5" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfFinancialPositionAbstract_45D6898A89A1DF0BF95C117377E098C3" xlink:to="loc_us-gaap_DeferredCostsCurrent_8716A56802AE00B8B6F7117377E07D47" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PrepaidExpenseAndOtherAssetsCurrent" xlink:label="loc_us-gaap_PrepaidExpenseAndOtherAssetsCurrent_CE072434459B517481E5117377E031EF" xlink:type="locator" />
    <link:presentationArc order="6" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfFinancialPositionAbstract_45D6898A89A1DF0BF95C117377E098C3" xlink:to="loc_us-gaap_PrepaidExpenseAndOtherAssetsCurrent_CE072434459B517481E5117377E031EF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AssetsCurrent" xlink:label="loc_us-gaap_AssetsCurrent_878D5BE0FDE2BE9935A5117377E14272" xlink:type="locator" />
    <link:presentationArc order="7" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfFinancialPositionAbstract_45D6898A89A1DF0BF95C117377E098C3" xlink:to="loc_us-gaap_AssetsCurrent_878D5BE0FDE2BE9935A5117377E14272" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PropertyPlantAndEquipmentNet" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentNet_3E714C4350210027D6CA117377EDE479" xlink:type="locator" />
    <link:presentationArc order="8" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfFinancialPositionAbstract_45D6898A89A1DF0BF95C117377E098C3" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentNet_3E714C4350210027D6CA117377EDE479" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IntangibleAssetsNetExcludingGoodwill" xlink:label="loc_us-gaap_IntangibleAssetsNetExcludingGoodwill_5305210BFD3C7101EE51117377EE3D1F" xlink:type="locator" />
    <link:presentationArc order="9" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfFinancialPositionAbstract_45D6898A89A1DF0BF95C117377E098C3" xlink:to="loc_us-gaap_IntangibleAssetsNetExcludingGoodwill_5305210BFD3C7101EE51117377EE3D1F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherAssetsNoncurrent" xlink:label="loc_us-gaap_OtherAssetsNoncurrent_E09BDF4DCB1F45A4B509117377EE7FEF" xlink:type="locator" />
    <link:presentationArc order="10" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfFinancialPositionAbstract_45D6898A89A1DF0BF95C117377E098C3" xlink:to="loc_us-gaap_OtherAssetsNoncurrent_E09BDF4DCB1F45A4B509117377EE7FEF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_Assets" xlink:label="loc_us-gaap_Assets_38B8CB0173F9F25FC60B117377EEB75E" xlink:type="locator" />
    <link:presentationArc order="11" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfFinancialPositionAbstract_45D6898A89A1DF0BF95C117377E098C3" xlink:to="loc_us-gaap_Assets_38B8CB0173F9F25FC60B117377EEB75E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AccountsPayableCurrent" xlink:label="loc_us-gaap_AccountsPayableCurrent_98519655D5551D23C674117377EE6562" xlink:type="locator" />
    <link:presentationArc order="12" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfFinancialPositionAbstract_45D6898A89A1DF0BF95C117377E098C3" xlink:to="loc_us-gaap_AccountsPayableCurrent_98519655D5551D23C674117377EE6562" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AccruedLiabilitiesCurrent" xlink:label="loc_us-gaap_AccruedLiabilitiesCurrent_DFBE9D8D6F3ACF75A277117377EEC36C" xlink:type="locator" />
    <link:presentationArc order="13" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfFinancialPositionAbstract_45D6898A89A1DF0BF95C117377E098C3" xlink:to="loc_us-gaap_AccruedLiabilitiesCurrent_DFBE9D8D6F3ACF75A277117377EEC36C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ContractWithCustomerLiabilityCurrent" xlink:label="loc_us-gaap_ContractWithCustomerLiabilityCurrent_BD4632F733A2C508520C117377EF4404" xlink:type="locator" />
    <link:presentationArc order="14" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfFinancialPositionAbstract_45D6898A89A1DF0BF95C117377E098C3" xlink:to="loc_us-gaap_ContractWithCustomerLiabilityCurrent_BD4632F733A2C508520C117377EF4404" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LongTermDebtCurrent" xlink:label="loc_us-gaap_LongTermDebtCurrent_943FCA96710DDCB85006117377EF3E0D" xlink:type="locator" />
    <link:presentationArc order="15" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfFinancialPositionAbstract_45D6898A89A1DF0BF95C117377E098C3" xlink:to="loc_us-gaap_LongTermDebtCurrent_943FCA96710DDCB85006117377EF3E0D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LiabilitiesCurrent" xlink:label="loc_us-gaap_LiabilitiesCurrent_4F826E8EA6261A1C31AD117377EF8F2A" xlink:type="locator" />
    <link:presentationArc order="16" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfFinancialPositionAbstract_45D6898A89A1DF0BF95C117377E098C3" xlink:to="loc_us-gaap_LiabilitiesCurrent_4F826E8EA6261A1C31AD117377EF8F2A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LongTermLineOfCredit" xlink:label="loc_us-gaap_LongTermLineOfCredit_45A8D4D3418B14E96001117377EFCD9D" xlink:type="locator" />
    <link:presentationArc order="17" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfFinancialPositionAbstract_45D6898A89A1DF0BF95C117377E098C3" xlink:to="loc_us-gaap_LongTermLineOfCredit_45A8D4D3418B14E96001117377EFCD9D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherLongTermDebtNoncurrent" xlink:label="loc_us-gaap_OtherLongTermDebtNoncurrent_2FD5A69BB8A2AC40BBC9117377EF8BC8" xlink:type="locator" />
    <link:presentationArc order="18" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfFinancialPositionAbstract_45D6898A89A1DF0BF95C117377E098C3" xlink:to="loc_us-gaap_OtherLongTermDebtNoncurrent_2FD5A69BB8A2AC40BBC9117377EF8BC8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ContractWithCustomerLiabilityNoncurrent" xlink:label="loc_us-gaap_ContractWithCustomerLiabilityNoncurrent_E64A43A5CBA85BC30FFC117377EF7483" xlink:type="locator" />
    <link:presentationArc order="19" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfFinancialPositionAbstract_45D6898A89A1DF0BF95C117377E098C3" xlink:to="loc_us-gaap_ContractWithCustomerLiabilityNoncurrent_E64A43A5CBA85BC30FFC117377EF7483" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherLiabilitiesNoncurrent" xlink:label="loc_us-gaap_OtherLiabilitiesNoncurrent_8F2ADE0ABD7738BCB166117377F00772" xlink:type="locator" />
    <link:presentationArc order="20" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfFinancialPositionAbstract_45D6898A89A1DF0BF95C117377E098C3" xlink:to="loc_us-gaap_OtherLiabilitiesNoncurrent_8F2ADE0ABD7738BCB166117377F00772" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_Liabilities" xlink:label="loc_us-gaap_Liabilities_79FF817CCC573D997DD9117377F024D9" xlink:type="locator" />
    <link:presentationArc order="21" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfFinancialPositionAbstract_45D6898A89A1DF0BF95C117377E098C3" xlink:to="loc_us-gaap_Liabilities_79FF817CCC573D997DD9117377F024D9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CommitmentsAndContingencies" xlink:label="loc_us-gaap_CommitmentsAndContingencies_BFB3F9C3D2F08543CB9B117377F0F782" xlink:type="locator" />
    <link:presentationArc order="22" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfFinancialPositionAbstract_45D6898A89A1DF0BF95C117377E098C3" xlink:to="loc_us-gaap_CommitmentsAndContingencies_BFB3F9C3D2F08543CB9B117377F0F782" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PreferredStockValue" xlink:label="loc_us-gaap_PreferredStockValue_E697DBC533D47F661287117377F0D2D6" xlink:type="locator" />
    <link:presentationArc order="23" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfFinancialPositionAbstract_45D6898A89A1DF0BF95C117377E098C3" xlink:to="loc_us-gaap_PreferredStockValue_E697DBC533D47F661287117377F0D2D6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CommonStockValue" xlink:label="loc_us-gaap_CommonStockValue_B7AB03708DA407BD9E45117377F0399C" xlink:type="locator" />
    <link:presentationArc order="24" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfFinancialPositionAbstract_45D6898A89A1DF0BF95C117377E098C3" xlink:to="loc_us-gaap_CommonStockValue_B7AB03708DA407BD9E45117377F0399C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AdditionalPaidInCapital" xlink:label="loc_us-gaap_AdditionalPaidInCapital_CE966E92C05C1E9A81C0117377F00B7A" xlink:type="locator" />
    <link:presentationArc order="25" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfFinancialPositionAbstract_45D6898A89A1DF0BF95C117377E098C3" xlink:to="loc_us-gaap_AdditionalPaidInCapital_CE966E92C05C1E9A81C0117377F00B7A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_TreasuryStockValue" xlink:label="loc_us-gaap_TreasuryStockValue_6342AB231C1A9C3D04E7117377F1F5DD" xlink:type="locator" />
    <link:presentationArc order="26" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfFinancialPositionAbstract_45D6898A89A1DF0BF95C117377E098C3" xlink:to="loc_us-gaap_TreasuryStockValue_6342AB231C1A9C3D04E7117377F1F5DD" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RetainedEarningsAccumulatedDeficit" xlink:label="loc_us-gaap_RetainedEarningsAccumulatedDeficit_37253EBC5F51526A4E29117377F1CAEB" xlink:type="locator" />
    <link:presentationArc order="27" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfFinancialPositionAbstract_45D6898A89A1DF0BF95C117377E098C3" xlink:to="loc_us-gaap_RetainedEarningsAccumulatedDeficit_37253EBC5F51526A4E29117377F1CAEB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StockholdersEquity" xlink:label="loc_us-gaap_StockholdersEquity_7EF21F9B0435019BBDB1117377F1BA44" xlink:type="locator" />
    <link:presentationArc order="28" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfFinancialPositionAbstract_45D6898A89A1DF0BF95C117377E098C3" xlink:to="loc_us-gaap_StockholdersEquity_7EF21F9B0435019BBDB1117377F1BA44" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LiabilitiesAndStockholdersEquity" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquity_29C768EA3E69C1DB422C117377F1A21D" xlink:type="locator" />
    <link:presentationArc order="29" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfFinancialPositionAbstract_45D6898A89A1DF0BF95C117377E098C3" xlink:to="loc_us-gaap_LiabilitiesAndStockholdersEquity_29C768EA3E69C1DB422C117377F1A21D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncomeStatementAbstract" xlink:label="loc_us-gaap_IncomeStatementAbstract_3CEFA7B8673B98B2DCC4117377F136EC" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_RevenueInitialApplicationPeriodCumulativeEffectTransitionLineItems_3E1C5AD8834FA7D8DEED117377DFF0ED" xlink:to="loc_us-gaap_IncomeStatementAbstract_3CEFA7B8673B98B2DCC4117377F136EC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_Revenues" xlink:label="loc_us-gaap_Revenues_A4C588F493A2BA484614117377F1B098" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncomeStatementAbstract_3CEFA7B8673B98B2DCC4117377F136EC" xlink:to="loc_us-gaap_Revenues_A4C588F493A2BA484614117377F1B098" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CostOfGoodsAndServicesSold" xlink:label="loc_us-gaap_CostOfGoodsAndServicesSold_29CAF9B40A72CD1B5109117377F243D2" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncomeStatementAbstract_3CEFA7B8673B98B2DCC4117377F136EC" xlink:to="loc_us-gaap_CostOfGoodsAndServicesSold_29CAF9B40A72CD1B5109117377F243D2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_GrossProfit" xlink:label="loc_us-gaap_GrossProfit_F50412C3A0CAD5D06730117377F22E09" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncomeStatementAbstract_3CEFA7B8673B98B2DCC4117377F136EC" xlink:to="loc_us-gaap_GrossProfit_F50412C3A0CAD5D06730117377F22E09" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_GeneralAndAdministrativeExpense" xlink:label="loc_us-gaap_GeneralAndAdministrativeExpense_CD876F956DEED9D1F89B117377F21D76" xlink:type="locator" />
    <link:presentationArc order="4" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncomeStatementAbstract_3CEFA7B8673B98B2DCC4117377F136EC" xlink:to="loc_us-gaap_GeneralAndAdministrativeExpense_CD876F956DEED9D1F89B117377F21D76" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SellingAndMarketingExpense" xlink:label="loc_us-gaap_SellingAndMarketingExpense_77CCE150EFE0AE4A9612117377F2FFB5" xlink:type="locator" />
    <link:presentationArc order="5" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncomeStatementAbstract_3CEFA7B8673B98B2DCC4117377F136EC" xlink:to="loc_us-gaap_SellingAndMarketingExpense_77CCE150EFE0AE4A9612117377F2FFB5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ResearchAndDevelopmentExpense" xlink:label="loc_us-gaap_ResearchAndDevelopmentExpense_31AB90E0FBAD3FD77B2F117377F20AE3" xlink:type="locator" />
    <link:presentationArc order="6" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncomeStatementAbstract_3CEFA7B8673B98B2DCC4117377F136EC" xlink:to="loc_us-gaap_ResearchAndDevelopmentExpense_31AB90E0FBAD3FD77B2F117377F20AE3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OperatingExpenses" xlink:label="loc_us-gaap_OperatingExpenses_501A1B3E5BA26E1794DF117377F3C749" xlink:type="locator" />
    <link:presentationArc order="7" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncomeStatementAbstract_3CEFA7B8673B98B2DCC4117377F136EC" xlink:to="loc_us-gaap_OperatingExpenses_501A1B3E5BA26E1794DF117377F3C749" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OperatingIncomeLoss" xlink:label="loc_us-gaap_OperatingIncomeLoss_6B07498D50A20E89E1D3117377F30A0E" xlink:type="locator" />
    <link:presentationArc order="8" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncomeStatementAbstract_3CEFA7B8673B98B2DCC4117377F136EC" xlink:to="loc_us-gaap_OperatingIncomeLoss_6B07498D50A20E89E1D3117377F30A0E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherNonoperatingIncome" xlink:label="loc_us-gaap_OtherNonoperatingIncome_92431E71A627BAD8775F117377F39081" xlink:type="locator" />
    <link:presentationArc order="9" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncomeStatementAbstract_3CEFA7B8673B98B2DCC4117377F136EC" xlink:to="loc_us-gaap_OtherNonoperatingIncome_92431E71A627BAD8775F117377F39081" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_InterestExpense" xlink:label="loc_us-gaap_InterestExpense_7A724FDD7EA25D11CCDA117377F3DE27" xlink:type="locator" />
    <link:presentationArc order="10" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncomeStatementAbstract_3CEFA7B8673B98B2DCC4117377F136EC" xlink:to="loc_us-gaap_InterestExpense_7A724FDD7EA25D11CCDA117377F3DE27" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_InvestmentIncomeInterest" xlink:label="loc_us-gaap_InvestmentIncomeInterest_72D0EFC12685AB96C332117377F377EA" xlink:type="locator" />
    <link:presentationArc order="11" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncomeStatementAbstract_3CEFA7B8673B98B2DCC4117377F136EC" xlink:to="loc_us-gaap_InvestmentIncomeInterest_72D0EFC12685AB96C332117377F377EA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NonoperatingIncomeExpense" xlink:label="loc_us-gaap_NonoperatingIncomeExpense_F27C1260258C26F6AE13117377F32A44" xlink:type="locator" />
    <link:presentationArc order="12" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncomeStatementAbstract_3CEFA7B8673B98B2DCC4117377F136EC" xlink:to="loc_us-gaap_NonoperatingIncomeExpense_F27C1260258C26F6AE13117377F32A44" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments_60AF08019C80A4B9118F117377F31387" xlink:type="locator" />
    <link:presentationArc order="13" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncomeStatementAbstract_3CEFA7B8673B98B2DCC4117377F136EC" xlink:to="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments_60AF08019C80A4B9118F117377F31387" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncomeTaxExpenseBenefit" xlink:label="loc_us-gaap_IncomeTaxExpenseBenefit_A2887266BCEC851579BB117377F43E83" xlink:type="locator" />
    <link:presentationArc order="14" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncomeStatementAbstract_3CEFA7B8673B98B2DCC4117377F136EC" xlink:to="loc_us-gaap_IncomeTaxExpenseBenefit_A2887266BCEC851579BB117377F43E83" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="loc_us-gaap_NetIncomeLoss_86A2BDCD2B154BABC786117377F40589" xlink:type="locator" />
    <link:presentationArc order="15" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncomeStatementAbstract_3CEFA7B8673B98B2DCC4117377F136EC" xlink:to="loc_us-gaap_NetIncomeLoss_86A2BDCD2B154BABC786117377F40589" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EarningsPerShareBasic" xlink:label="loc_us-gaap_EarningsPerShareBasic_E37F06C51D10248431DC117377F4CB75" xlink:type="locator" />
    <link:presentationArc order="16" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncomeStatementAbstract_3CEFA7B8673B98B2DCC4117377F136EC" xlink:to="loc_us-gaap_EarningsPerShareBasic_E37F06C51D10248431DC117377F4CB75" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_WeightedAverageNumberOfSharesOutstandingBasic" xlink:label="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_4DAFB5B647F4DA336F55117377F4FAF0" xlink:type="locator" />
    <link:presentationArc order="17" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncomeStatementAbstract_3CEFA7B8673B98B2DCC4117377F136EC" xlink:to="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_4DAFB5B647F4DA336F55117377F4FAF0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EarningsPerShareDiluted" xlink:label="loc_us-gaap_EarningsPerShareDiluted_0A7AEB2EF226A54BB45C117377F42986" xlink:type="locator" />
    <link:presentationArc order="18" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncomeStatementAbstract_3CEFA7B8673B98B2DCC4117377F136EC" xlink:to="loc_us-gaap_EarningsPerShareDiluted_0A7AEB2EF226A54BB45C117377F42986" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding" xlink:label="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_2F9D986EBF38F848CF22117377F484E2" xlink:type="locator" />
    <link:presentationArc order="19" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncomeStatementAbstract_3CEFA7B8673B98B2DCC4117377F136EC" xlink:to="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_2F9D986EBF38F848CF22117377F484E2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementOfCashFlowsAbstract" xlink:label="loc_us-gaap_StatementOfCashFlowsAbstract_7BEEB0794AD9533E5DC7117377F5A441" xlink:type="locator" />
    <link:presentationArc order="4" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_RevenueInitialApplicationPeriodCumulativeEffectTransitionLineItems_3E1C5AD8834FA7D8DEED117377DFF0ED" xlink:to="loc_us-gaap_StatementOfCashFlowsAbstract_7BEEB0794AD9533E5DC7117377F5A441" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_Depreciation" xlink:label="loc_us-gaap_Depreciation_352BD91DA8D1A1026865117377F50DC4" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfCashFlowsAbstract_7BEEB0794AD9533E5DC7117377F5A441" xlink:to="loc_us-gaap_Depreciation_352BD91DA8D1A1026865117377F50DC4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AdjustmentForAmortization" xlink:label="loc_us-gaap_AdjustmentForAmortization_A7A972075E84D7983D45117377F56C9E" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfCashFlowsAbstract_7BEEB0794AD9533E5DC7117377F5A441" xlink:to="loc_us-gaap_AdjustmentForAmortization_A7A972075E84D7983D45117377F56C9E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareBasedCompensation" xlink:label="loc_us-gaap_ShareBasedCompensation_74036C4CB1020DFCF1C4117377F53259" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfCashFlowsAbstract_7BEEB0794AD9533E5DC7117377F5A441" xlink:to="loc_us-gaap_ShareBasedCompensation_74036C4CB1020DFCF1C4117377F53259" xlink:type="arc" />
    <link:loc xlink:href="oesx-20180630.xsd#oesx_ProvisionForInventoryReserves" xlink:label="loc_oesx_ProvisionForInventoryReserves_449AE9ACC529F0B35804117377F5D96B" xlink:type="locator" />
    <link:presentationArc order="4" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfCashFlowsAbstract_7BEEB0794AD9533E5DC7117377F5A441" xlink:to="loc_oesx_ProvisionForInventoryReserves_449AE9ACC529F0B35804117377F5D96B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ProvisionForDoubtfulAccounts" xlink:label="loc_us-gaap_ProvisionForDoubtfulAccounts_5225FB45472673C62427117377F68BED" xlink:type="locator" />
    <link:presentationArc order="5" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfCashFlowsAbstract_7BEEB0794AD9533E5DC7117377F5A441" xlink:to="loc_us-gaap_ProvisionForDoubtfulAccounts_5225FB45472673C62427117377F68BED" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherNoncashIncomeExpense" xlink:label="loc_us-gaap_OtherNoncashIncomeExpense_0CB2AA7228EBE2CE4865117377FB1639" xlink:type="locator" />
    <link:presentationArc order="6" preferredLabel="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfCashFlowsAbstract_7BEEB0794AD9533E5DC7117377F5A441" xlink:to="loc_us-gaap_OtherNoncashIncomeExpense_0CB2AA7228EBE2CE4865117377FB1639" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncreaseDecreaseInAccountsReceivable" xlink:label="loc_us-gaap_IncreaseDecreaseInAccountsReceivable_98D5756E687C18614C50117377FBF043" xlink:type="locator" />
    <link:presentationArc order="7" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfCashFlowsAbstract_7BEEB0794AD9533E5DC7117377F5A441" xlink:to="loc_us-gaap_IncreaseDecreaseInAccountsReceivable_98D5756E687C18614C50117377FBF043" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncreaseDecreaseInUnbilledReceivables" xlink:label="loc_us-gaap_IncreaseDecreaseInUnbilledReceivables_F2AAA7B23B3297428BEF117377FB7246" xlink:type="locator" />
    <link:presentationArc order="8" preferredLabel="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfCashFlowsAbstract_7BEEB0794AD9533E5DC7117377F5A441" xlink:to="loc_us-gaap_IncreaseDecreaseInUnbilledReceivables_F2AAA7B23B3297428BEF117377FB7246" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncreaseDecreaseInInventories" xlink:label="loc_us-gaap_IncreaseDecreaseInInventories_9D626EF674201D636808117377FC1221" xlink:type="locator" />
    <link:presentationArc order="9" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfCashFlowsAbstract_7BEEB0794AD9533E5DC7117377F5A441" xlink:to="loc_us-gaap_IncreaseDecreaseInInventories_9D626EF674201D636808117377FC1221" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncreaseDecreaseInDeferredCharges" xlink:label="loc_us-gaap_IncreaseDecreaseInDeferredCharges_7E684C3B69117EC7260C117377FC7673" xlink:type="locator" />
    <link:presentationArc order="10" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfCashFlowsAbstract_7BEEB0794AD9533E5DC7117377F5A441" xlink:to="loc_us-gaap_IncreaseDecreaseInDeferredCharges_7E684C3B69117EC7260C117377FC7673" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets" xlink:label="loc_us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets_B1A0265800C7C67F58EF117377FC99A9" xlink:type="locator" />
    <link:presentationArc order="11" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfCashFlowsAbstract_7BEEB0794AD9533E5DC7117377F5A441" xlink:to="loc_us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets_B1A0265800C7C67F58EF117377FC99A9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncreaseDecreaseInAccountsPayable" xlink:label="loc_us-gaap_IncreaseDecreaseInAccountsPayable_333E62A53648025759A9117377FCE077" xlink:type="locator" />
    <link:presentationArc order="12" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfCashFlowsAbstract_7BEEB0794AD9533E5DC7117377F5A441" xlink:to="loc_us-gaap_IncreaseDecreaseInAccountsPayable_333E62A53648025759A9117377FCE077" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncreaseDecreaseInAccruedLiabilities" xlink:label="loc_us-gaap_IncreaseDecreaseInAccruedLiabilities_2F89A5C3CA2101344CD8117377FC4FD5" xlink:type="locator" />
    <link:presentationArc order="13" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfCashFlowsAbstract_7BEEB0794AD9533E5DC7117377F5A441" xlink:to="loc_us-gaap_IncreaseDecreaseInAccruedLiabilities_2F89A5C3CA2101344CD8117377FC4FD5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncreaseDecreaseInDeferredRevenue" xlink:label="loc_us-gaap_IncreaseDecreaseInDeferredRevenue_D5D32B534A38B5F7012A117377FC1234" xlink:type="locator" />
    <link:presentationArc order="14" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfCashFlowsAbstract_7BEEB0794AD9533E5DC7117377F5A441" xlink:to="loc_us-gaap_IncreaseDecreaseInDeferredRevenue_D5D32B534A38B5F7012A117377FC1234" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:label="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_55ECF1D057394A712298117377FD358B" xlink:type="locator" />
    <link:presentationArc order="15" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfCashFlowsAbstract_7BEEB0794AD9533E5DC7117377F5A441" xlink:to="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_55ECF1D057394A712298117377FD358B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PaymentsToAcquirePropertyPlantAndEquipment" xlink:label="loc_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_07C41C396503FFA055C4117377FDB7F0" xlink:type="locator" />
    <link:presentationArc order="16" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfCashFlowsAbstract_7BEEB0794AD9533E5DC7117377F5A441" xlink:to="loc_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_07C41C396503FFA055C4117377FDB7F0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PaymentsToAcquireIntangibleAssets" xlink:label="loc_us-gaap_PaymentsToAcquireIntangibleAssets_4CDC59D019EA5E3C0A30117377FD048C" xlink:type="locator" />
    <link:presentationArc order="17" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfCashFlowsAbstract_7BEEB0794AD9533E5DC7117377F5A441" xlink:to="loc_us-gaap_PaymentsToAcquireIntangibleAssets_4CDC59D019EA5E3C0A30117377FD048C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ProceedsFromSaleOfPropertyPlantAndEquipment" xlink:label="loc_us-gaap_ProceedsFromSaleOfPropertyPlantAndEquipment_170AE0DBBAC95734CC64117377FDEA74" xlink:type="locator" />
    <link:presentationArc order="18" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfCashFlowsAbstract_7BEEB0794AD9533E5DC7117377F5A441" xlink:to="loc_us-gaap_ProceedsFromSaleOfPropertyPlantAndEquipment_170AE0DBBAC95734CC64117377FDEA74" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:label="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_91CC8B155A9B1554E129117377FDDF68" xlink:type="locator" />
    <link:presentationArc order="19" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfCashFlowsAbstract_7BEEB0794AD9533E5DC7117377F5A441" xlink:to="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_91CC8B155A9B1554E129117377FDDF68" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RepaymentsOfLongTermDebt" xlink:label="loc_us-gaap_RepaymentsOfLongTermDebt_28A69CBE0C30E736FBD7117377FDA4B1" xlink:type="locator" />
    <link:presentationArc order="20" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfCashFlowsAbstract_7BEEB0794AD9533E5DC7117377F5A441" xlink:to="loc_us-gaap_RepaymentsOfLongTermDebt_28A69CBE0C30E736FBD7117377FDA4B1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ProceedsFromLongTermLinesOfCredit" xlink:label="loc_us-gaap_ProceedsFromLongTermLinesOfCredit_4676E4C37277EE826531117377FEAF6A" xlink:type="locator" />
    <link:presentationArc order="21" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfCashFlowsAbstract_7BEEB0794AD9533E5DC7117377F5A441" xlink:to="loc_us-gaap_ProceedsFromLongTermLinesOfCredit_4676E4C37277EE826531117377FEAF6A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RepaymentsOfLongTermLinesOfCredit" xlink:label="loc_us-gaap_RepaymentsOfLongTermLinesOfCredit_E7E2D2CB63E410069F24117377FEC716" xlink:type="locator" />
    <link:presentationArc order="22" preferredLabel="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfCashFlowsAbstract_7BEEB0794AD9533E5DC7117377F5A441" xlink:to="loc_us-gaap_RepaymentsOfLongTermLinesOfCredit_E7E2D2CB63E410069F24117377FEC716" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PaymentsRelatedToTaxWithholdingForShareBasedCompensation" xlink:label="loc_us-gaap_PaymentsRelatedToTaxWithholdingForShareBasedCompensation_D9F9CBA0C7E930A39460117377FE668B" xlink:type="locator" />
    <link:presentationArc order="23" preferredLabel="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfCashFlowsAbstract_7BEEB0794AD9533E5DC7117377F5A441" xlink:to="loc_us-gaap_PaymentsRelatedToTaxWithholdingForShareBasedCompensation_D9F9CBA0C7E930A39460117377FE668B" xlink:type="arc" />
    <link:loc xlink:href="oesx-20180630.xsd#oesx_ProceedsFromExerciseOfWarrantsAndStockOptions" xlink:label="loc_oesx_ProceedsFromExerciseOfWarrantsAndStockOptions_66781218EB969B46AA0D117377FEE040" xlink:type="locator" />
    <link:presentationArc order="24" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfCashFlowsAbstract_7BEEB0794AD9533E5DC7117377F5A441" xlink:to="loc_oesx_ProceedsFromExerciseOfWarrantsAndStockOptions_66781218EB969B46AA0D117377FEE040" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:label="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_A7AF2FAE815E823AE2DE117377FE995D" xlink:type="locator" />
    <link:presentationArc order="25" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfCashFlowsAbstract_7BEEB0794AD9533E5DC7117377F5A441" xlink:to="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_A7AF2FAE815E823AE2DE117377FE995D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease" xlink:label="loc_us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease_D6FFCDED55CF462D0724117377FE8145" xlink:type="locator" />
    <link:presentationArc order="26" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfCashFlowsAbstract_7BEEB0794AD9533E5DC7117377F5A441" xlink:to="loc_us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease_D6FFCDED55CF462D0724117377FE8145" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.oesx.com/role/RevenueNarrativeDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RevenueFromContractWithCustomerAbstract" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerAbstract_859EDB1B5ABA1BC6878612F4CDFEE5ED" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DisaggregationOfRevenueTable" xlink:label="loc_us-gaap_DisaggregationOfRevenueTable_B48A9689027025A260AD12F4CDFE451A" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_RevenueFromContractWithCustomerAbstract_859EDB1B5ABA1BC6878612F4CDFEE5ED" xlink:to="loc_us-gaap_DisaggregationOfRevenueTable_B48A9689027025A260AD12F4CDFE451A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ProductOrServiceAxis" xlink:label="loc_us-gaap_ProductOrServiceAxis_44E2BF6D69784ECBDE5512F4CDFE3AB8" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_B48A9689027025A260AD12F4CDFE451A" xlink:to="loc_us-gaap_ProductOrServiceAxis_44E2BF6D69784ECBDE5512F4CDFE3AB8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ProductsAndServicesDomain" xlink:label="loc_us-gaap_ProductsAndServicesDomain_78DEF05F5A291D2BC49512F4CDFFB84F" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ProductOrServiceAxis_44E2BF6D69784ECBDE5512F4CDFE3AB8" xlink:to="loc_us-gaap_ProductsAndServicesDomain_78DEF05F5A291D2BC49512F4CDFFB84F" xlink:type="arc" />
    <link:loc xlink:href="oesx-20180630.xsd#oesx_ProductLightFixtureSalesTypeLeaseMember" xlink:label="loc_oesx_ProductLightFixtureSalesTypeLeaseMember_8E80CD6B1DFD4E1AB94612F4CDFF9BEC" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ProductsAndServicesDomain_78DEF05F5A291D2BC49512F4CDFFB84F" xlink:to="loc_oesx_ProductLightFixtureSalesTypeLeaseMember_8E80CD6B1DFD4E1AB94612F4CDFF9BEC" xlink:type="arc" />
    <link:loc xlink:href="oesx-20180630.xsd#oesx_ProductSaleOfTaxCreditMember" xlink:label="loc_oesx_ProductSaleOfTaxCreditMember_B5351BF0474476A00F8912F4CDFF3897" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ProductsAndServicesDomain_78DEF05F5A291D2BC49512F4CDFFB84F" xlink:to="loc_oesx_ProductSaleOfTaxCreditMember_B5351BF0474476A00F8912F4CDFF3897" xlink:type="arc" />
    <link:loc xlink:href="oesx-20180630.xsd#oesx_ProductLegacySolarFacilitiesMember" xlink:label="loc_oesx_ProductLegacySolarFacilitiesMember_505660F13207EABCCC9112F4CDFFB26C" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ProductsAndServicesDomain_78DEF05F5A291D2BC49512F4CDFFB84F" xlink:to="loc_oesx_ProductLegacySolarFacilitiesMember_505660F13207EABCCC9112F4CDFFB26C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_TimingOfTransferOfGoodOrServiceAxis" xlink:label="loc_us-gaap_TimingOfTransferOfGoodOrServiceAxis_6A591A9E72408484F62C12F4CE0061C7" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_B48A9689027025A260AD12F4CDFE451A" xlink:to="loc_us-gaap_TimingOfTransferOfGoodOrServiceAxis_6A591A9E72408484F62C12F4CE0061C7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_TimingOfTransferOfGoodOrServiceDomain" xlink:label="loc_us-gaap_TimingOfTransferOfGoodOrServiceDomain_E20FE5CDBE28D4D1FD2C12F4CE00FEDB" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_TimingOfTransferOfGoodOrServiceAxis_6A591A9E72408484F62C12F4CE0061C7" xlink:to="loc_us-gaap_TimingOfTransferOfGoodOrServiceDomain_E20FE5CDBE28D4D1FD2C12F4CE00FEDB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_TransferredOverTimeMember" xlink:label="loc_us-gaap_TransferredOverTimeMember_1008A54B097C4827FF5012F4CE00B618" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_TimingOfTransferOfGoodOrServiceDomain_E20FE5CDBE28D4D1FD2C12F4CE00FEDB" xlink:to="loc_us-gaap_TransferredOverTimeMember_1008A54B097C4827FF5012F4CE00B618" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DisaggregationOfRevenueLineItems" xlink:label="loc_us-gaap_DisaggregationOfRevenueLineItems_FF5167E410F67F0825FC12F4CE0074F5" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_B48A9689027025A260AD12F4CDFE451A" xlink:to="loc_us-gaap_DisaggregationOfRevenueLineItems_FF5167E410F67F0825FC12F4CE0074F5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RevenueFromContractWithCustomerIncludingAssessedTax" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerIncludingAssessedTax_7B11D307FFA401D2772112F4CE01728B" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_FF5167E410F67F0825FC12F4CE0074F5" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerIncludingAssessedTax_7B11D307FFA401D2772112F4CE01728B" xlink:type="arc" />
    <link:loc xlink:href="oesx-20180630.xsd#oesx_ProceedsFromSaleofUnbilledContractsReceivable" xlink:label="loc_oesx_ProceedsFromSaleofUnbilledContractsReceivable_2FE3D197418FB2DB6972130FA1627FAD" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_FF5167E410F67F0825FC12F4CE0074F5" xlink:to="loc_oesx_ProceedsFromSaleofUnbilledContractsReceivable_2FE3D197418FB2DB6972130FA1627FAD" xlink:type="arc" />
    <link:loc xlink:href="oesx-20180630.xsd#oesx_GainLossOnSaleOfUnbilledContractRevenue" xlink:label="loc_oesx_GainLossOnSaleOfUnbilledContractRevenue_9A97CDF6BB80AE36956F13119E7E5347" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_FF5167E410F67F0825FC12F4CE0074F5" xlink:to="loc_oesx_GainLossOnSaleOfUnbilledContractRevenue_9A97CDF6BB80AE36956F13119E7E5347" xlink:type="arc" />
    <link:loc xlink:href="oesx-20180630.xsd#oesx_UnbilledReceivables" xlink:label="loc_oesx_UnbilledReceivables_A65B4481EAAC821D4A8D12F4CE01428C" xlink:type="locator" />
    <link:presentationArc order="4" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_FF5167E410F67F0825FC12F4CE0074F5" xlink:to="loc_oesx_UnbilledReceivables_A65B4481EAAC821D4A8D12F4CE01428C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ContractWithCustomerLiability" xlink:label="loc_us-gaap_ContractWithCustomerLiability_2B69CD9E7CEA4917ADF612F4CE01ED74" xlink:type="locator" />
    <link:presentationArc order="5" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_FF5167E410F67F0825FC12F4CE0074F5" xlink:to="loc_us-gaap_ContractWithCustomerLiability_2B69CD9E7CEA4917ADF612F4CE01ED74" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_Revenues" xlink:label="loc_us-gaap_Revenues_3F38DE6BAB17F8DE3F0612F4CE01A5A7" xlink:type="locator" />
    <link:presentationArc order="6" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_FF5167E410F67F0825FC12F4CE0074F5" xlink:to="loc_us-gaap_Revenues_3F38DE6BAB17F8DE3F0612F4CE01A5A7" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.oesx.com/role/RevenueNotes" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RevenueFromContractWithCustomerAbstract" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerAbstract_CF643A386BD043657AA2CEFFC7E37FA5" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RevenueFromContractWithCustomerTextBlock" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerTextBlock_F01D5057E77A297B0DA3CF0030A04D31" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_RevenueFromContractWithCustomerAbstract_CF643A386BD043657AA2CEFFC7E37FA5" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerTextBlock_F01D5057E77A297B0DA3CF0030A04D31" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.oesx.com/role/RevenueSummaryOfContractAssetsAndLiabilitiesDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RevenueFromContractWithCustomerAbstract" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerAbstract_C740548C1535869B51AEFB23D333033F" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AccountsReceivableNet" xlink:label="loc_us-gaap_AccountsReceivableNet_D1E12ECA44D59E52BE69FB23D333F21E" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_RevenueFromContractWithCustomerAbstract_C740548C1535869B51AEFB23D333033F" xlink:to="loc_us-gaap_AccountsReceivableNet_D1E12ECA44D59E52BE69FB23D333F21E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ContractWithCustomerAssetNet" xlink:label="loc_us-gaap_ContractWithCustomerAssetNet_5CC1195E5949B2872DB4FB23D3348D93" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_RevenueFromContractWithCustomerAbstract_C740548C1535869B51AEFB23D333033F" xlink:to="loc_us-gaap_ContractWithCustomerAssetNet_5CC1195E5949B2872DB4FB23D3348D93" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ContractWithCustomerLiability" xlink:label="loc_us-gaap_ContractWithCustomerLiability_0E936AF698A38A4CEE4EFB23D334156F" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_RevenueFromContractWithCustomerAbstract_C740548C1535869B51AEFB23D333033F" xlink:to="loc_us-gaap_ContractWithCustomerLiability_0E936AF698A38A4CEE4EFB23D334156F" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.oesx.com/role/RevenueTables" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RevenueFromContractWithCustomerAbstract" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerAbstract_5D184AD4F12964AC6DB3F2F23CD4870B" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DisaggregationOfRevenueTableTextBlock" xlink:label="loc_us-gaap_DisaggregationOfRevenueTableTextBlock_73718070E8C5927235FBF36E127D323D" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_RevenueFromContractWithCustomerAbstract_5D184AD4F12964AC6DB3F2F23CD4870B" xlink:to="loc_us-gaap_DisaggregationOfRevenueTableTextBlock_73718070E8C5927235FBF36E127D323D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ContractWithCustomerAssetAndLiabilityTableTextBlock" xlink:label="loc_us-gaap_ContractWithCustomerAssetAndLiabilityTableTextBlock_CB3BE4DCE6DEB955C1AEF2F29CD2D00B" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_RevenueFromContractWithCustomerAbstract_5D184AD4F12964AC6DB3F2F23CD4870B" xlink:to="loc_us-gaap_ContractWithCustomerAssetAndLiabilityTableTextBlock_CB3BE4DCE6DEB955C1AEF2F29CD2D00B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfNewAccountingPronouncementsAndChangesInAccountingPrinciplesTextBlock" xlink:label="loc_us-gaap_ScheduleOfNewAccountingPronouncementsAndChangesInAccountingPrinciplesTextBlock_D3C6477F9D23B8A09F03F30290CBAEA9" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_RevenueFromContractWithCustomerAbstract_5D184AD4F12964AC6DB3F2F23CD4870B" xlink:to="loc_us-gaap_ScheduleOfNewAccountingPronouncementsAndChangesInAccountingPrinciplesTextBlock_D3C6477F9D23B8A09F03F30290CBAEA9" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.oesx.com/role/Segments" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SegmentReportingAbstract" xlink:label="loc_us-gaap_SegmentReportingAbstract_B50419CE87BF8E8FA23FCEEC11A9BC2F" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SegmentReportingDisclosureTextBlock" xlink:label="loc_us-gaap_SegmentReportingDisclosureTextBlock_8566FC32739BFF91275ACEEC11A91D4C" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_SegmentReportingAbstract_B50419CE87BF8E8FA23FCEEC11A9BC2F" xlink:to="loc_us-gaap_SegmentReportingDisclosureTextBlock_8566FC32739BFF91275ACEEC11A91D4C" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.oesx.com/role/SegmentsDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SegmentReportingAbstract" xlink:label="loc_us-gaap_SegmentReportingAbstract_02DC033FFCE0DC9DBF861457218B8AF8" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable" xlink:label="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_D8E9488299B25DCF071B1457218BBC30" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_SegmentReportingAbstract_02DC033FFCE0DC9DBF861457218B8AF8" xlink:to="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_D8E9488299B25DCF071B1457218BBC30" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidationItemsAxis" xlink:label="loc_us-gaap_ConsolidationItemsAxis_F348E2ACCF22252D71B61457218C012B" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_D8E9488299B25DCF071B1457218BBC30" xlink:to="loc_us-gaap_ConsolidationItemsAxis_F348E2ACCF22252D71B61457218C012B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidationItemsDomain" xlink:label="loc_us-gaap_ConsolidationItemsDomain_78631F22D4A7900E41CB1457218CE713" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ConsolidationItemsAxis_F348E2ACCF22252D71B61457218C012B" xlink:to="loc_us-gaap_ConsolidationItemsDomain_78631F22D4A7900E41CB1457218CE713" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OperatingSegmentsMember" xlink:label="loc_us-gaap_OperatingSegmentsMember_CD3D8D4346E423522D251457218CBC56" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ConsolidationItemsDomain_78631F22D4A7900E41CB1457218CE713" xlink:to="loc_us-gaap_OperatingSegmentsMember_CD3D8D4346E423522D251457218CBC56" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CorporateNonSegmentMember" xlink:label="loc_us-gaap_CorporateNonSegmentMember_3901F273E2C4A8CA08C31457218C06AF" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ConsolidationItemsDomain_78631F22D4A7900E41CB1457218CE713" xlink:to="loc_us-gaap_CorporateNonSegmentMember_3901F273E2C4A8CA08C31457218C06AF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementBusinessSegmentsAxis" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_E692D8E935376574AC161457218D1867" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_D8E9488299B25DCF071B1457218BBC30" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_E692D8E935376574AC161457218D1867" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SegmentDomain" xlink:label="loc_us-gaap_SegmentDomain_E77C50519FBF67B1AB681457218D23E2" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_E692D8E935376574AC161457218D1867" xlink:to="loc_us-gaap_SegmentDomain_E77C50519FBF67B1AB681457218D23E2" xlink:type="arc" />
    <link:loc xlink:href="oesx-20180630.xsd#oesx_EngineeredSystemsMember" xlink:label="loc_oesx_EngineeredSystemsMember_BEEE17BC72FE8BB484741457218D07A4" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_SegmentDomain_E77C50519FBF67B1AB681457218D23E2" xlink:to="loc_oesx_EngineeredSystemsMember_BEEE17BC72FE8BB484741457218D07A4" xlink:type="arc" />
    <link:loc xlink:href="oesx-20180630.xsd#oesx_DistributionServicesMember" xlink:label="loc_oesx_DistributionServicesMember_E59B299F1BA0F22B22351457218DE56F" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_SegmentDomain_E77C50519FBF67B1AB681457218D23E2" xlink:to="loc_oesx_DistributionServicesMember_E59B299F1BA0F22B22351457218DE56F" xlink:type="arc" />
    <link:loc xlink:href="oesx-20180630.xsd#oesx_U.S.MarketsMember" xlink:label="loc_oesx_U.S.MarketsMember_BC04FAA7521F84CE05C9145D3F338FA0" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_SegmentDomain_E77C50519FBF67B1AB681457218D23E2" xlink:to="loc_oesx_U.S.MarketsMember_BC04FAA7521F84CE05C9145D3F338FA0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SegmentReportingInformationLineItems" xlink:label="loc_us-gaap_SegmentReportingInformationLineItems_5623401FF4FA7DB75FBD1457218E5000" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_D8E9488299B25DCF071B1457218BBC30" xlink:to="loc_us-gaap_SegmentReportingInformationLineItems_5623401FF4FA7DB75FBD1457218E5000" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SegmentReportingInformationRevenueAbstract" xlink:label="loc_us-gaap_SegmentReportingInformationRevenueAbstract_BA8C86F55639825066541457218EA0CF" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_5623401FF4FA7DB75FBD1457218E5000" xlink:to="loc_us-gaap_SegmentReportingInformationRevenueAbstract_BA8C86F55639825066541457218EA0CF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_Revenues" xlink:label="loc_us-gaap_Revenues_50428FDFACB099C528BD1457218E04E9" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_SegmentReportingInformationRevenueAbstract_BA8C86F55639825066541457218EA0CF" xlink:to="loc_us-gaap_Revenues_50428FDFACB099C528BD1457218E04E9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OperatingIncomeLoss" xlink:label="loc_us-gaap_OperatingIncomeLoss_C55AF2AF8AC0E77198721457218E4D36" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_SegmentReportingInformationRevenueAbstract_BA8C86F55639825066541457218EA0CF" xlink:to="loc_us-gaap_OperatingIncomeLoss_C55AF2AF8AC0E77198721457218E4D36" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.oesx.com/role/SegmentsTables" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SegmentReportingAbstract" xlink:label="loc_us-gaap_SegmentReportingAbstract_AE68A9B79A1E5B5CA7E8D6865E3AE048" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfSegmentReportingInformationBySegmentTextBlock" xlink:label="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTextBlock_E285404763FE59098DF85E9F6C2075EA" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_SegmentReportingAbstract_AE68A9B79A1E5B5CA7E8D6865E3AE048" xlink:to="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTextBlock_E285404763FE59098DF85E9F6C2075EA" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.oesx.com/role/ShareholdersEquity" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StockholdersEquityNoteAbstract" xlink:label="loc_us-gaap_StockholdersEquityNoteAbstract_18D42A9D08EEABCC8690CEEC11DA411B" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StockholdersEquityNoteDisclosureTextBlock" xlink:label="loc_us-gaap_StockholdersEquityNoteDisclosureTextBlock_2B776474DF15F90C10EBCEEC11DA491F" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StockholdersEquityNoteAbstract_18D42A9D08EEABCC8690CEEC11DA411B" xlink:to="loc_us-gaap_StockholdersEquityNoteDisclosureTextBlock_2B776474DF15F90C10EBCEEC11DA491F" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.oesx.com/role/ShareholdersEquityDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StockholdersEquityNoteAbstract" xlink:label="loc_us-gaap_StockholdersEquityNoteAbstract_C9EC1A79E9EFE129D9591456B08A9FF2" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans_3F1D09B3D9AE84C4C6EF1456B08C9A04" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StockholdersEquityNoteAbstract_C9EC1A79E9EFE129D9591456B08A9FF2" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans_3F1D09B3D9AE84C4C6EF1456B08C9A04" xlink:type="arc" />
    <link:loc xlink:href="oesx-20180630.xsd#oesx_EmployeeStockPurchasePlanClosingMarketPriceOfSharesPurchased" xlink:label="loc_oesx_EmployeeStockPurchasePlanClosingMarketPriceOfSharesPurchased_A32A16367B1B7775FF701456B08C2C10" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StockholdersEquityNoteAbstract_C9EC1A79E9EFE129D9591456B08A9FF2" xlink:to="loc_oesx_EmployeeStockPurchasePlanClosingMarketPriceOfSharesPurchased_A32A16367B1B7775FF701456B08C2C10" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ReceivableFromShareholdersOrAffiliatesForIssuanceOfCapitalStock" xlink:label="loc_us-gaap_ReceivableFromShareholdersOrAffiliatesForIssuanceOfCapitalStock_FAB244658B9BA01608571456B08D8092" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StockholdersEquityNoteAbstract_C9EC1A79E9EFE129D9591456B08A9FF2" xlink:to="loc_us-gaap_ReceivableFromShareholdersOrAffiliatesForIssuanceOfCapitalStock_FAB244658B9BA01608571456B08D8092" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_TreasuryStockSharesAcquired" xlink:label="loc_us-gaap_TreasuryStockSharesAcquired_111DE5F39F84DD1A1A741456B08D19E1" xlink:type="locator" />
    <link:presentationArc order="4" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StockholdersEquityNoteAbstract_C9EC1A79E9EFE129D9591456B08A9FF2" xlink:to="loc_us-gaap_TreasuryStockSharesAcquired_111DE5F39F84DD1A1A741456B08D19E1" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.oesx.com/role/StockOptionsAndRestrictedShares" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract" xlink:label="loc_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_737B9752999E4DAF6EDDCEEC11CDD002" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DisclosureOfCompensationRelatedCostsShareBasedPaymentsTextBlock" xlink:label="loc_us-gaap_DisclosureOfCompensationRelatedCostsShareBasedPaymentsTextBlock_6696DDDCC30B800E3CDFCEEC11CDEB46" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_737B9752999E4DAF6EDDCEEC11CDD002" xlink:to="loc_us-gaap_DisclosureOfCompensationRelatedCostsShareBasedPaymentsTextBlock_6696DDDCC30B800E3CDFCEEC11CDEB46" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.oesx.com/role/StockOptionsAndRestrictedSharesNarrativeDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract" xlink:label="loc_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_376C9BC8FB4F5683AA6ACC1499524BDF" xlink:type="locator" />
    <link:loc xlink:href="oesx-20180630.xsd#oesx_DeferredCompensationArrangementWithIndividualCompensationExpensePeriodOfRecognition" xlink:label="loc_oesx_DeferredCompensationArrangementWithIndividualCompensationExpensePeriodOfRecognition_8FE1379144035737ADBACF1A25289697" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_376C9BC8FB4F5683AA6ACC1499524BDF" xlink:to="loc_oesx_DeferredCompensationArrangementWithIndividualCompensationExpensePeriodOfRecognition_8FE1379144035737ADBACF1A25289697" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DeferredCompensationArrangementWithIndividualCompensationExpense" xlink:label="loc_us-gaap_DeferredCompensationArrangementWithIndividualCompensationExpense_81DCD3C8F75E50E5B2AE9DF75ED5C14F" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_376C9BC8FB4F5683AA6ACC1499524BDF" xlink:to="loc_us-gaap_DeferredCompensationArrangementWithIndividualCompensationExpense_81DCD3C8F75E50E5B2AE9DF75ED5C14F" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.oesx.com/role/StockOptionsAndRestrictedSharesRestrictedSharesAndStockOptionsDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract" xlink:label="loc_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_1536C80CE766505A57FACEEC11BC6E91" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_266FCA3CEFD8CB8FE65ECEEC11BC0CC1" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_1536C80CE766505A57FACEEC11BC6E91" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_266FCA3CEFD8CB8FE65ECEEC11BC0CC1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AwardTypeAxis" xlink:label="loc_us-gaap_AwardTypeAxis_20A3B03746048D2D0F37CEEC11BC1C7E" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_266FCA3CEFD8CB8FE65ECEEC11BC0CC1" xlink:to="loc_us-gaap_AwardTypeAxis_20A3B03746048D2D0F37CEEC11BC1C7E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_CA89EFF69CD9AAB300DDCEEC11BCA973" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AwardTypeAxis_20A3B03746048D2D0F37CEEC11BC1C7E" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_CA89EFF69CD9AAB300DDCEEC11BCA973" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RestrictedStockMember" xlink:label="loc_us-gaap_RestrictedStockMember_68672638050480DD9609CEEC11BC23C9" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_CA89EFF69CD9AAB300DDCEEC11BCA973" xlink:to="loc_us-gaap_RestrictedStockMember_68672638050480DD9609CEEC11BC23C9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RangeAxis" xlink:label="loc_us-gaap_RangeAxis_BF46FCC749D47C2624E1CEEC11BDCB1D" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_266FCA3CEFD8CB8FE65ECEEC11BC0CC1" xlink:to="loc_us-gaap_RangeAxis_BF46FCC749D47C2624E1CEEC11BDCB1D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RangeMember" xlink:label="loc_us-gaap_RangeMember_40F7A559598259993F13CEEC11BD35B6" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_RangeAxis_BF46FCC749D47C2624E1CEEC11BDCB1D" xlink:to="loc_us-gaap_RangeMember_40F7A559598259993F13CEEC11BD35B6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_MinimumMember" xlink:label="loc_us-gaap_MinimumMember_5E3F31C95445C20CCC4CCEEC11BD1869" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_RangeMember_40F7A559598259993F13CEEC11BD35B6" xlink:to="loc_us-gaap_MinimumMember_5E3F31C95445C20CCC4CCEEC11BD1869" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_MaximumMember" xlink:label="loc_us-gaap_MaximumMember_FEC5C1530654500BABEECEEC11BD1A47" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_RangeMember_40F7A559598259993F13CEEC11BD35B6" xlink:to="loc_us-gaap_MaximumMember_FEC5C1530654500BABEECEEC11BD1A47" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_B5288ECDE927B9CEFD8ECEEC11BE36DE" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_266FCA3CEFD8CB8FE65ECEEC11BC0CC1" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_B5288ECDE927B9CEFD8ECEEC11BE36DE" xlink:type="arc" />
    <link:loc xlink:href="oesx-20180630.xsd#oesx_RestrictedSharesIssuedToKeyEmployeesAbstract" xlink:label="loc_oesx_RestrictedSharesIssuedToKeyEmployeesAbstract_0121119306C6D4DE87C2CEEC11BED4AE" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_B5288ECDE927B9CEFD8ECEEC11BE36DE" xlink:to="loc_oesx_RestrictedSharesIssuedToKeyEmployeesAbstract_0121119306C6D4DE87C2CEEC11BED4AE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_153ABC9E076850C5D203CEEC11BE6A06" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/periodStartLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_oesx_RestrictedSharesIssuedToKeyEmployeesAbstract_0121119306C6D4DE87C2CEEC11BED4AE" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_153ABC9E076850C5D203CEEC11BE6A06" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_8CE797526F557B150706CEEC11BE50EA" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_oesx_RestrictedSharesIssuedToKeyEmployeesAbstract_0121119306C6D4DE87C2CEEC11BED4AE" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_8CE797526F557B150706CEEC11BE50EA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_C7C46EF7E92C58B03269CEEC11BEA150" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_oesx_RestrictedSharesIssuedToKeyEmployeesAbstract_0121119306C6D4DE87C2CEEC11BED4AE" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_C7C46EF7E92C58B03269CEEC11BEA150" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_56FE249B1727FFAC5639CEEC11BE5635" xlink:type="locator" />
    <link:presentationArc order="4" preferredLabel="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_oesx_RestrictedSharesIssuedToKeyEmployeesAbstract_0121119306C6D4DE87C2CEEC11BED4AE" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_56FE249B1727FFAC5639CEEC11BE5635" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_167E41A1317E9B003E8ECEEC11BF65ED" xlink:type="locator" />
    <link:presentationArc order="5" preferredLabel="http://www.xbrl.org/2003/role/periodEndLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_oesx_RestrictedSharesIssuedToKeyEmployeesAbstract_0121119306C6D4DE87C2CEEC11BED4AE" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_167E41A1317E9B003E8ECEEC11BF65ED" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_04A77542F9E5DF2CE0FECEEC11BFE96B" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_B5288ECDE927B9CEFD8ECEEC11BE36DE" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_04A77542F9E5DF2CE0FECEEC11BFE96B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedNumberOfSharesRollForward" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedNumberOfSharesRollForward_C8ECE0E9321655A6C8DDCEEC11BFCBA6" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_B5288ECDE927B9CEFD8ECEEC11BE36DE" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedNumberOfSharesRollForward_C8ECE0E9321655A6C8DDCEEC11BFCBA6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedNumberOfShares" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedNumberOfShares_6CE7D1A2F8EE578CC3DBCEEC11BFB29A" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/periodStartLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedNumberOfSharesRollForward_C8ECE0E9321655A6C8DDCEEC11BFCBA6" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedNumberOfShares_6CE7D1A2F8EE578CC3DBCEEC11BFB29A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross_026C6ACE3B3205CE357DCEEC11BF0379" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedNumberOfSharesRollForward_C8ECE0E9321655A6C8DDCEEC11BFCBA6" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross_026C6ACE3B3205CE357DCEEC11BF0379" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedNumberOfShares" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedNumberOfShares_615F6C15615DF552747ACEEC11C0E035" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedNumberOfSharesRollForward_C8ECE0E9321655A6C8DDCEEC11BFCBA6" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedNumberOfShares_615F6C15615DF552747ACEEC11C0E035" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedOptionsForfeitedNumberOfShares" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedOptionsForfeitedNumberOfShares_0CEACAE0A79E7DF2382ACEEC11C04BD7" xlink:type="locator" />
    <link:presentationArc order="4" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedNumberOfSharesRollForward_C8ECE0E9321655A6C8DDCEEC11BFCBA6" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedOptionsForfeitedNumberOfShares_0CEACAE0A79E7DF2382ACEEC11C04BD7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedNumberOfShares" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedNumberOfShares_5813F39404BDCC8E5E7FCEEC11C0E442" xlink:type="locator" />
    <link:presentationArc order="5" preferredLabel="http://www.xbrl.org/2003/role/periodEndLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedNumberOfSharesRollForward_C8ECE0E9321655A6C8DDCEEC11BFCBA6" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedNumberOfShares_5813F39404BDCC8E5E7FCEEC11C0E442" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice_541A96CB467F72993BCDCEEC11C0FCEB" xlink:type="locator" />
    <link:presentationArc order="4" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_B5288ECDE927B9CEFD8ECEEC11BE36DE" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice_541A96CB467F72993BCDCEEC11C0FCEB" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.oesx.com/role/StockOptionsAndRestrictedSharesStockBasedCompensationDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract" xlink:label="loc_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_B8E32D848A3082249426CEEC11C41549" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable" xlink:label="loc_us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable_B31FE9A1873A8A21ABFBCEEC11C5DE81" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_B8E32D848A3082249426CEEC11C41549" xlink:to="loc_us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable_B31FE9A1873A8A21ABFBCEEC11C5DE81" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncomeStatementLocationAxis" xlink:label="loc_us-gaap_IncomeStatementLocationAxis_13EC45C0290D80FBCAE0CEEC11C576AB" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable_B31FE9A1873A8A21ABFBCEEC11C5DE81" xlink:to="loc_us-gaap_IncomeStatementLocationAxis_13EC45C0290D80FBCAE0CEEC11C576AB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncomeStatementLocationDomain" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_DE37576DC0CD91319CF4CEEC11C5B5F7" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_13EC45C0290D80FBCAE0CEEC11C576AB" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_DE37576DC0CD91319CF4CEEC11C5B5F7" xlink:type="arc" />
    <link:loc xlink:href="oesx-20180630.xsd#oesx_CostOfProductsMember" xlink:label="loc_oesx_CostOfProductsMember_D3ADA9A2BC6732DEAC68CF4B8D3FD826" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_DE37576DC0CD91319CF4CEEC11C5B5F7" xlink:to="loc_oesx_CostOfProductsMember_D3ADA9A2BC6732DEAC68CF4B8D3FD826" xlink:type="arc" />
    <link:loc xlink:href="oesx-20180630.xsd#oesx_CostOfServicesMember" xlink:label="loc_oesx_CostOfServicesMember_B39771550A43B5E3D073CF4BE8DD3862" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_DE37576DC0CD91319CF4CEEC11C5B5F7" xlink:to="loc_oesx_CostOfServicesMember_B39771550A43B5E3D073CF4BE8DD3862" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_GeneralAndAdministrativeExpenseMember" xlink:label="loc_us-gaap_GeneralAndAdministrativeExpenseMember_44786309E04D6EF344B9CEEC11C66975" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_DE37576DC0CD91319CF4CEEC11C5B5F7" xlink:to="loc_us-gaap_GeneralAndAdministrativeExpenseMember_44786309E04D6EF344B9CEEC11C66975" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SellingAndMarketingExpenseMember" xlink:label="loc_us-gaap_SellingAndMarketingExpenseMember_DACD12C5115519B93636CEEC11C6F87D" xlink:type="locator" />
    <link:presentationArc order="4" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_DE37576DC0CD91319CF4CEEC11C5B5F7" xlink:to="loc_us-gaap_SellingAndMarketingExpenseMember_DACD12C5115519B93636CEEC11C6F87D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ResearchAndDevelopmentExpenseMember" xlink:label="loc_us-gaap_ResearchAndDevelopmentExpenseMember_1F826F02BEE556962A1BCEEC11C62069" xlink:type="locator" />
    <link:presentationArc order="5" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_DE37576DC0CD91319CF4CEEC11C5B5F7" xlink:to="loc_us-gaap_ResearchAndDevelopmentExpenseMember_1F826F02BEE556962A1BCEEC11C62069" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems_0BC199BF0D0BACDBB03DCEEC11C6AE5C" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable_B31FE9A1873A8A21ABFBCEEC11C5DE81" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems_0BC199BF0D0BACDBB03DCEEC11C6AE5C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareBasedCompensationAllocationAndClassificationInFinancialStatementsAbstract" xlink:label="loc_us-gaap_ShareBasedCompensationAllocationAndClassificationInFinancialStatementsAbstract_7D6852FB70E7E8DFE521CEEC11C68B9E" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems_0BC199BF0D0BACDBB03DCEEC11C6AE5C" xlink:to="loc_us-gaap_ShareBasedCompensationAllocationAndClassificationInFinancialStatementsAbstract_7D6852FB70E7E8DFE521CEEC11C68B9E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AllocatedShareBasedCompensationExpense" xlink:label="loc_us-gaap_AllocatedShareBasedCompensationExpense_4A35984B8890C79F996ECEEC11C7E65A" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2009/role/netLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationAllocationAndClassificationInFinancialStatementsAbstract_7D6852FB70E7E8DFE521CEEC11C68B9E" xlink:to="loc_us-gaap_AllocatedShareBasedCompensationExpense_4A35984B8890C79F996ECEEC11C7E65A" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.oesx.com/role/StockOptionsAndRestrictedSharesTables" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract" xlink:label="loc_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_118D6063B2B05C948538B0F46AE230C2" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTextBlock" xlink:label="loc_us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTextBlock_34A6E17BDCAD5A76AE21B085E5E7DABC" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_118D6063B2B05C948538B0F46AE230C2" xlink:to="loc_us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTextBlock_34A6E17BDCAD5A76AE21B085E5E7DABC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfNonvestedShareActivityTableTextBlock" xlink:label="loc_us-gaap_ScheduleOfNonvestedShareActivityTableTextBlock_5698B6409ED3543283098F89A83FFD53" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_118D6063B2B05C948538B0F46AE230C2" xlink:to="loc_us-gaap_ScheduleOfNonvestedShareActivityTableTextBlock_5698B6409ED3543283098F89A83FFD53" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfSharebasedCompensationRestrictedStockAndRestrictedStockUnitsActivityTableTextBlock" xlink:label="loc_us-gaap_ScheduleOfSharebasedCompensationRestrictedStockAndRestrictedStockUnitsActivityTableTextBlock_56863CF6F0EA55D28934AA0A44756A5B" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_118D6063B2B05C948538B0F46AE230C2" xlink:to="loc_us-gaap_ScheduleOfSharebasedCompensationRestrictedStockAndRestrictedStockUnitsActivityTableTextBlock_56863CF6F0EA55D28934AA0A44756A5B" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.oesx.com/role/SubsequentEvents" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SubsequentEventsAbstract" xlink:label="loc_us-gaap_SubsequentEventsAbstract_742BB91FDD9E654856F7CEEC117A2A8C" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SubsequentEventsTextBlock" xlink:label="loc_us-gaap_SubsequentEventsTextBlock_5DB67928F14A63C6677ECEEC117D3D3F" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_SubsequentEventsAbstract_742BB91FDD9E654856F7CEEC117A2A8C" xlink:to="loc_us-gaap_SubsequentEventsTextBlock_5DB67928F14A63C6677ECEEC117D3D3F" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.oesx.com/role/SummaryOfSignificantAccountingPolicies" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AccountingPoliciesAbstract" xlink:label="loc_us-gaap_AccountingPoliciesAbstract_77FBA8C67F69580DAAB2D7A8AC75DFD5" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SignificantAccountingPoliciesTextBlock" xlink:label="loc_us-gaap_SignificantAccountingPoliciesTextBlock_83A4625357A55F1496769706A25A8B6A" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AccountingPoliciesAbstract_77FBA8C67F69580DAAB2D7A8AC75DFD5" xlink:to="loc_us-gaap_SignificantAccountingPoliciesTextBlock_83A4625357A55F1496769706A25A8B6A" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.oesx.com/role/SummaryOfSignificantAccountingPoliciesDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AccountingPoliciesAbstract" xlink:label="loc_us-gaap_AccountingPoliciesAbstract_A11ABC19FB028E64EF36CEEC132744EB" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConcentrationRiskTable" xlink:label="loc_us-gaap_ConcentrationRiskTable_8C7C3F3BA3C84CD8C512CEEC1327D9B9" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AccountingPoliciesAbstract_A11ABC19FB028E64EF36CEEC132744EB" xlink:to="loc_us-gaap_ConcentrationRiskTable_8C7C3F3BA3C84CD8C512CEEC1327D9B9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConcentrationRiskByBenchmarkAxis" xlink:label="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_998B9497527FAF4E96F3CEEC1328F3A2" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ConcentrationRiskTable_8C7C3F3BA3C84CD8C512CEEC1327D9B9" xlink:to="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_998B9497527FAF4E96F3CEEC1328F3A2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConcentrationRiskBenchmarkDomain" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_9F3AA91694DCE3265C2FCEEC13291615" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_998B9497527FAF4E96F3CEEC1328F3A2" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_9F3AA91694DCE3265C2FCEEC13291615" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CostOfGoodsTotalMember" xlink:label="loc_us-gaap_CostOfGoodsTotalMember_D347798A391E18407AA8CEEC1329AFED" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ConcentrationRiskBenchmarkDomain_9F3AA91694DCE3265C2FCEEC13291615" xlink:to="loc_us-gaap_CostOfGoodsTotalMember_D347798A391E18407AA8CEEC1329AFED" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SalesRevenueNetMember" xlink:label="loc_us-gaap_SalesRevenueNetMember_98EDA042327BBEA09B48CEEC1329A606" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ConcentrationRiskBenchmarkDomain_9F3AA91694DCE3265C2FCEEC13291615" xlink:to="loc_us-gaap_SalesRevenueNetMember_98EDA042327BBEA09B48CEEC1329A606" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AccountsReceivableMember" xlink:label="loc_us-gaap_AccountsReceivableMember_CA9E0242CAB3694E4364CEEC13299CAD" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ConcentrationRiskBenchmarkDomain_9F3AA91694DCE3265C2FCEEC13291615" xlink:to="loc_us-gaap_AccountsReceivableMember_CA9E0242CAB3694E4364CEEC13299CAD" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConcentrationRiskByTypeAxis" xlink:label="loc_us-gaap_ConcentrationRiskByTypeAxis_5584B953BE27FFF85430CEEC132A7B4E" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ConcentrationRiskTable_8C7C3F3BA3C84CD8C512CEEC1327D9B9" xlink:to="loc_us-gaap_ConcentrationRiskByTypeAxis_5584B953BE27FFF85430CEEC132A7B4E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConcentrationRiskTypeDomain" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_0C105C78D54D6FBC7922CEEC132AA6EF" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_5584B953BE27FFF85430CEEC132A7B4E" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_0C105C78D54D6FBC7922CEEC132AA6EF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CustomerConcentrationRiskMember" xlink:label="loc_us-gaap_CustomerConcentrationRiskMember_DAB11F309B0B7B52AACBCEEC132AD688" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ConcentrationRiskTypeDomain_0C105C78D54D6FBC7922CEEC132AA6EF" xlink:to="loc_us-gaap_CustomerConcentrationRiskMember_DAB11F309B0B7B52AACBCEEC132AD688" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_MajorCustomersAxis" xlink:label="loc_us-gaap_MajorCustomersAxis_9157C3B52F28411190FACEEC132AEE5D" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ConcentrationRiskTable_8C7C3F3BA3C84CD8C512CEEC1327D9B9" xlink:to="loc_us-gaap_MajorCustomersAxis_9157C3B52F28411190FACEEC132AEE5D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NameOfMajorCustomerDomain" xlink:label="loc_us-gaap_NameOfMajorCustomerDomain_0EC8B6C022D64DF484FECEEC132A4A63" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_MajorCustomersAxis_9157C3B52F28411190FACEEC132AEE5D" xlink:to="loc_us-gaap_NameOfMajorCustomerDomain_0EC8B6C022D64DF484FECEEC132A4A63" xlink:type="arc" />
    <link:loc xlink:href="oesx-20180630.xsd#oesx_CustomerOneMember" xlink:label="loc_oesx_CustomerOneMember_0910BDDC8D488735CBB6CEEC132B2F4D" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_NameOfMajorCustomerDomain_0EC8B6C022D64DF484FECEEC132A4A63" xlink:to="loc_oesx_CustomerOneMember_0910BDDC8D488735CBB6CEEC132B2F4D" xlink:type="arc" />
    <link:loc xlink:href="oesx-20180630.xsd#oesx_CustomerTwoMember" xlink:label="loc_oesx_CustomerTwoMember_1628532F8F74948B0C96CEEC132C464A" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_NameOfMajorCustomerDomain_0EC8B6C022D64DF484FECEEC132A4A63" xlink:to="loc_oesx_CustomerTwoMember_1628532F8F74948B0C96CEEC132C464A" xlink:type="arc" />
    <link:loc xlink:href="oesx-20180630.xsd#oesx_CustomerThreeMember" xlink:label="loc_oesx_CustomerThreeMember_5C98AA4369721492A2F0CEEC132C3908" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_NameOfMajorCustomerDomain_0EC8B6C022D64DF484FECEEC132A4A63" xlink:to="loc_oesx_CustomerThreeMember_5C98AA4369721492A2F0CEEC132C3908" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConcentrationRiskLineItems" xlink:label="loc_us-gaap_ConcentrationRiskLineItems_85B3B5737D541E0D552BCEEC132C043D" xlink:type="locator" />
    <link:presentationArc order="4" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ConcentrationRiskTable_8C7C3F3BA3C84CD8C512CEEC1327D9B9" xlink:to="loc_us-gaap_ConcentrationRiskLineItems_85B3B5737D541E0D552BCEEC132C043D" xlink:type="arc" />
    <link:loc xlink:href="oesx-20180630.xsd#oesx_NumberOfFinancialInstitutions" xlink:label="loc_oesx_NumberOfFinancialInstitutions_4B4371081C02249C58E7CEEC132CAB1D" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ConcentrationRiskLineItems_85B3B5737D541E0D552BCEEC132C043D" xlink:to="loc_oesx_NumberOfFinancialInstitutions_4B4371081C02249C58E7CEEC132CAB1D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConcentrationRiskPercentage1" xlink:label="loc_us-gaap_ConcentrationRiskPercentage1_8C643F8F61FB147B4400CEEC132CDB65" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ConcentrationRiskLineItems_85B3B5737D541E0D552BCEEC132C043D" xlink:to="loc_us-gaap_ConcentrationRiskPercentage1_8C643F8F61FB147B4400CEEC132CDB65" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.oesx.com/role/SummaryOfSignificantAccountingPoliciesPolicies" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AccountingPoliciesAbstract" xlink:label="loc_us-gaap_AccountingPoliciesAbstract_B400B3D68A785952B6A3809C9A2B47F8" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidationPolicyTextBlock" xlink:label="loc_us-gaap_ConsolidationPolicyTextBlock_2E2D3256DC5D5629B709C07C3B4C9C83" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AccountingPoliciesAbstract_B400B3D68A785952B6A3809C9A2B47F8" xlink:to="loc_us-gaap_ConsolidationPolicyTextBlock_2E2D3256DC5D5629B709C07C3B4C9C83" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BasisOfAccountingPolicyPolicyTextBlock" xlink:label="loc_us-gaap_BasisOfAccountingPolicyPolicyTextBlock_A3A35F8136C15362B8C2F68760328BAF" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AccountingPoliciesAbstract_B400B3D68A785952B6A3809C9A2B47F8" xlink:to="loc_us-gaap_BasisOfAccountingPolicyPolicyTextBlock_A3A35F8136C15362B8C2F68760328BAF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_UseOfEstimates" xlink:label="loc_us-gaap_UseOfEstimates_9BC4F85795F858C3B48028FC3BA664F4" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AccountingPoliciesAbstract_B400B3D68A785952B6A3809C9A2B47F8" xlink:to="loc_us-gaap_UseOfEstimates_9BC4F85795F858C3B48028FC3BA664F4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConcentrationRiskCreditRisk" xlink:label="loc_us-gaap_ConcentrationRiskCreditRisk_8AADDC4AC58558ABB5D4D7AE0EB4F774" xlink:type="locator" />
    <link:presentationArc order="4" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AccountingPoliciesAbstract_B400B3D68A785952B6A3809C9A2B47F8" xlink:to="loc_us-gaap_ConcentrationRiskCreditRisk_8AADDC4AC58558ABB5D4D7AE0EB4F774" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NewAccountingPronouncementsPolicyPolicyTextBlock" xlink:label="loc_us-gaap_NewAccountingPronouncementsPolicyPolicyTextBlock_9D3007F0C99E5035A244C106C8E22399" xlink:type="locator" />
    <link:presentationArc order="5" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AccountingPoliciesAbstract_B400B3D68A785952B6A3809C9A2B47F8" xlink:to="loc_us-gaap_NewAccountingPronouncementsPolicyPolicyTextBlock_9D3007F0C99E5035A244C106C8E22399" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.oesx.com/role/UnauditedCondensedConsolidatedBalanceSheets" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementOfFinancialPositionAbstract" xlink:label="loc_us-gaap_StatementOfFinancialPositionAbstract_9EB01CD9F910FD884023F2A6B134CE9E" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AssetsAbstract" xlink:label="loc_us-gaap_AssetsAbstract_87590EC4BCC85E6992F3F2A6B1367020" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfFinancialPositionAbstract_9EB01CD9F910FD884023F2A6B134CE9E" xlink:to="loc_us-gaap_AssetsAbstract_87590EC4BCC85E6992F3F2A6B1367020" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:label="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_E59C496F8F4830B31DBBF2A6B138C9B8" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AssetsAbstract_87590EC4BCC85E6992F3F2A6B1367020" xlink:to="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_E59C496F8F4830B31DBBF2A6B138C9B8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AccountsReceivableNetCurrent" xlink:label="loc_us-gaap_AccountsReceivableNetCurrent_ED516A97C62671271727F2A6B1397CB3" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AssetsAbstract_87590EC4BCC85E6992F3F2A6B1367020" xlink:to="loc_us-gaap_AccountsReceivableNetCurrent_ED516A97C62671271727F2A6B1397CB3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_UnbilledContractsReceivable" xlink:label="loc_us-gaap_UnbilledContractsReceivable_9C9C781DE4D820431170F2A6B1397AB6" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AssetsAbstract_87590EC4BCC85E6992F3F2A6B1367020" xlink:to="loc_us-gaap_UnbilledContractsReceivable_9C9C781DE4D820431170F2A6B1397AB6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_InventoryNet" xlink:label="loc_us-gaap_InventoryNet_DA6DB11C7F9156FDBF15F2A6B1398D62" xlink:type="locator" />
    <link:presentationArc order="4" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AssetsAbstract_87590EC4BCC85E6992F3F2A6B1367020" xlink:to="loc_us-gaap_InventoryNet_DA6DB11C7F9156FDBF15F2A6B1398D62" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DeferredCostsCurrent" xlink:label="loc_us-gaap_DeferredCostsCurrent_AC1E1652A79868F8F13DF2A6B13971D7" xlink:type="locator" />
    <link:presentationArc order="5" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AssetsAbstract_87590EC4BCC85E6992F3F2A6B1367020" xlink:to="loc_us-gaap_DeferredCostsCurrent_AC1E1652A79868F8F13DF2A6B13971D7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PrepaidExpenseAndOtherAssetsCurrent" xlink:label="loc_us-gaap_PrepaidExpenseAndOtherAssetsCurrent_094AD5A87352ED439109F2A6B13A6228" xlink:type="locator" />
    <link:presentationArc order="6" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AssetsAbstract_87590EC4BCC85E6992F3F2A6B1367020" xlink:to="loc_us-gaap_PrepaidExpenseAndOtherAssetsCurrent_094AD5A87352ED439109F2A6B13A6228" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AssetsCurrent" xlink:label="loc_us-gaap_AssetsCurrent_D8C93D81E65E6E0B1EF2F2A6B13AFEA4" xlink:type="locator" />
    <link:presentationArc order="7" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AssetsAbstract_87590EC4BCC85E6992F3F2A6B1367020" xlink:to="loc_us-gaap_AssetsCurrent_D8C93D81E65E6E0B1EF2F2A6B13AFEA4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PropertyPlantAndEquipmentNet" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentNet_6C52F29B376AA11FDFB5F2A6B13A3844" xlink:type="locator" />
    <link:presentationArc order="8" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AssetsAbstract_87590EC4BCC85E6992F3F2A6B1367020" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentNet_6C52F29B376AA11FDFB5F2A6B13A3844" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IntangibleAssetsNetExcludingGoodwill" xlink:label="loc_us-gaap_IntangibleAssetsNetExcludingGoodwill_1EC97FF88A09D51B4BEAF2A6B13AD0B1" xlink:type="locator" />
    <link:presentationArc order="9" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AssetsAbstract_87590EC4BCC85E6992F3F2A6B1367020" xlink:to="loc_us-gaap_IntangibleAssetsNetExcludingGoodwill_1EC97FF88A09D51B4BEAF2A6B13AD0B1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherAssetsNoncurrent" xlink:label="loc_us-gaap_OtherAssetsNoncurrent_4791068CB820862BDDB1F2A6B13AE89D" xlink:type="locator" />
    <link:presentationArc order="10" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AssetsAbstract_87590EC4BCC85E6992F3F2A6B1367020" xlink:to="loc_us-gaap_OtherAssetsNoncurrent_4791068CB820862BDDB1F2A6B13AE89D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_Assets" xlink:label="loc_us-gaap_Assets_A9E89610ED073FD8AA73F2A6B13B6E6E" xlink:type="locator" />
    <link:presentationArc order="11" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AssetsAbstract_87590EC4BCC85E6992F3F2A6B1367020" xlink:to="loc_us-gaap_Assets_A9E89610ED073FD8AA73F2A6B13B6E6E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LiabilitiesAndStockholdersEquityAbstract" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_C46257078396D13912AEF2A6B13BCD41" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfFinancialPositionAbstract_9EB01CD9F910FD884023F2A6B134CE9E" xlink:to="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_C46257078396D13912AEF2A6B13BCD41" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AccountsPayableCurrent" xlink:label="loc_us-gaap_AccountsPayableCurrent_C1FF54C964DDFAE87E5FF2A6B13BB673" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_C46257078396D13912AEF2A6B13BCD41" xlink:to="loc_us-gaap_AccountsPayableCurrent_C1FF54C964DDFAE87E5FF2A6B13BB673" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AccruedLiabilitiesCurrent" xlink:label="loc_us-gaap_AccruedLiabilitiesCurrent_6DE54F46F9DF4DC093D9F2A6B13B06DF" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_C46257078396D13912AEF2A6B13BCD41" xlink:to="loc_us-gaap_AccruedLiabilitiesCurrent_6DE54F46F9DF4DC093D9F2A6B13B06DF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ContractWithCustomerLiabilityCurrent" xlink:label="loc_us-gaap_ContractWithCustomerLiabilityCurrent_2E4F7D242099D6688416F2A6B13B1283" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_C46257078396D13912AEF2A6B13BCD41" xlink:to="loc_us-gaap_ContractWithCustomerLiabilityCurrent_2E4F7D242099D6688416F2A6B13B1283" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LongTermDebtCurrent" xlink:label="loc_us-gaap_LongTermDebtCurrent_DFBC84EED7AA50A93C55F2A6B13CEE5E" xlink:type="locator" />
    <link:presentationArc order="4" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_C46257078396D13912AEF2A6B13BCD41" xlink:to="loc_us-gaap_LongTermDebtCurrent_DFBC84EED7AA50A93C55F2A6B13CEE5E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LiabilitiesCurrent" xlink:label="loc_us-gaap_LiabilitiesCurrent_09DC91CFD1E801971446F2A6B13C7429" xlink:type="locator" />
    <link:presentationArc order="5" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_C46257078396D13912AEF2A6B13BCD41" xlink:to="loc_us-gaap_LiabilitiesCurrent_09DC91CFD1E801971446F2A6B13C7429" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LongTermLineOfCredit" xlink:label="loc_us-gaap_LongTermLineOfCredit_8BB2DFC90FCC16D2CC6EF2A6B13C7017" xlink:type="locator" />
    <link:presentationArc order="6" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_C46257078396D13912AEF2A6B13BCD41" xlink:to="loc_us-gaap_LongTermLineOfCredit_8BB2DFC90FCC16D2CC6EF2A6B13C7017" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherLongTermDebtNoncurrent" xlink:label="loc_us-gaap_OtherLongTermDebtNoncurrent_7A359774024467158800F2A6B13C195F" xlink:type="locator" />
    <link:presentationArc order="7" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_C46257078396D13912AEF2A6B13BCD41" xlink:to="loc_us-gaap_OtherLongTermDebtNoncurrent_7A359774024467158800F2A6B13C195F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ContractWithCustomerLiabilityNoncurrent" xlink:label="loc_us-gaap_ContractWithCustomerLiabilityNoncurrent_EE22CB37A5E43B1DC22BF2A6B13CE56F" xlink:type="locator" />
    <link:presentationArc order="8" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_C46257078396D13912AEF2A6B13BCD41" xlink:to="loc_us-gaap_ContractWithCustomerLiabilityNoncurrent_EE22CB37A5E43B1DC22BF2A6B13CE56F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherLiabilitiesNoncurrent" xlink:label="loc_us-gaap_OtherLiabilitiesNoncurrent_2C4AAC7D1359B94E6199F2A6B13CD53F" xlink:type="locator" />
    <link:presentationArc order="9" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_C46257078396D13912AEF2A6B13BCD41" xlink:to="loc_us-gaap_OtherLiabilitiesNoncurrent_2C4AAC7D1359B94E6199F2A6B13CD53F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_Liabilities" xlink:label="loc_us-gaap_Liabilities_C9D69070DF745A49985DF2A6B13C641C" xlink:type="locator" />
    <link:presentationArc order="10" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_C46257078396D13912AEF2A6B13BCD41" xlink:to="loc_us-gaap_Liabilities_C9D69070DF745A49985DF2A6B13C641C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CommitmentsAndContingencies" xlink:label="loc_us-gaap_CommitmentsAndContingencies_BFBC7E6F7D23104ACED6F2A6B13D95D8" xlink:type="locator" />
    <link:presentationArc order="11" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_C46257078396D13912AEF2A6B13BCD41" xlink:to="loc_us-gaap_CommitmentsAndContingencies_BFBC7E6F7D23104ACED6F2A6B13D95D8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StockholdersEquityAbstract" xlink:label="loc_us-gaap_StockholdersEquityAbstract_CAC5E9ABF769262D0C4DF2A6B13D210B" xlink:type="locator" />
    <link:presentationArc order="12" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_C46257078396D13912AEF2A6B13BCD41" xlink:to="loc_us-gaap_StockholdersEquityAbstract_CAC5E9ABF769262D0C4DF2A6B13D210B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PreferredStockValue" xlink:label="loc_us-gaap_PreferredStockValue_2163B14C55D00D8FA365F2A6B13D4C84" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StockholdersEquityAbstract_CAC5E9ABF769262D0C4DF2A6B13D210B" xlink:to="loc_us-gaap_PreferredStockValue_2163B14C55D00D8FA365F2A6B13D4C84" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CommonStockValue" xlink:label="loc_us-gaap_CommonStockValue_03CC8BBDBFA9EAE89DCDF2A6B13DEF25" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StockholdersEquityAbstract_CAC5E9ABF769262D0C4DF2A6B13D210B" xlink:to="loc_us-gaap_CommonStockValue_03CC8BBDBFA9EAE89DCDF2A6B13DEF25" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AdditionalPaidInCapital" xlink:label="loc_us-gaap_AdditionalPaidInCapital_6626A3EECF7168B13A70F2A6B13D05E9" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StockholdersEquityAbstract_CAC5E9ABF769262D0C4DF2A6B13D210B" xlink:to="loc_us-gaap_AdditionalPaidInCapital_6626A3EECF7168B13A70F2A6B13D05E9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_TreasuryStockValue" xlink:label="loc_us-gaap_TreasuryStockValue_79EDF234EC1AE38DA851F2A6B13E6F87" xlink:type="locator" />
    <link:presentationArc order="4" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StockholdersEquityAbstract_CAC5E9ABF769262D0C4DF2A6B13D210B" xlink:to="loc_us-gaap_TreasuryStockValue_79EDF234EC1AE38DA851F2A6B13E6F87" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RetainedEarningsAccumulatedDeficit" xlink:label="loc_us-gaap_RetainedEarningsAccumulatedDeficit_A04CDAA64ACC634C3FE6F2A6B13E6CA5" xlink:type="locator" />
    <link:presentationArc order="5" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StockholdersEquityAbstract_CAC5E9ABF769262D0C4DF2A6B13D210B" xlink:to="loc_us-gaap_RetainedEarningsAccumulatedDeficit_A04CDAA64ACC634C3FE6F2A6B13E6CA5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StockholdersEquity" xlink:label="loc_us-gaap_StockholdersEquity_2A1906DB93615DA66A35F2A6B13EEC56" xlink:type="locator" />
    <link:presentationArc order="6" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StockholdersEquityAbstract_CAC5E9ABF769262D0C4DF2A6B13D210B" xlink:to="loc_us-gaap_StockholdersEquity_2A1906DB93615DA66A35F2A6B13EEC56" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LiabilitiesAndStockholdersEquity" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquity_C63FC185CE6A711C4520F2A6B13EEE87" xlink:type="locator" />
    <link:presentationArc order="13" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_C46257078396D13912AEF2A6B13BCD41" xlink:to="loc_us-gaap_LiabilitiesAndStockholdersEquity_C63FC185CE6A711C4520F2A6B13EEE87" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.oesx.com/role/UnauditedCondensedConsolidatedBalanceSheetsParenthetical" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementOfFinancialPositionAbstract" xlink:label="loc_us-gaap_StatementOfFinancialPositionAbstract_382F8074285F56A7B9FF8796817E5A9D" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PreferredStockParOrStatedValuePerShare" xlink:label="loc_us-gaap_PreferredStockParOrStatedValuePerShare_A23EF796B26456A3803C37D573C8917C" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfFinancialPositionAbstract_382F8074285F56A7B9FF8796817E5A9D" xlink:to="loc_us-gaap_PreferredStockParOrStatedValuePerShare_A23EF796B26456A3803C37D573C8917C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PreferredStockSharesAuthorized" xlink:label="loc_us-gaap_PreferredStockSharesAuthorized_FDA40FC1ACBB5AE793D8B1C09264714B" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfFinancialPositionAbstract_382F8074285F56A7B9FF8796817E5A9D" xlink:to="loc_us-gaap_PreferredStockSharesAuthorized_FDA40FC1ACBB5AE793D8B1C09264714B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PreferredStockSharesIssued" xlink:label="loc_us-gaap_PreferredStockSharesIssued_FFFF8851402E529E95308154DE24BE21" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfFinancialPositionAbstract_382F8074285F56A7B9FF8796817E5A9D" xlink:to="loc_us-gaap_PreferredStockSharesIssued_FFFF8851402E529E95308154DE24BE21" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PreferredStockSharesOutstanding" xlink:label="loc_us-gaap_PreferredStockSharesOutstanding_7FE1B8A9AD7C5142814F1105003A501F" xlink:type="locator" />
    <link:presentationArc order="4" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfFinancialPositionAbstract_382F8074285F56A7B9FF8796817E5A9D" xlink:to="loc_us-gaap_PreferredStockSharesOutstanding_7FE1B8A9AD7C5142814F1105003A501F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CommonStockNoParValue" xlink:label="loc_us-gaap_CommonStockNoParValue_BDF95F546B545CFCAD28AB426200420D" xlink:type="locator" />
    <link:presentationArc order="5" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfFinancialPositionAbstract_382F8074285F56A7B9FF8796817E5A9D" xlink:to="loc_us-gaap_CommonStockNoParValue_BDF95F546B545CFCAD28AB426200420D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CommonStockSharesAuthorized" xlink:label="loc_us-gaap_CommonStockSharesAuthorized_AE6854218FB058E2A149E79560D33D88" xlink:type="locator" />
    <link:presentationArc order="6" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfFinancialPositionAbstract_382F8074285F56A7B9FF8796817E5A9D" xlink:to="loc_us-gaap_CommonStockSharesAuthorized_AE6854218FB058E2A149E79560D33D88" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CommonStockSharesIssued" xlink:label="loc_us-gaap_CommonStockSharesIssued_BBF008BEC1455E88A87BB447A7FF2BA5" xlink:type="locator" />
    <link:presentationArc order="7" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfFinancialPositionAbstract_382F8074285F56A7B9FF8796817E5A9D" xlink:to="loc_us-gaap_CommonStockSharesIssued_BBF008BEC1455E88A87BB447A7FF2BA5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SharesOutstanding" xlink:label="loc_us-gaap_SharesOutstanding_8AB2F34990705323A18D27610B3ED74A" xlink:type="locator" />
    <link:presentationArc order="8" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfFinancialPositionAbstract_382F8074285F56A7B9FF8796817E5A9D" xlink:to="loc_us-gaap_SharesOutstanding_8AB2F34990705323A18D27610B3ED74A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_TreasuryStockShares" xlink:label="loc_us-gaap_TreasuryStockShares_0F12DC938D9E597EAC4352E7338F71E2" xlink:type="locator" />
    <link:presentationArc order="9" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfFinancialPositionAbstract_382F8074285F56A7B9FF8796817E5A9D" xlink:to="loc_us-gaap_TreasuryStockShares_0F12DC938D9E597EAC4352E7338F71E2" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.oesx.com/role/UnauditedCondensedConsolidatedStatementsOfCashFlows" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementOfCashFlowsAbstract" xlink:label="loc_us-gaap_StatementOfCashFlowsAbstract_2CF6763657EB37A1CD07F2A6CE5EA05A" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract" xlink:label="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_BD3B4C61CB6F500A0513F2A6CE5E447B" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfCashFlowsAbstract_2CF6763657EB37A1CD07F2A6CE5EA05A" xlink:to="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_BD3B4C61CB6F500A0513F2A6CE5E447B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="loc_us-gaap_NetIncomeLoss_CE6844AA782D95037DEEF2A6CE5ED0D6" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_BD3B4C61CB6F500A0513F2A6CE5E447B" xlink:to="loc_us-gaap_NetIncomeLoss_CE6844AA782D95037DEEF2A6CE5ED0D6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AdjustmentsNoncashItemsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" xlink:label="loc_us-gaap_AdjustmentsNoncashItemsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_1BB6C4EB6E6B7A413124F2A6CE5E0068" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_BD3B4C61CB6F500A0513F2A6CE5E447B" xlink:to="loc_us-gaap_AdjustmentsNoncashItemsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_1BB6C4EB6E6B7A413124F2A6CE5E0068" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_Depreciation" xlink:label="loc_us-gaap_Depreciation_28F34F279F881EF1FEA3F2A6CE5EDDFD" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AdjustmentsNoncashItemsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_1BB6C4EB6E6B7A413124F2A6CE5E0068" xlink:to="loc_us-gaap_Depreciation_28F34F279F881EF1FEA3F2A6CE5EDDFD" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AdjustmentForAmortization" xlink:label="loc_us-gaap_AdjustmentForAmortization_074AED8F863E6ADE39A2F2A6CE5F6315" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AdjustmentsNoncashItemsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_1BB6C4EB6E6B7A413124F2A6CE5E0068" xlink:to="loc_us-gaap_AdjustmentForAmortization_074AED8F863E6ADE39A2F2A6CE5F6315" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareBasedCompensation" xlink:label="loc_us-gaap_ShareBasedCompensation_DC381CA8F8C8A398DFE5F2A6CE5F260D" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AdjustmentsNoncashItemsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_1BB6C4EB6E6B7A413124F2A6CE5E0068" xlink:to="loc_us-gaap_ShareBasedCompensation_DC381CA8F8C8A398DFE5F2A6CE5F260D" xlink:type="arc" />
    <link:loc xlink:href="oesx-20180630.xsd#oesx_ProvisionForInventoryReserves" xlink:label="loc_oesx_ProvisionForInventoryReserves_04CF79BE705F806ABAA5F2A6CE5F1281" xlink:type="locator" />
    <link:presentationArc order="4" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AdjustmentsNoncashItemsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_1BB6C4EB6E6B7A413124F2A6CE5E0068" xlink:to="loc_oesx_ProvisionForInventoryReserves_04CF79BE705F806ABAA5F2A6CE5F1281" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ProvisionForDoubtfulAccounts" xlink:label="loc_us-gaap_ProvisionForDoubtfulAccounts_68642C053C8737CAB17AF2A6CE5F8002" xlink:type="locator" />
    <link:presentationArc order="5" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AdjustmentsNoncashItemsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_1BB6C4EB6E6B7A413124F2A6CE5E0068" xlink:to="loc_us-gaap_ProvisionForDoubtfulAccounts_68642C053C8737CAB17AF2A6CE5F8002" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherNoncashIncomeExpense" xlink:label="loc_us-gaap_OtherNoncashIncomeExpense_DA0E09CEA15ADE25211FF2A6CE5FC4AE" xlink:type="locator" />
    <link:presentationArc order="6" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AdjustmentsNoncashItemsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_1BB6C4EB6E6B7A413124F2A6CE5E0068" xlink:to="loc_us-gaap_OtherNoncashIncomeExpense_DA0E09CEA15ADE25211FF2A6CE5FC4AE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncreaseDecreaseInOperatingCapitalAbstract" xlink:label="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_1E7E23C77C6D618E84D7F2A6CE5F1BEB" xlink:type="locator" />
    <link:presentationArc order="7" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AdjustmentsNoncashItemsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_1BB6C4EB6E6B7A413124F2A6CE5E0068" xlink:to="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_1E7E23C77C6D618E84D7F2A6CE5F1BEB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncreaseDecreaseInAccountsReceivable" xlink:label="loc_us-gaap_IncreaseDecreaseInAccountsReceivable_2B12C33643934FA616D4F2A6CE60DF5D" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_1E7E23C77C6D618E84D7F2A6CE5F1BEB" xlink:to="loc_us-gaap_IncreaseDecreaseInAccountsReceivable_2B12C33643934FA616D4F2A6CE60DF5D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncreaseDecreaseInUnbilledReceivables" xlink:label="loc_us-gaap_IncreaseDecreaseInUnbilledReceivables_7C6A916328EB3FF021B3F2AE393730D4" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_1E7E23C77C6D618E84D7F2A6CE5F1BEB" xlink:to="loc_us-gaap_IncreaseDecreaseInUnbilledReceivables_7C6A916328EB3FF021B3F2AE393730D4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncreaseDecreaseInInventories" xlink:label="loc_us-gaap_IncreaseDecreaseInInventories_D38F43A0BF3C3FB519FCF2A6CE603AAD" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_1E7E23C77C6D618E84D7F2A6CE5F1BEB" xlink:to="loc_us-gaap_IncreaseDecreaseInInventories_D38F43A0BF3C3FB519FCF2A6CE603AAD" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncreaseDecreaseInDeferredCharges" xlink:label="loc_us-gaap_IncreaseDecreaseInDeferredCharges_8893898550E84FC631D9F2A6CE60DB9D" xlink:type="locator" />
    <link:presentationArc order="4" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_1E7E23C77C6D618E84D7F2A6CE5F1BEB" xlink:to="loc_us-gaap_IncreaseDecreaseInDeferredCharges_8893898550E84FC631D9F2A6CE60DB9D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets" xlink:label="loc_us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets_A2EA02CBBBDEB68B9A8EF2A6CE605E00" xlink:type="locator" />
    <link:presentationArc order="5" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_1E7E23C77C6D618E84D7F2A6CE5F1BEB" xlink:to="loc_us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets_A2EA02CBBBDEB68B9A8EF2A6CE605E00" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncreaseDecreaseInAccountsPayable" xlink:label="loc_us-gaap_IncreaseDecreaseInAccountsPayable_227DD4A7E1122CE24760F2A6CE611FDC" xlink:type="locator" />
    <link:presentationArc order="6" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_1E7E23C77C6D618E84D7F2A6CE5F1BEB" xlink:to="loc_us-gaap_IncreaseDecreaseInAccountsPayable_227DD4A7E1122CE24760F2A6CE611FDC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncreaseDecreaseInAccruedLiabilities" xlink:label="loc_us-gaap_IncreaseDecreaseInAccruedLiabilities_FA05A7644A04B6B35B3DF2A6CE616D50" xlink:type="locator" />
    <link:presentationArc order="7" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_1E7E23C77C6D618E84D7F2A6CE5F1BEB" xlink:to="loc_us-gaap_IncreaseDecreaseInAccruedLiabilities_FA05A7644A04B6B35B3DF2A6CE616D50" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncreaseDecreaseInDeferredRevenue" xlink:label="loc_us-gaap_IncreaseDecreaseInDeferredRevenue_CA30B5B8EF827D568974F2A6CE6163FC" xlink:type="locator" />
    <link:presentationArc order="8" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_1E7E23C77C6D618E84D7F2A6CE5F1BEB" xlink:to="loc_us-gaap_IncreaseDecreaseInDeferredRevenue_CA30B5B8EF827D568974F2A6CE6163FC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:label="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_841AC7F9EA8249ED81A7F2A6CE617199" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_BD3B4C61CB6F500A0513F2A6CE5E447B" xlink:to="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_841AC7F9EA8249ED81A7F2A6CE617199" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract" xlink:label="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_EB9775223C66EDFE1424F2A6CE6194F6" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfCashFlowsAbstract_2CF6763657EB37A1CD07F2A6CE5EA05A" xlink:to="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_EB9775223C66EDFE1424F2A6CE6194F6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PaymentsToAcquirePropertyPlantAndEquipment" xlink:label="loc_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_EF7538A059DE21BCDD7CF2A6CE616771" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_EB9775223C66EDFE1424F2A6CE6194F6" xlink:to="loc_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_EF7538A059DE21BCDD7CF2A6CE616771" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PaymentsToAcquireIntangibleAssets" xlink:label="loc_us-gaap_PaymentsToAcquireIntangibleAssets_32DD79B3629DE21CFC0BF2A6CE62865F" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_EB9775223C66EDFE1424F2A6CE6194F6" xlink:to="loc_us-gaap_PaymentsToAcquireIntangibleAssets_32DD79B3629DE21CFC0BF2A6CE62865F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:label="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_2971FF4731D1461854F4F2A6CE6214E9" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_EB9775223C66EDFE1424F2A6CE6194F6" xlink:to="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_2971FF4731D1461854F4F2A6CE6214E9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract" xlink:label="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_D172022ACCC78F35ABB3F2A6CE62617E" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfCashFlowsAbstract_2CF6763657EB37A1CD07F2A6CE5EA05A" xlink:to="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_D172022ACCC78F35ABB3F2A6CE62617E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RepaymentsOfLongTermDebt" xlink:label="loc_us-gaap_RepaymentsOfLongTermDebt_441C772F5182648990D7F2A6CE628A3C" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_D172022ACCC78F35ABB3F2A6CE62617E" xlink:to="loc_us-gaap_RepaymentsOfLongTermDebt_441C772F5182648990D7F2A6CE628A3C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ProceedsFromLongTermLinesOfCredit" xlink:label="loc_us-gaap_ProceedsFromLongTermLinesOfCredit_D91A29C3EEBF3ED32FF7F2A6CE625D2A" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_D172022ACCC78F35ABB3F2A6CE62617E" xlink:to="loc_us-gaap_ProceedsFromLongTermLinesOfCredit_D91A29C3EEBF3ED32FF7F2A6CE625D2A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RepaymentsOfLongTermLinesOfCredit" xlink:label="loc_us-gaap_RepaymentsOfLongTermLinesOfCredit_BFD61EC80A68161FAFF5F2A6CE63E38C" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_D172022ACCC78F35ABB3F2A6CE62617E" xlink:to="loc_us-gaap_RepaymentsOfLongTermLinesOfCredit_BFD61EC80A68161FAFF5F2A6CE63E38C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PaymentsRelatedToTaxWithholdingForShareBasedCompensation" xlink:label="loc_us-gaap_PaymentsRelatedToTaxWithholdingForShareBasedCompensation_373CEEA29A5E7F533F2BF2A6CE63DFA1" xlink:type="locator" />
    <link:presentationArc order="4" preferredLabel="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_D172022ACCC78F35ABB3F2A6CE62617E" xlink:to="loc_us-gaap_PaymentsRelatedToTaxWithholdingForShareBasedCompensation_373CEEA29A5E7F533F2BF2A6CE63DFA1" xlink:type="arc" />
    <link:loc xlink:href="oesx-20180630.xsd#oesx_ProceedsFromExerciseOfWarrantsAndStockOptions" xlink:label="loc_oesx_ProceedsFromExerciseOfWarrantsAndStockOptions_0AC0E3F297E4E46F5B74F2A6CE63C7D8" xlink:type="locator" />
    <link:presentationArc order="5" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_D172022ACCC78F35ABB3F2A6CE62617E" xlink:to="loc_oesx_ProceedsFromExerciseOfWarrantsAndStockOptions_0AC0E3F297E4E46F5B74F2A6CE63C7D8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:label="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_7D88D92BC3F51CEED6C7F2A6CE63F685" xlink:type="locator" />
    <link:presentationArc order="6" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_D172022ACCC78F35ABB3F2A6CE62617E" xlink:to="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_7D88D92BC3F51CEED6C7F2A6CE63F685" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease" xlink:label="loc_us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease_1DEC4E6FA80012E99BE0F2A6CE631176" xlink:type="locator" />
    <link:presentationArc order="4" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfCashFlowsAbstract_2CF6763657EB37A1CD07F2A6CE5EA05A" xlink:to="loc_us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease_1DEC4E6FA80012E99BE0F2A6CE631176" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:label="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_50B71073C51B19EA09D6F2A6CE638081" xlink:type="locator" />
    <link:presentationArc order="5" preferredLabel="http://www.xbrl.org/2003/role/periodStartLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfCashFlowsAbstract_2CF6763657EB37A1CD07F2A6CE5EA05A" xlink:to="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_50B71073C51B19EA09D6F2A6CE638081" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:label="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_72F56AE68BBAAB7D3DBFF2A6CE649D4B" xlink:type="locator" />
    <link:presentationArc order="6" preferredLabel="http://www.xbrl.org/2003/role/periodEndLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfCashFlowsAbstract_2CF6763657EB37A1CD07F2A6CE5EA05A" xlink:to="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_72F56AE68BBAAB7D3DBFF2A6CE649D4B" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.oesx.com/role/UnauditedCondensedConsolidatedStatementsOfOperations" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncomeStatementAbstract" xlink:label="loc_us-gaap_IncomeStatementAbstract_A01156451108F17F99D91173789EB922" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaap_StatementTable_7CBFD92E43286EA9E4151173789E4045" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncomeStatementAbstract_A01156451108F17F99D91173789EB922" xlink:to="loc_us-gaap_StatementTable_7CBFD92E43286EA9E4151173789E4045" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ProductOrServiceAxis" xlink:label="loc_us-gaap_ProductOrServiceAxis_0CFFD565552191AD2AFB1173789F50C2" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementTable_7CBFD92E43286EA9E4151173789E4045" xlink:to="loc_us-gaap_ProductOrServiceAxis_0CFFD565552191AD2AFB1173789F50C2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ProductsAndServicesDomain" xlink:label="loc_us-gaap_ProductsAndServicesDomain_E170F8706D347126C6E51173789F0957" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ProductOrServiceAxis_0CFFD565552191AD2AFB1173789F50C2" xlink:to="loc_us-gaap_ProductsAndServicesDomain_E170F8706D347126C6E51173789F0957" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ProductMember" xlink:label="loc_us-gaap_ProductMember_EF7CFD039439C5DC9C5E1173789F786D" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ProductsAndServicesDomain_E170F8706D347126C6E51173789F0957" xlink:to="loc_us-gaap_ProductMember_EF7CFD039439C5DC9C5E1173789F786D" xlink:type="arc" />
    <link:loc xlink:href="oesx-20180630.xsd#oesx_ServiceMember" xlink:label="loc_oesx_ServiceMember_374845C7792CBDA823731173789F9D5E" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ProductsAndServicesDomain_E170F8706D347126C6E51173789F0957" xlink:to="loc_oesx_ServiceMember_374845C7792CBDA823731173789F9D5E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaap_StatementLineItems_72EE0A8C147B68B2B1731173789F705A" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementTable_7CBFD92E43286EA9E4151173789E4045" xlink:to="loc_us-gaap_StatementLineItems_72EE0A8C147B68B2B1731173789F705A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_Revenues" xlink:label="loc_us-gaap_Revenues_9E87EC9D3B17F07E2754119B4956D1E9" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementLineItems_72EE0A8C147B68B2B1731173789F705A" xlink:to="loc_us-gaap_Revenues_9E87EC9D3B17F07E2754119B4956D1E9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CostOfGoodsAndServicesSold" xlink:label="loc_us-gaap_CostOfGoodsAndServicesSold_6421E9AB679A460AAB31117378A0F3E2" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementLineItems_72EE0A8C147B68B2B1731173789F705A" xlink:to="loc_us-gaap_CostOfGoodsAndServicesSold_6421E9AB679A460AAB31117378A0F3E2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_GrossProfit" xlink:label="loc_us-gaap_GrossProfit_3D5363C83AEA7A72C5FE117378A02B96" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementLineItems_72EE0A8C147B68B2B1731173789F705A" xlink:to="loc_us-gaap_GrossProfit_3D5363C83AEA7A72C5FE117378A02B96" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OperatingExpensesAbstract" xlink:label="loc_us-gaap_OperatingExpensesAbstract_E59BB66EBC74DF42CA29117378A1EFB6" xlink:type="locator" />
    <link:presentationArc order="4" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementLineItems_72EE0A8C147B68B2B1731173789F705A" xlink:to="loc_us-gaap_OperatingExpensesAbstract_E59BB66EBC74DF42CA29117378A1EFB6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_GeneralAndAdministrativeExpense" xlink:label="loc_us-gaap_GeneralAndAdministrativeExpense_BDABFB3E91DCE6E947DC117378A11F43" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_OperatingExpensesAbstract_E59BB66EBC74DF42CA29117378A1EFB6" xlink:to="loc_us-gaap_GeneralAndAdministrativeExpense_BDABFB3E91DCE6E947DC117378A11F43" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SellingAndMarketingExpense" xlink:label="loc_us-gaap_SellingAndMarketingExpense_D60F820E38B05BDAC736117378A1FBE6" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_OperatingExpensesAbstract_E59BB66EBC74DF42CA29117378A1EFB6" xlink:to="loc_us-gaap_SellingAndMarketingExpense_D60F820E38B05BDAC736117378A1FBE6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ResearchAndDevelopmentExpense" xlink:label="loc_us-gaap_ResearchAndDevelopmentExpense_31625382DD9F6509B31C117378A15B03" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_OperatingExpensesAbstract_E59BB66EBC74DF42CA29117378A1EFB6" xlink:to="loc_us-gaap_ResearchAndDevelopmentExpense_31625382DD9F6509B31C117378A15B03" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OperatingExpenses" xlink:label="loc_us-gaap_OperatingExpenses_FCB0589584716E274E36117378A198FB" xlink:type="locator" />
    <link:presentationArc order="4" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_OperatingExpensesAbstract_E59BB66EBC74DF42CA29117378A1EFB6" xlink:to="loc_us-gaap_OperatingExpenses_FCB0589584716E274E36117378A198FB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OperatingIncomeLoss" xlink:label="loc_us-gaap_OperatingIncomeLoss_D844FC5793BCB441C16A117378A2E071" xlink:type="locator" />
    <link:presentationArc order="5" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementLineItems_72EE0A8C147B68B2B1731173789F705A" xlink:to="loc_us-gaap_OperatingIncomeLoss_D844FC5793BCB441C16A117378A2E071" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NonoperatingIncomeExpenseAbstract" xlink:label="loc_us-gaap_NonoperatingIncomeExpenseAbstract_0BA8A3346239B33C538A117378A2F3A4" xlink:type="locator" />
    <link:presentationArc order="6" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementLineItems_72EE0A8C147B68B2B1731173789F705A" xlink:to="loc_us-gaap_NonoperatingIncomeExpenseAbstract_0BA8A3346239B33C538A117378A2F3A4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherNonoperatingIncome" xlink:label="loc_us-gaap_OtherNonoperatingIncome_1271EC7371DF7CCB2D58117378A24B36" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_NonoperatingIncomeExpenseAbstract_0BA8A3346239B33C538A117378A2F3A4" xlink:to="loc_us-gaap_OtherNonoperatingIncome_1271EC7371DF7CCB2D58117378A24B36" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_InterestExpense" xlink:label="loc_us-gaap_InterestExpense_E3441E07393F0EAD8F22117378A24D98" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_NonoperatingIncomeExpenseAbstract_0BA8A3346239B33C538A117378A2F3A4" xlink:to="loc_us-gaap_InterestExpense_E3441E07393F0EAD8F22117378A24D98" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_InvestmentIncomeInterest" xlink:label="loc_us-gaap_InvestmentIncomeInterest_0278B9629B2B11C887D3117378A269B8" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_NonoperatingIncomeExpenseAbstract_0BA8A3346239B33C538A117378A2F3A4" xlink:to="loc_us-gaap_InvestmentIncomeInterest_0278B9629B2B11C887D3117378A269B8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NonoperatingIncomeExpense" xlink:label="loc_us-gaap_NonoperatingIncomeExpense_31F0EF148C20E72DC99D117378A869FB" xlink:type="locator" />
    <link:presentationArc order="4" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_NonoperatingIncomeExpenseAbstract_0BA8A3346239B33C538A117378A2F3A4" xlink:to="loc_us-gaap_NonoperatingIncomeExpense_31F0EF148C20E72DC99D117378A869FB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments_16B70B4B3CF241C48CBA117378A8933E" xlink:type="locator" />
    <link:presentationArc order="7" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementLineItems_72EE0A8C147B68B2B1731173789F705A" xlink:to="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments_16B70B4B3CF241C48CBA117378A8933E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncomeTaxExpenseBenefit" xlink:label="loc_us-gaap_IncomeTaxExpenseBenefit_29A899CD0A0E3FD37270117378A86FE7" xlink:type="locator" />
    <link:presentationArc order="8" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementLineItems_72EE0A8C147B68B2B1731173789F705A" xlink:to="loc_us-gaap_IncomeTaxExpenseBenefit_29A899CD0A0E3FD37270117378A86FE7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="loc_us-gaap_NetIncomeLoss_57221248A8B3A751DA66117378A84D83" xlink:type="locator" />
    <link:presentationArc order="9" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementLineItems_72EE0A8C147B68B2B1731173789F705A" xlink:to="loc_us-gaap_NetIncomeLoss_57221248A8B3A751DA66117378A84D83" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EarningsPerShareBasic" xlink:label="loc_us-gaap_EarningsPerShareBasic_A3C91946C9BA14A43AAE117378A8B38E" xlink:type="locator" />
    <link:presentationArc order="10" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementLineItems_72EE0A8C147B68B2B1731173789F705A" xlink:to="loc_us-gaap_EarningsPerShareBasic_A3C91946C9BA14A43AAE117378A8B38E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_WeightedAverageNumberOfSharesOutstandingBasic" xlink:label="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_199830CF268E30D2A34B117378A937C5" xlink:type="locator" />
    <link:presentationArc order="11" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementLineItems_72EE0A8C147B68B2B1731173789F705A" xlink:to="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_199830CF268E30D2A34B117378A937C5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EarningsPerShareDiluted" xlink:label="loc_us-gaap_EarningsPerShareDiluted_295617A705913319AE5A117378A9A368" xlink:type="locator" />
    <link:presentationArc order="12" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementLineItems_72EE0A8C147B68B2B1731173789F705A" xlink:to="loc_us-gaap_EarningsPerShareDiluted_295617A705913319AE5A117378A9A368" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding" xlink:label="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_032DDCA9D3BEE2696E88117378A96615" xlink:type="locator" />
    <link:presentationArc order="13" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementLineItems_72EE0A8C147B68B2B1731173789F705A" xlink:to="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_032DDCA9D3BEE2696E88117378A96615" xlink:type="arc" />
  </link:presentationLink>
</link:linkbase>





