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  <xsd:element abstract="true" id="oesx_CustomerOneMember" name="CustomerOneMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="oesx_CustomerTwoMember" name="CustomerTwoMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="oesx_DeLageLandenFinancialServicesInc.Member" name="DeLageLandenFinancialServicesInc.Member" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="oesx_DebtInstrumentBuyoutOption" name="DebtInstrumentBuyoutOption" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="oesx_DebtInstrumentNumberOfContractsForCollateral" name="DebtInstrumentNumberOfContractsForCollateral" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="instant" />
  <xsd:element abstract="true" id="oesx_DebtTextualAbstract" name="DebtTextualAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="oesx_December2014OTAFinanceProgramMember" name="December2014OTAFinanceProgramMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="oesx_DeferredCompensationArrangementWithIndividualDiscretionaryBonusPaymentPercentage" name="DeferredCompensationArrangementWithIndividualDiscretionaryBonusPaymentPercentage" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="oesx_DeferredCompensationArrangementwithIndividualCashAwardThresholdProfitBeforeTaxes" name="DeferredCompensationArrangementwithIndividualCashAwardThresholdProfitBeforeTaxes" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element id="oesx_DeferredCompensationArrangementwithIndividualCashAwardThresholdRevenueGrowthPercent" name="DeferredCompensationArrangementwithIndividualCashAwardThresholdRevenueGrowthPercent" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="oesx_DeferredFinancingCostsAmortizedOverUsefulLifeOfDebtIssueMaximum" name="DeferredFinancingCostsAmortizedOverUsefulLifeOfDebtIssueMaximum" nillable="true" substitutionGroup="xbrli:item" type="xbrli:durationItemType" xbrli:periodType="duration" />
  <xsd:element id="oesx_DeferredFinancingCostsAmortizedOverUsefulLifeOfDebtIssueMinimum" name="DeferredFinancingCostsAmortizedOverUsefulLifeOfDebtIssueMinimum" nillable="true" substitutionGroup="xbrli:item" type="xbrli:durationItemType" xbrli:periodType="duration" />
  <xsd:element id="oesx_DeferredTaxAssetDeferredIncomeCurrent" name="DeferredTaxAssetDeferredIncomeCurrent" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="oesx_DeferredTaxAssetDeferredIncomeNoncurrent" name="DeferredTaxAssetDeferredIncomeNoncurrent" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="oesx_DeferredTaxAssetsInventoryAccrualsAndReservesCurrent" name="DeferredTaxAssetsInventoryAccrualsAndReservesCurrent" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="oesx_DeferredTaxAssetsInventoryAccrualsAndReservesNoncurrent" name="DeferredTaxAssetsInventoryAccrualsAndReservesNoncurrent" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="oesx_DeferredTaxAssetsOtherCurrent" name="DeferredTaxAssetsOtherCurrent" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element abstract="true" id="oesx_DistributionServicesMember" name="DistributionServicesMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="oesx_DocumentAndEntityInformationAbstract" name="DocumentAndEntityInformationAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element id="oesx_EffectiveIncomeTaxRateReconciliationSharebasedCompensationExcessTaxBenefitPercent" name="EffectiveIncomeTaxRateReconciliationSharebasedCompensationExcessTaxBenefitPercent" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="oesx_EffectiveIncomeTaxRateReconciliationTaxCutsAndJobsActOf2017Percent" name="EffectiveIncomeTaxRateReconciliationTaxCutsAndJobsActOf2017Percent" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="oesx_EmployeeServiceShareBasedCompensationNonvestedAwardsCompensationCostNotYetRecognizedDueInFiveYears" name="EmployeeServiceShareBasedCompensationNonvestedAwardsCompensationCostNotYetRecognizedDueInFiveYears" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="oesx_EmployeeServiceShareBasedCompensationNonvestedAwardsCompensationCostNotYetRecognizedDueInFourYears" name="EmployeeServiceShareBasedCompensationNonvestedAwardsCompensationCostNotYetRecognizedDueInFourYears" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="oesx_EmployeeServiceShareBasedCompensationNonvestedAwardsCompensationCostNotYetRecognizedDueInThreeYears" name="EmployeeServiceShareBasedCompensationNonvestedAwardsCompensationCostNotYetRecognizedDueInThreeYears" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="oesx_EmployeeServiceShareBasedCompensationNonvestedAwardsCompensationCostNotYetRecognizedDueInTwoYears" name="EmployeeServiceShareBasedCompensationNonvestedAwardsCompensationCostNotYetRecognizedDueInTwoYears" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="oesx_EmployeeServiceShareBasedCompensationNonvestedAwardsCompensationCostNotYetRecognizedDueThereafter" name="EmployeeServiceShareBasedCompensationNonvestedAwardsCompensationCostNotYetRecognizedDueThereafter" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="oesx_EmployeeServiceShareBasedCompensationNonvestedAwardsCompensationCostNotYetRecognizedNextTwelveMonths" name="EmployeeServiceShareBasedCompensationNonvestedAwardsCompensationCostNotYetRecognizedNextTwelveMonths" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="oesx_EmployeeStockPurchasePlanClosingMarketPriceOfSharesPurchased" name="EmployeeStockPurchasePlanClosingMarketPriceOfSharesPurchased" nillable="true" substitutionGroup="xbrli:item" type="num:perShareItemType" xbrli:periodType="duration" />
  <xsd:element id="oesx_EmployeeStockPurchasePlanPurchasePriceToMarketPriceMatchingPercentage" name="EmployeeStockPurchasePlanPurchasePriceToMarketPriceMatchingPercentage" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="instant" />
  <xsd:element id="oesx_EmployeeStockPurchasePlansDebtStructureDirectLoanAmount" name="EmployeeStockPurchasePlansDebtStructureDirectLoanAmount" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element id="oesx_EmployeeStockPurchasePlansDebtStructureDirectLoanRepaymentAmount" name="EmployeeStockPurchasePlansDebtStructureDirectLoanRepaymentAmount" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element id="oesx_EmployeeStockPurchasePlansDebtStructureSharesIssued" name="EmployeeStockPurchasePlansDebtStructureSharesIssued" nillable="true" substitutionGroup="xbrli:item" type="xbrli:sharesItemType" xbrli:periodType="duration" />
  <xsd:element id="oesx_EmployeeStockPurchasePlansSharesAuthorized" name="EmployeeStockPurchasePlansSharesAuthorized" nillable="true" substitutionGroup="xbrli:item" type="xbrli:sharesItemType" xbrli:periodType="instant" />
  <xsd:element abstract="true" id="oesx_EngineeredSystemsMember" name="EngineeredSystemsMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="oesx_EntityThatCurrentDirectorOwnsMinorityInterestAndServesAsBoardOfDirectorsChairmanMember" name="EntityThatCurrentDirectorOwnsMinorityInterestAndServesAsBoardOfDirectorsChairmanMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="oesx_FairValueOfClosingCommonStockPrice" name="FairValueOfClosingCommonStockPrice" nillable="true" substitutionGroup="xbrli:item" type="num:perShareItemType" xbrli:periodType="instant" />
  <xsd:element id="oesx_FiniteLivedAndIndefiniteLivedIntangibleAssetsGross" name="FiniteLivedAndIndefiniteLivedIntangibleAssetsGross" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="oesx_GoodwillImpairmentLossAndImpairmentOfRealEstate" name="GoodwillImpairmentLossAndImpairmentOfRealEstate" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element id="oesx_InventoryFinishedGoodsValuationReserves" name="InventoryFinishedGoodsValuationReserves" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="oesx_InventoryRawMaterialsAndSuppliesValuationReserves" name="InventoryRawMaterialsAndSuppliesValuationReserves" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="oesx_InventoryReserveAndOtherAdjustments" name="InventoryReserveAndOtherAdjustments" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element id="oesx_InventoryReserveLengthofTimeofInventoryUsageConsidered" name="InventoryReserveLengthofTimeofInventoryUsageConsidered" nillable="true" substitutionGroup="xbrli:item" type="xbrli:durationItemType" xbrli:periodType="duration" />
  <xsd:element id="oesx_InventoryWorkInProcessValuationReserves" name="InventoryWorkInProcessValuationReserves" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="oesx_LessorLeasingArrangementsOperatingLeasesNumberOfExtensionOptions" name="LessorLeasingArrangementsOperatingLeasesNumberOfExtensionOptions" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="duration" />
  <xsd:element id="oesx_LimitedProductWarrantyTerm" name="LimitedProductWarrantyTerm" nillable="true" substitutionGroup="xbrli:item" type="xbrli:durationItemType" xbrli:periodType="duration" />
  <xsd:element id="oesx_LineOfCreditFacilityAdditionalBorrowingCapacity" name="LineOfCreditFacilityAdditionalBorrowingCapacity" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="oesx_LineOfCreditFacilityCovenantTermsMinimumIndebtednessRatio" name="LineOfCreditFacilityCovenantTermsMinimumIndebtednessRatio" nillable="true" substitutionGroup="xbrli:item" type="xbrli:pureItemType" xbrli:periodType="instant" />
  <xsd:element id="oesx_LineOfCreditFacilityPotentialMaximumBorrowingCapacity" name="LineOfCreditFacilityPotentialMaximumBorrowingCapacity" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element abstract="true" id="oesx_ManitowocManufacturingAndDistributionFacilityMember" name="ManitowocManufacturingAndDistributionFacilityMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="oesx_MaximumAmountLimitForEmployeeStockPurchasePlanPerEmployee" name="MaximumAmountLimitForEmployeeStockPurchasePlanPerEmployee" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="oesx_MinimumSubscriptionPercentage" name="MinimumSubscriptionPercentage" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="oesx_NonEmployeeDirectorMember" name="NonEmployeeDirectorMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="oesx_NumberOfFinancialInstitutions" name="NumberOfFinancialInstitutions" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="duration" />
  <xsd:element id="oesx_NumberOfRecentlyRetiredMembersOfTheBoard" name="NumberOfRecentlyRetiredMembersOfTheBoard" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="oesx_October2011Member" name="October2011Member" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="oesx_OperatingLeasesAnnualRentExpense" name="OperatingLeasesAnnualRentExpense" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="oesx_OperatingLeasesMonthlyRentalPaymentsReceivable" name="OperatingLeasesMonthlyRentalPaymentsReceivable" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="oesx_OtherLongTermDebtMember" name="OtherLongTermDebtMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="oesx_PaymentsToAcquirePropertyPlantAndEquipmentAndProductiveAssets" name="PaymentsToAcquirePropertyPlantAndEquipmentAndProductiveAssets" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element id="oesx_PeriodOfTimeStateIncomeTaxReturnsSubjectToExamination" name="PeriodOfTimeStateIncomeTaxReturnsSubjectToExamination" nillable="true" substitutionGroup="xbrli:item" type="xbrli:durationItemType" xbrli:periodType="duration" />
  <xsd:element id="oesx_PeriodOfTimeWithoutInterestAccruingOrPrincipalPaymentsDue" name="PeriodOfTimeWithoutInterestAccruingOrPrincipalPaymentsDue" nillable="true" substitutionGroup="xbrli:item" type="xbrli:durationItemType" xbrli:periodType="duration" />
  <xsd:element id="oesx_ProceedsFromExerciseOfWarrantsAndStockOptions" name="ProceedsFromExerciseOfWarrantsAndStockOptions" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="oesx_RangeEightMember" name="RangeEightMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="oesx_RangeFiveMember" name="RangeFiveMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="oesx_RangeFourMember" name="RangeFourMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="oesx_RangeSixMember" name="RangeSixMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="oesx_RangeThreeMember" name="RangeThreeMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="oesx_RangeTwoMember" name="RangeTwoMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="oesx_RightIssueSharePrice" name="RightIssueSharePrice" nillable="true" substitutionGroup="xbrli:item" type="num:perShareItemType" xbrli:periodType="instant" />
  <xsd:element id="oesx_RightsDistributionDateTriggerNumberOfBusinessDaysAfterCommencementOrOfferOfAcquisition" name="RightsDistributionDateTriggerNumberOfBusinessDaysAfterCommencementOrOfferOfAcquisition" nillable="true" substitutionGroup="xbrli:item" type="xbrli:durationItemType" xbrli:periodType="duration" />
  <xsd:element id="oesx_SaleLeasebackTransactionAreaOfLeasedProperty" name="SaleLeasebackTransactionAreaOfLeasedProperty" nillable="true" substitutionGroup="xbrli:item" type="num:areaItemType" xbrli:periodType="duration" />
  <xsd:element id="oesx_SaleLeasebackTransactionLeaseTerm" name="SaleLeasebackTransactionLeaseTerm" nillable="true" substitutionGroup="xbrli:item" type="xbrli:durationItemType" xbrli:periodType="duration" />
  <xsd:element id="oesx_SaleLeasebackTransactionRentExpensePerSquareFoot" name="SaleLeasebackTransactionRentExpensePerSquareFoot" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="oesx_ServicesPurchasedFromAnImmediateFamilyMemberOfAnExecutiveOfficerMember" name="ServicesPurchasedFromAnImmediateFamilyMemberOfAnExecutiveOfficerMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="oesx_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrantForfeited" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrantForfeited" nillable="true" substitutionGroup="xbrli:item" type="xbrli:sharesItemType" xbrli:periodType="duration" />
  <xsd:element id="oesx_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrantRestrictedShares" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrantRestrictedShares" nillable="true" substitutionGroup="xbrli:item" type="xbrli:sharesItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="oesx_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrantRollForward" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrantRollForward" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element id="oesx_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrantSharesCanceled" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrantSharesCanceled" nillable="true" substitutionGroup="xbrli:item" type="xbrli:sharesItemType" xbrli:periodType="duration" />
  <xsd:element id="oesx_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrantSharesIssuedToEmployee" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrantSharesIssuedToEmployee" nillable="true" substitutionGroup="xbrli:item" type="xbrli:sharesItemType" xbrli:periodType="duration" />
  <xsd:element id="oesx_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrantSharesIssuedToNonEmployee" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrantSharesIssuedToNonEmployee" nillable="true" substitutionGroup="xbrli:item" type="xbrli:sharesItemType" xbrli:periodType="duration" />
  <xsd:element id="oesx_ShareBasedCompensationArrangementByShareBasedPaymentAwardPerSharePrice" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardPerSharePrice" nillable="true" substitutionGroup="xbrli:item" type="num:perShareItemType" xbrli:periodType="duration" />
  <xsd:element id="oesx_SharePurchaseRightsRedemptionPrice" name="SharePurchaseRightsRedemptionPrice" nillable="true" substitutionGroup="xbrli:item" type="num:perShareItemType" xbrli:periodType="instant" />
  <xsd:element id="oesx_SharebasedGoodsandNonemployeeServicesTransactionSecuritiesIssuedValuationPricePerShare" name="SharebasedGoodsandNonemployeeServicesTransactionSecuritiesIssuedValuationPricePerShare" nillable="true" substitutionGroup="xbrli:item" type="num:perShareItemType" xbrli:periodType="duration" />
  <xsd:element id="oesx_StockIssuedDuringPeriodValueStockOptionsandWarrantsExercised" name="StockIssuedDuringPeriodValueStockOptionsandWarrantsExercised" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element id="oesx_StockholdersEquityReceivablefromShareholdersorAffiliatesforIssuanceofCapitalStock" name="StockholdersEquityReceivablefromShareholdersorAffiliatesforIssuanceofCapitalStock" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element id="oesx_StockholdersEquityReceivablefromShareholdersorAffiliatesforIssuanceofCapitalStockShares" name="StockholdersEquityReceivablefromShareholdersorAffiliatesforIssuanceofCapitalStockShares" nillable="true" substitutionGroup="xbrli:item" type="xbrli:sharesItemType" xbrli:periodType="duration" />
  <xsd:element id="oesx_Stockissuedduringperiodsharesstockoptionsandwarrantsexercised" name="Stockissuedduringperiodsharesstockoptionsandwarrantsexercised" nillable="true" substitutionGroup="xbrli:item" type="xbrli:sharesItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="oesx_SummaryOfIssuanceOfStockUnderEmployeeStockOwnershipPlanAbstract" name="SummaryOfIssuanceOfStockUnderEmployeeStockOwnershipPlanAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element id="oesx_TaxCutsandJobsActof2017IncompleteAccountingChangeinTaxRateDeferredTaxAssetProvisionalIncomeTaxExpenseBenefit" name="TaxCutsandJobsActof2017IncompleteAccountingChangeinTaxRateDeferredTaxAssetProvisionalIncomeTaxExpenseBenefit" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="oesx_TwoThousandFourStockAndIncentiveAndAwardPlanMember" name="TwoThousandFourStockAndIncentiveAndAwardPlanMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="oesx_U.S.MarketsMember" name="U.S.MarketsMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="oesx_WellsFargoBankNationalAssociationMember" name="WellsFargoBankNationalAssociationMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="oesx_WisconsinDepartmentOfRevenueMember" name="WisconsinDepartmentOfRevenueMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
</xsd:schema>





