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  <xs:element id="ngs_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfRemainingSharesAuthorized" abstract="false" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfRemainingSharesAuthorized" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:sharesItemType"/>
  <xs:element id="ngs_EmployeeServiceShareBasedCompensationNonvestedAwardsVestedInPeriodStockOptionsWeightedAverageGrantDateFairValue" abstract="false" name="EmployeeServiceShareBasedCompensationNonvestedAwardsVestedInPeriodStockOptionsWeightedAverageGrantDateFairValue" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="num:perShareItemType"/>
  <xs:element id="ngs_LineOfCreditFacilityDefaultTriggerRenderingOfCertainJudgmentsAmount" abstract="false" name="LineOfCreditFacilityDefaultTriggerRenderingOfCertainJudgmentsAmount" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="ngs_CashEquivalentsQualificationMaximumOriginalMaturityOfShortTermInvestments" abstract="false" name="CashEquivalentsQualificationMaximumOriginalMaturityOfShortTermInvestments" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
  <xs:element id="ngs_EquityIncentivePlanMember" abstract="true" name="EquityIncentivePlanMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType"/>
  <xs:element id="ngs_OneCustomerMember" abstract="true" name="OneCustomerMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType"/>
  <xs:element id="ngs_GenisHoldingsLLCMember" abstract="true" name="GenisHoldingsLLCMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType"/>
  <xs:element id="ngs_RentalContractsExcludingLargeHorsepowerCompressorsMember" abstract="true" name="RentalContractsExcludingLargeHorsepowerCompressorsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType"/>
  <xs:element id="ngs_SalesRevenueGoodsNetAndRentalIncomeMember" abstract="true" name="SalesRevenueGoodsNetAndRentalIncomeMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType"/>
  <xs:element id="ngs_RentalCompressorUnitWorkInProgressMember" abstract="true" name="RentalCompressorUnitWorkInProgressMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType"/>
  <xs:element id="ngs_ProductSalesMember" abstract="true" name="ProductSalesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType"/>
  <xs:element id="ngs_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsCancelledOrForfeitedInPeriodIntrinsicValue" abstract="false" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsCancelledOrForfeitedInPeriodIntrinsicValue" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="ngs_IntangibleAssetsTable" abstract="true" name="IntangibleAssetsTable" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrldt:hypercubeItem" type="xbrli:stringItemType"/>
  <xs:element id="ngs_LineOfCreditFacilityCurrentBorrowingCapacityComponentPercentageOfEligibleEquipmentInventory" abstract="false" name="LineOfCreditFacilityCurrentBorrowingCapacityComponentPercentageOfEligibleEquipmentInventory" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="num:percentItemType"/>
  <xs:element id="ngs_RentalContractsLargeHorsepowerCompressorsMember" abstract="true" name="RentalContractsLargeHorsepowerCompressorsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType"/>
  <xs:element id="ngs_RangeThreeMember" abstract="true" name="RangeThreeMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType"/>
  <xs:element id="ngs_IntangibleAssetsAccumulatedAmortization" abstract="false" name="IntangibleAssetsAccumulatedAmortization" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="ngs_NGLLCMember" abstract="true" name="NGLLCMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType"/>
  <xs:element id="ngs_WeightedAverageSharesOutstandingBasicAndDilutedAbstract" abstract="true" name="WeightedAverageSharesOutstandingBasicAndDilutedAbstract" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="ngs_DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsDeferredCompensation" abstract="false" name="DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsDeferredCompensation" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="ngs_RentalEquipmentNet" abstract="false" name="RentalEquipmentNet" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="ngs_EmployeeServiceShareBasedCompensationNonvestedAwardsOutstandingNumberStockOptions" abstract="false" name="EmployeeServiceShareBasedCompensationNonvestedAwardsOutstandingNumberStockOptions" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:sharesItemType"/>
</xs:schema>
