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      <link:roleType roleURI="http://meec.com/role/StockBasedCompensationDetails" id="StockBasedCompensationDetails">
        <link:definition>995495 - Disclosure - Stock Based Compensation (Details)</link:definition>
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        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
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      <link:roleType roleURI="http://meec.com/role/StockBasedCompensationDetailsNarrative" id="StockBasedCompensationDetailsNarrative">
        <link:definition>995496 - Disclosure - Stock Based Compensation (Details Narrative)</link:definition>
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        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
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      <link:roleType roleURI="http://meec.com/role/WarrantsDetailsNarrative" id="WarrantsDetailsNarrative">
        <link:definition>995497 - Disclosure - Warrants (Details Narrative)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
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      <link:roleType roleURI="http://meec.com/role/SegmentAndGeographicInformationDetails" id="SegmentAndGeographicInformationDetails">
        <link:definition>995498 - Disclosure - Segment and Geographic Information (Details)</link:definition>
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        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
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      <link:roleType roleURI="http://meec.com/role/SubsequentEventsDetailsNarrative" id="SubsequentEventsDetailsNarrative">
        <link:definition>995499 - Disclosure - Subsequent Events (Details Narrative)</link:definition>
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        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
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      <link:linkbaseRef xlink:type="simple" xlink:href="meec-20260630_lab.xml" xlink:role="http://www.xbrl.org/2003/role/labelLinkbaseRef" xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" />
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      <link:linkbaseRef xlink:type="simple" xlink:href="meec-20260630_def.xml" xlink:role="http://www.xbrl.org/2003/role/definitionLinkbaseRef" xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" />
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  <element name="LicenseRevenueMember" id="meec_LicenseRevenueMember" nillable="true" xbrli:periodType="duration" type="nonnum:domainItemType" substitutionGroup="xbrli:item" />
  <element name="EquipmentRevenueMember" id="meec_EquipmentRevenueMember" nillable="true" xbrli:periodType="duration" type="nonnum:domainItemType" substitutionGroup="xbrli:item" />
  <element name="LabEquipmentMember" id="meec_LabEquipmentMember" nillable="true" xbrli:periodType="duration" type="nonnum:domainItemType" substitutionGroup="xbrli:item" />
  <element name="CommonSharesMember" id="meec_CommonSharesMember" nillable="true" xbrli:periodType="duration" type="nonnum:domainItemType" substitutionGroup="xbrli:item" />
  <element name="EquipmentAndInstallationMember" id="meec_EquipmentAndInstallationMember" nillable="true" xbrli:periodType="duration" type="nonnum:domainItemType" substitutionGroup="xbrli:item" />
  <element name="FirstCustomerMember" id="meec_FirstCustomerMember" nillable="true" xbrli:periodType="duration" type="nonnum:domainItemType" substitutionGroup="xbrli:item" />
  <element name="SecondCustomerMember" id="meec_SecondCustomerMember" nillable="true" xbrli:periodType="duration" type="nonnum:domainItemType" substitutionGroup="xbrli:item" />
  <element name="ThirdCustomerMember" id="meec_ThirdCustomerMember" nillable="true" xbrli:periodType="duration" type="nonnum:domainItemType" substitutionGroup="xbrli:item" />
  <element name="TwoVendorsMember" id="meec_TwoVendorsMember" nillable="true" xbrli:periodType="duration" type="nonnum:domainItemType" substitutionGroup="xbrli:item" />
  <element name="TruckingEquipmentMember" id="meec_TruckingEquipmentMember" nillable="true" xbrli:periodType="duration" type="nonnum:domainItemType" substitutionGroup="xbrli:item" />
  <element name="TwoThousandSeventeenPlanMember" id="meec_TwoThousandSeventeenPlanMember" nillable="true" xbrli:periodType="duration" type="nonnum:domainItemType" substitutionGroup="xbrli:item" />
  <element name="ProfitShareMember" id="meec_ProfitShareMember" nillable="true" xbrli:periodType="duration" type="nonnum:domainItemType" substitutionGroup="xbrli:item" />
  <element name="OfficeEquipmentComputerEquipmentAndSoftwaretMember" id="meec_OfficeEquipmentComputerEquipmentAndSoftwaretMember" nillable="true" xbrli:periodType="duration" type="nonnum:domainItemType" substitutionGroup="xbrli:item" />
  <element name="KayeCooperKayRosenbergLLPMember" id="meec_KayeCooperKayRosenbergLLPMember" nillable="true" xbrli:periodType="duration" type="nonnum:domainItemType" substitutionGroup="xbrli:item" />
  <element name="CorsicanaWarehouseMember" id="meec_CorsicanaWarehouseMember" nillable="true" xbrli:periodType="duration" type="nonnum:domainItemType" substitutionGroup="xbrli:item" />
  <element name="JulyOneTwoZeroOneFiveMember" id="meec_JulyOneTwoZeroOneFiveMember" nillable="true" xbrli:periodType="duration" type="nonnum:domainItemType" substitutionGroup="xbrli:item" />
  <element name="CommercialCustomersMember" id="meec_CommercialCustomersMember" nillable="true" xbrli:periodType="duration" type="nonnum:domainItemType" substitutionGroup="xbrli:item" />
  <element name="BoardOfDirectorsMember" id="meec_BoardOfDirectorsMember" nillable="true" xbrli:periodType="duration" type="nonnum:domainItemType" substitutionGroup="xbrli:item" />
  <element name="PurchaseMember" id="meec_PurchaseMember" nillable="true" xbrli:periodType="duration" type="nonnum:domainItemType" substitutionGroup="xbrli:item" />
  <element name="TwoSuppliersMember" id="meec_TwoSuppliersMember" nillable="true" xbrli:periodType="duration" type="nonnum:domainItemType" substitutionGroup="xbrli:item" />
  <element name="BottomMember" id="meec_BottomMember" nillable="true" xbrli:periodType="duration" type="nonnum:domainItemType" substitutionGroup="xbrli:item" />
  <element name="TopMember" id="meec_TopMember" nillable="true" xbrli:periodType="duration" type="nonnum:domainItemType" substitutionGroup="xbrli:item" />
  <element name="LicenseAndSettlementFeesMember" id="meec_LicenseAndSettlementFeesMember" nillable="true" xbrli:periodType="duration" type="nonnum:domainItemType" substitutionGroup="xbrli:item" />
  <element name="OneSuppliersMember" id="meec_OneSuppliersMember" nillable="true" xbrli:periodType="duration" type="nonnum:domainItemType" substitutionGroup="xbrli:item" />
</schema>
