<?xml version="1.0" encoding="UTF-8"?>

<!--XBRL Document Created with the Workiva Platform-->
<!--Copyright 2026 Workiva-->
<!--r:019f15c4-25b3-7714-a3d9-d1278d91d654,g:2e2935cc-6530-4d13-a0d3-8491fe122cd1-->
<link:linkbase 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" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd">
  <link:arcroleRef arcroleURI="https://xbrl.org/2023/arcrole/summation-item" xlink:type="simple" xlink:href="https://www.xbrl.org/2023/calculation-1.1.xsd#summation-item"/>
  <link:roleRef roleURI="http://essinc.com/role/CondensedConsolidatedBalanceSheets" xlink:type="simple" xlink:href="ghw-20260630.xsd#CondensedConsolidatedBalanceSheets"/>
  <link:calculationLink xlink:role="http://essinc.com/role/CondensedConsolidatedBalanceSheets" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_019f15c4-265a-7233-9457-a9026e7209d8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockholdersEquity"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockValue_019f15c4-265a-73d1-8215-c8671879083b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockValue"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_StockholdersEquity_019f15c4-265a-7233-9457-a9026e7209d8" xlink:to="loc_us-gaap_CommonStockValue_019f15c4-265a-73d1-8215-c8671879083b" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockValue_019f15c4-265a-7ee9-a1a1-bd1bfe11c3c3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PreferredStockValue"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_StockholdersEquity_019f15c4-265a-7233-9457-a9026e7209d8" xlink:to="loc_us-gaap_PreferredStockValue_019f15c4-265a-7ee9-a1a1-bd1bfe11c3c3" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdditionalPaidInCapital_019f15c4-265a-7ca5-9509-bfcdf6e34e03" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AdditionalPaidInCapital"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_StockholdersEquity_019f15c4-265a-7233-9457-a9026e7209d8" xlink:to="loc_us-gaap_AdditionalPaidInCapital_019f15c4-265a-7ca5-9509-bfcdf6e34e03" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetainedEarningsAccumulatedDeficit_019f15c4-265a-76fb-bc0a-63bac2351c7d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RetainedEarningsAccumulatedDeficit"/>
    <link:calculationArc order="4" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_StockholdersEquity_019f15c4-265a-7233-9457-a9026e7209d8" xlink:to="loc_us-gaap_RetainedEarningsAccumulatedDeficit_019f15c4-265a-76fb-bc0a-63bac2351c7d" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsCurrent_019f15c4-265a-713a-ace8-d220f0fa5669" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetsCurrent"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsReceivableNetCurrent_019f15c4-265a-718f-ab92-2cd56a086986" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccountsReceivableNetCurrent"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_AssetsCurrent_019f15c4-265a-713a-ace8-d220f0fa5669" xlink:to="loc_us-gaap_AccountsReceivableNetCurrent_019f15c4-265a-718f-ab92-2cd56a086986" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_019f15c4-265a-7a12-ba8b-35a91cc3d1fb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_AssetsCurrent_019f15c4-265a-713a-ace8-d220f0fa5669" xlink:to="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_019f15c4-265a-7a12-ba8b-35a91cc3d1fb" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedCashAndCashEquivalentsAtCarryingValue_019f15c4-265a-70fe-91f9-21340b070a4b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RestrictedCashAndCashEquivalentsAtCarryingValue"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_AssetsCurrent_019f15c4-265a-713a-ace8-d220f0fa5669" xlink:to="loc_us-gaap_RestrictedCashAndCashEquivalentsAtCarryingValue_019f15c4-265a-70fe-91f9-21340b070a4b" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TradingSecuritiesDebt_019f15c4-265a-73a6-9550-8f4d0efb0185" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TradingSecuritiesDebt"/>
    <link:calculationArc order="4" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_AssetsCurrent_019f15c4-265a-713a-ace8-d220f0fa5669" xlink:to="loc_us-gaap_TradingSecuritiesDebt_019f15c4-265a-73a6-9550-8f4d0efb0185" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PrepaidExpenseAndOtherAssetsCurrent_019f15c4-265a-75c5-840e-2ea753052077" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PrepaidExpenseAndOtherAssetsCurrent"/>
    <link:calculationArc order="5" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_AssetsCurrent_019f15c4-265a-713a-ace8-d220f0fa5669" xlink:to="loc_us-gaap_PrepaidExpenseAndOtherAssetsCurrent_019f15c4-265a-75c5-840e-2ea753052077" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InventoryNet_019f15c4-265a-79a9-9798-ede270f359ed" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InventoryNet"/>
    <link:calculationArc order="6" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_AssetsCurrent_019f15c4-265a-713a-ace8-d220f0fa5669" xlink:to="loc_us-gaap_InventoryNet_019f15c4-265a-79a9-9798-ede270f359ed" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Assets_019f15c4-265a-7b47-b5b5-2f4f324dc582" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Assets"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsCurrent_019f15c4-265a-72a4-82a2-50a854429c6a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetsCurrent"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_Assets_019f15c4-265a-7b47-b5b5-2f4f324dc582" xlink:to="loc_us-gaap_AssetsCurrent_019f15c4-265a-72a4-82a2-50a854429c6a" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherAssetsNoncurrent_019f15c4-265a-70aa-85a1-37ee4e320ca2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherAssetsNoncurrent"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_Assets_019f15c4-265a-7b47-b5b5-2f4f324dc582" xlink:to="loc_us-gaap_OtherAssetsNoncurrent_019f15c4-265a-70aa-85a1-37ee4e320ca2" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentNet_019f15c4-265a-73b2-9686-8c9c7b54c62d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentNet"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_Assets_019f15c4-265a-7b47-b5b5-2f4f324dc582" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentNet_019f15c4-265a-73b2-9686-8c9c7b54c62d" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedCashAndCashEquivalentsNoncurrent_019f15c4-265a-7a9f-b93f-91c029e87e44" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RestrictedCashAndCashEquivalentsNoncurrent"/>
    <link:calculationArc order="4" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_Assets_019f15c4-265a-7b47-b5b5-2f4f324dc582" xlink:to="loc_us-gaap_RestrictedCashAndCashEquivalentsNoncurrent_019f15c4-265a-7a9f-b93f-91c029e87e44" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseRightOfUseAsset_019f15c4-265a-7e5f-9105-8c9c758e2f5e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingLeaseRightOfUseAsset"/>
    <link:calculationArc order="5" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_Assets_019f15c4-265a-7b47-b5b5-2f4f324dc582" xlink:to="loc_us-gaap_OperatingLeaseRightOfUseAsset_019f15c4-265a-7e5f-9105-8c9c758e2f5e" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IntangibleAssetsNetExcludingGoodwill_019f15c4-265a-7d2d-9b37-6bb596aeef40" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IntangibleAssetsNetExcludingGoodwill"/>
    <link:calculationArc order="6" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_Assets_019f15c4-265a-7b47-b5b5-2f4f324dc582" xlink:to="loc_us-gaap_IntangibleAssetsNetExcludingGoodwill_019f15c4-265a-7d2d-9b37-6bb596aeef40" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquity_019f15c4-265a-7ebb-8a24-da3f686f8714" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LiabilitiesAndStockholdersEquity"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommitmentsAndContingencies_019f15c4-265a-75a8-b7db-e840c5064a24" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommitmentsAndContingencies"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquity_019f15c4-265a-7ebb-8a24-da3f686f8714" xlink:to="loc_us-gaap_CommitmentsAndContingencies_019f15c4-265a-75a8-b7db-e840c5064a24" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Liabilities_019f15c4-265a-72c1-b6d3-bc9ec14a2ee3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Liabilities"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquity_019f15c4-265a-7ebb-8a24-da3f686f8714" xlink:to="loc_us-gaap_Liabilities_019f15c4-265a-72c1-b6d3-bc9ec14a2ee3" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_019f15c4-265a-756d-ba8f-c98dcc52b2e0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockholdersEquity"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquity_019f15c4-265a-7ebb-8a24-da3f686f8714" xlink:to="loc_us-gaap_StockholdersEquity_019f15c4-265a-756d-ba8f-c98dcc52b2e0" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesCurrent_019f15c4-265a-70e5-ac2c-69ca73e9acff" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LiabilitiesCurrent"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProductWarrantyAccrualClassifiedCurrent_019f15c4-265a-7ff5-a86f-a83d27351689" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProductWarrantyAccrualClassifiedCurrent"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesCurrent_019f15c4-265a-70e5-ac2c-69ca73e9acff" xlink:to="loc_us-gaap_ProductWarrantyAccrualClassifiedCurrent_019f15c4-265a-7ff5-a86f-a83d27351689" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseLiabilityCurrent_019f15c4-265a-717e-af7c-05b257f47c4c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingLeaseLiabilityCurrent"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesCurrent_019f15c4-265a-70e5-ac2c-69ca73e9acff" xlink:to="loc_us-gaap_OperatingLeaseLiabilityCurrent_019f15c4-265a-717e-af7c-05b257f47c4c" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerLiabilityCurrent_019f15c4-265a-7693-95f2-cbc7c2807bba" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ContractWithCustomerLiabilityCurrent"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesCurrent_019f15c4-265a-70e5-ac2c-69ca73e9acff" xlink:to="loc_us-gaap_ContractWithCustomerLiabilityCurrent_019f15c4-265a-7693-95f2-cbc7c2807bba" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsPayableCurrent_019f15c4-265a-7477-b21f-4e23ef5e42cb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccountsPayableCurrent"/>
    <link:calculationArc order="4" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesCurrent_019f15c4-265a-70e5-ac2c-69ca73e9acff" xlink:to="loc_us-gaap_AccountsPayableCurrent_019f15c4-265a-7477-b21f-4e23ef5e42cb" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_ghw_AccruedLiabilitiesAndOtherCurrentLiabilities_019f15c4-265a-76e5-b7ab-9ee80f55e56b" xlink:href="ghw-20260630.xsd#ghw_AccruedLiabilitiesAndOtherCurrentLiabilities"/>
    <link:calculationArc order="5" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesCurrent_019f15c4-265a-70e5-ac2c-69ca73e9acff" xlink:to="loc_ghw_AccruedLiabilitiesAndOtherCurrentLiabilities_019f15c4-265a-76e5-b7ab-9ee80f55e56b" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseLiabilityCurrent_019f15c4-265a-732c-98a7-458f88b2863b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinanceLeaseLiabilityCurrent"/>
    <link:calculationArc order="6" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesCurrent_019f15c4-265a-70e5-ac2c-69ca73e9acff" xlink:to="loc_us-gaap_FinanceLeaseLiabilityCurrent_019f15c4-265a-732c-98a7-458f88b2863b" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Liabilities_019f15c4-265a-77cd-8c88-a3cbc941a7bb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Liabilities"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesCurrent_019f15c4-265a-7f12-8dd0-d01f758f0338" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LiabilitiesCurrent"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_Liabilities_019f15c4-265a-77cd-8c88-a3cbc941a7bb" xlink:to="loc_us-gaap_LiabilitiesCurrent_019f15c4-265a-7f12-8dd0-d01f758f0338" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseLiabilityNoncurrent_019f15c4-265a-7911-9318-5bde5bb0e52a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingLeaseLiabilityNoncurrent"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_Liabilities_019f15c4-265a-77cd-8c88-a3cbc941a7bb" xlink:to="loc_us-gaap_OperatingLeaseLiabilityNoncurrent_019f15c4-265a-7911-9318-5bde5bb0e52a" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerLiabilityNoncurrent_019f15c4-265a-71f7-a11a-ac9d5af6bab0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ContractWithCustomerLiabilityNoncurrent"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_Liabilities_019f15c4-265a-77cd-8c88-a3cbc941a7bb" xlink:to="loc_us-gaap_ContractWithCustomerLiabilityNoncurrent_019f15c4-265a-71f7-a11a-ac9d5af6bab0" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_ghw_CommonStockWarrantLiabilities_019f15c4-265a-7c32-9f9c-7bb5e525dd45" xlink:href="ghw-20260630.xsd#ghw_CommonStockWarrantLiabilities"/>
    <link:calculationArc order="4" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_Liabilities_019f15c4-265a-77cd-8c88-a3cbc941a7bb" xlink:to="loc_ghw_CommonStockWarrantLiabilities_019f15c4-265a-7c32-9f9c-7bb5e525dd45" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseLiabilityNoncurrent_019f15c4-265a-770b-8394-d82fa1cb129e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinanceLeaseLiabilityNoncurrent"/>
    <link:calculationArc order="5" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_Liabilities_019f15c4-265a-77cd-8c88-a3cbc941a7bb" xlink:to="loc_us-gaap_FinanceLeaseLiabilityNoncurrent_019f15c4-265a-770b-8394-d82fa1cb129e" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherLiabilitiesNoncurrent_019f15c4-265a-79c8-abd3-f7590d1a44f0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherLiabilitiesNoncurrent"/>
    <link:calculationArc order="6" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_Liabilities_019f15c4-265a-77cd-8c88-a3cbc941a7bb" xlink:to="loc_us-gaap_OtherLiabilitiesNoncurrent_019f15c4-265a-79c8-abd3-f7590d1a44f0" xlink:type="arc"/>
  </link:calculationLink>
  <link:roleRef roleURI="http://essinc.com/role/CondensedConsolidatedStatementsofOperationsandComprehensiveLoss" xlink:type="simple" xlink:href="ghw-20260630.xsd#CondensedConsolidatedStatementsofOperationsandComprehensiveLoss"/>
  <link:calculationLink xlink:role="http://essinc.com/role/CondensedConsolidatedStatementsofOperationsandComprehensiveLoss" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_019f15c4-265a-788a-bd75-9f62acd6265c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetIncomeLoss"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingIncomeLoss_019f15c4-265a-778d-9214-20fc64011214" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingIncomeLoss"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetIncomeLoss_019f15c4-265a-788a-bd75-9f62acd6265c" xlink:to="loc_us-gaap_OperatingIncomeLoss_019f15c4-265a-778d-9214-20fc64011214" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NonoperatingIncomeExpense_019f15c4-265a-7412-aeb5-597593ecbf17" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NonoperatingIncomeExpense"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetIncomeLoss_019f15c4-265a-788a-bd75-9f62acd6265c" xlink:to="loc_us-gaap_NonoperatingIncomeExpense_019f15c4-265a-7412-aeb5-597593ecbf17" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ComprehensiveIncomeNetOfTax_019f15c4-265a-761d-a162-45b093546ce5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ComprehensiveIncomeNetOfTax"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NonoperatingIncomeExpense_019f15c4-265a-71dc-a83c-1bf8694d042a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NonoperatingIncomeExpense"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_ComprehensiveIncomeNetOfTax_019f15c4-265a-761d-a162-45b093546ce5" xlink:to="loc_us-gaap_NonoperatingIncomeExpense_019f15c4-265a-71dc-a83c-1bf8694d042a" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingIncomeLoss_019f15c4-265a-77b2-9064-3f3f5ac8506c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingIncomeLoss"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_ComprehensiveIncomeNetOfTax_019f15c4-265a-761d-a162-45b093546ce5" xlink:to="loc_us-gaap_OperatingIncomeLoss_019f15c4-265a-77b2-9064-3f3f5ac8506c" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NonoperatingIncomeExpense_019f15c4-265a-7185-9e42-ca77a5f3e9e0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NonoperatingIncomeExpense"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestIncomeExpenseNonoperatingNet_019f15c4-265a-73c7-ad32-68d0e4166c56" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestIncomeExpenseNonoperatingNet"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NonoperatingIncomeExpense_019f15c4-265a-7185-9e42-ca77a5f3e9e0" xlink:to="loc_us-gaap_InterestIncomeExpenseNonoperatingNet_019f15c4-265a-73c7-ad32-68d0e4166c56" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAdjustmentOfWarrants_019f15c4-265a-7e6e-b1f6-4d591e004cc9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueAdjustmentOfWarrants"/>
    <link:calculationArc order="2" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NonoperatingIncomeExpense_019f15c4-265a-7185-9e42-ca77a5f3e9e0" xlink:to="loc_us-gaap_FairValueAdjustmentOfWarrants_019f15c4-265a-7e6e-b1f6-4d591e004cc9" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherNonoperatingIncomeExpense_019f15c4-265a-7f8b-8135-5d1f89182b18" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherNonoperatingIncomeExpense"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NonoperatingIncomeExpense_019f15c4-265a-7185-9e42-ca77a5f3e9e0" xlink:to="loc_us-gaap_OtherNonoperatingIncomeExpense_019f15c4-265a-7f8b-8135-5d1f89182b18" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingIncomeLoss_019f15c4-265a-7681-9c67-44fa957ed4f8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingIncomeLoss"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingExpenses_019f15c4-265a-7018-9237-2fef5885a1dd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingExpenses"/>
    <link:calculationArc order="1" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_OperatingIncomeLoss_019f15c4-265a-7681-9c67-44fa957ed4f8" xlink:to="loc_us-gaap_OperatingExpenses_019f15c4-265a-7018-9237-2fef5885a1dd" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GrossProfit_019f15c4-265a-7c14-96a9-0875bb0e3c66" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_GrossProfit"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_OperatingIncomeLoss_019f15c4-265a-7681-9c67-44fa957ed4f8" xlink:to="loc_us-gaap_GrossProfit_019f15c4-265a-7c14-96a9-0875bb0e3c66" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GrossProfit_019f15c4-265a-7370-8fbc-9e7b1fad6fc7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_GrossProfit"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_019f15c4-265a-7f3e-8a90-b818820ade6d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_GrossProfit_019f15c4-265a-7370-8fbc-9e7b1fad6fc7" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_019f15c4-265a-7f3e-8a90-b818820ade6d" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostOfRevenue_019f15c4-265a-76e8-b9fd-a6be069e0785" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CostOfRevenue"/>
    <link:calculationArc order="2" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_GrossProfit_019f15c4-265a-7370-8fbc-9e7b1fad6fc7" xlink:to="loc_us-gaap_CostOfRevenue_019f15c4-265a-76e8-b9fd-a6be069e0785" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingExpenses_019f15c4-265a-7ba7-bd59-eb540eae7ba2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingExpenses"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResearchAndDevelopmentExpense_019f15c4-265a-7896-92ac-7356ecc78334" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ResearchAndDevelopmentExpense"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_OperatingExpenses_019f15c4-265a-7ba7-bd59-eb540eae7ba2" xlink:to="loc_us-gaap_ResearchAndDevelopmentExpense_019f15c4-265a-7896-92ac-7356ecc78334" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SellingAndMarketingExpense_019f15c4-265a-779f-9687-a88426ad431f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SellingAndMarketingExpense"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_OperatingExpenses_019f15c4-265a-7ba7-bd59-eb540eae7ba2" xlink:to="loc_us-gaap_SellingAndMarketingExpense_019f15c4-265a-779f-9687-a88426ad431f" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GeneralAndAdministrativeExpense_019f15c4-265a-7633-9144-682844ef0254" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_GeneralAndAdministrativeExpense"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_OperatingExpenses_019f15c4-265a-7ba7-bd59-eb540eae7ba2" xlink:to="loc_us-gaap_GeneralAndAdministrativeExpense_019f15c4-265a-7633-9144-682844ef0254" xlink:type="arc"/>
  </link:calculationLink>
  <link:roleRef roleURI="http://essinc.com/role/CondensedConsolidatedStatementsofCashFlows" xlink:type="simple" xlink:href="ghw-20260630.xsd#CondensedConsolidatedStatementsofCashFlows"/>
  <link:calculationLink xlink:role="http://essinc.com/role/CondensedConsolidatedStatementsofCashFlows" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect_019f15c4-265a-71f8-81e2-4377da86b953" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_019f15c4-265a-7b59-819a-29d17d9a440f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivities"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect_019f15c4-265a-71f8-81e2-4377da86b953" xlink:to="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_019f15c4-265a-7b59-819a-29d17d9a440f" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_019f15c4-265a-7460-83ad-8608c0bcbff4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivities"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect_019f15c4-265a-71f8-81e2-4377da86b953" xlink:to="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_019f15c4-265a-7460-83ad-8608c0bcbff4" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_019f15c4-265a-7903-90fe-f32a79f7defd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivities"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect_019f15c4-265a-71f8-81e2-4377da86b953" xlink:to="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_019f15c4-265a-7903-90fe-f32a79f7defd" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_019f15c4-265a-7aca-a653-3d139506d203" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivities"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromIssuanceOfCommonStock_019f15c4-265a-7205-ba10-2388b5ff8bea" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProceedsFromIssuanceOfCommonStock"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_019f15c4-265a-7aca-a653-3d139506d203" xlink:to="loc_us-gaap_ProceedsFromIssuanceOfCommonStock_019f15c4-265a-7205-ba10-2388b5ff8bea" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromIssuanceOfWarrants_019f15c4-265a-7d43-90cb-257546504d08" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProceedsFromIssuanceOfWarrants"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_019f15c4-265a-7aca-a653-3d139506d203" xlink:to="loc_us-gaap_ProceedsFromIssuanceOfWarrants_019f15c4-265a-7d43-90cb-257546504d08" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_ghw_ProceedsFromFinancingArrangements_019f15c4-265a-720a-b383-b3df19a1b1c5" xlink:href="ghw-20260630.xsd#ghw_ProceedsFromFinancingArrangements"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_019f15c4-265a-7aca-a653-3d139506d203" xlink:to="loc_ghw_ProceedsFromFinancingArrangements_019f15c4-265a-720a-b383-b3df19a1b1c5" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsOfLoanCosts_019f15c4-265a-7791-beb5-b6e3e0b171f8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PaymentsOfLoanCosts"/>
    <link:calculationArc order="4" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_019f15c4-265a-7aca-a653-3d139506d203" xlink:to="loc_us-gaap_PaymentsOfLoanCosts_019f15c4-265a-7791-beb5-b6e3e0b171f8" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromStockOptionsExercised_019f15c4-265a-7f2f-8de0-368be304c784" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProceedsFromStockOptionsExercised"/>
    <link:calculationArc order="5" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_019f15c4-265a-7aca-a653-3d139506d203" xlink:to="loc_us-gaap_ProceedsFromStockOptionsExercised_019f15c4-265a-7f2f-8de0-368be304c784" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromStockPlans_019f15c4-265a-79f4-8c2d-d804cb544b6d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProceedsFromStockPlans"/>
    <link:calculationArc order="6" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_019f15c4-265a-7aca-a653-3d139506d203" xlink:to="loc_us-gaap_ProceedsFromStockPlans_019f15c4-265a-79f4-8c2d-d804cb544b6d" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsRelatedToTaxWithholdingForShareBasedCompensation_019fb309-bd50-714a-bf9c-9637e7d6b8fa" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PaymentsRelatedToTaxWithholdingForShareBasedCompensation"/>
    <link:calculationArc order="7" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_019f15c4-265a-7aca-a653-3d139506d203" xlink:to="loc_us-gaap_PaymentsRelatedToTaxWithholdingForShareBasedCompensation_019fb309-bd50-714a-bf9c-9637e7d6b8fa" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_019f15c4-265a-749f-b3f0-b66d1796afb1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedCashAndCashEquivalentsNoncurrent_019f15c4-265a-7014-abfa-2187c025e1ec" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RestrictedCashAndCashEquivalentsNoncurrent"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_019f15c4-265a-749f-b3f0-b66d1796afb1" xlink:to="loc_us-gaap_RestrictedCashAndCashEquivalentsNoncurrent_019f15c4-265a-7014-abfa-2187c025e1ec" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_019f15c4-265a-71c9-8ba8-ed7de508356b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_019f15c4-265a-749f-b3f0-b66d1796afb1" xlink:to="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_019f15c4-265a-71c9-8ba8-ed7de508356b" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedCashAndCashEquivalentsAtCarryingValue_019f15c4-265a-7702-a447-389323f1ad60" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RestrictedCashAndCashEquivalentsAtCarryingValue"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_019f15c4-265a-749f-b3f0-b66d1796afb1" xlink:to="loc_us-gaap_RestrictedCashAndCashEquivalentsAtCarryingValue_019f15c4-265a-7702-a447-389323f1ad60" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_019f15c4-265a-700c-b409-3493e51287bd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivities"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsForProceedsFromShortTermInvestments_019f15c4-265a-774c-b1e3-9af0f019f5a8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PaymentsForProceedsFromShortTermInvestments"/>
    <link:calculationArc order="1" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_019f15c4-265a-700c-b409-3493e51287bd" xlink:to="loc_us-gaap_PaymentsForProceedsFromShortTermInvestments_019f15c4-265a-774c-b1e3-9af0f019f5a8" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_019f15c4-265a-7c4e-8078-de2f4f9c5ca0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PaymentsToAcquirePropertyPlantAndEquipment"/>
    <link:calculationArc order="2" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_019f15c4-265a-700c-b409-3493e51287bd" xlink:to="loc_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_019f15c4-265a-7c4e-8078-de2f4f9c5ca0" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_019f15c4-265a-734b-a924-77bf8000e22b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivities"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_019f15c4-265a-7a8b-aaac-f4ca89dc7c2f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetIncomeLoss"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_019f15c4-265a-734b-a924-77bf8000e22b" xlink:to="loc_us-gaap_NetIncomeLoss_019f15c4-265a-7a8b-aaac-f4ca89dc7c2f" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DepreciationDepletionAndAmortization_019f15c4-265a-72de-873c-4a5bc019a632" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DepreciationDepletionAndAmortization"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_019f15c4-265a-734b-a924-77bf8000e22b" xlink:to="loc_us-gaap_DepreciationDepletionAndAmortization_019f15c4-265a-72de-873c-4a5bc019a632" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_ghw_AssetAbandonment_019f15c4-265a-7601-b080-56b7382e785a" xlink:href="ghw-20260630.xsd#ghw_AssetAbandonment"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_019f15c4-265a-734b-a924-77bf8000e22b" xlink:to="loc_ghw_AssetAbandonment_019f15c4-265a-7601-b080-56b7382e785a" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_ghw_NonCashInterestIncome_019f15c4-265a-711f-bca9-c7e2dfc751b6" xlink:href="ghw-20260630.xsd#ghw_NonCashInterestIncome"/>
    <link:calculationArc order="4" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_019f15c4-265a-734b-a924-77bf8000e22b" xlink:to="loc_ghw_NonCashInterestIncome_019f15c4-265a-711f-bca9-c7e2dfc751b6" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_ghw_NoncashOperatingLeaseExpense_019f15c4-265a-7059-bc99-985e77113c16" xlink:href="ghw-20260630.xsd#ghw_NoncashOperatingLeaseExpense"/>
    <link:calculationArc order="5" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_019f15c4-265a-734b-a924-77bf8000e22b" xlink:to="loc_ghw_NoncashOperatingLeaseExpense_019f15c4-265a-7059-bc99-985e77113c16" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensation_019f15c4-265a-77e2-bb46-7192df68224b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensation"/>
    <link:calculationArc order="6" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_019f15c4-265a-734b-a924-77bf8000e22b" xlink:to="loc_us-gaap_ShareBasedCompensation_019f15c4-265a-77e2-bb46-7192df68224b" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAdjustmentOfWarrants_019f15c4-265a-7e24-9b83-779457e74f73" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueAdjustmentOfWarrants"/>
    <link:calculationArc order="7" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_019f15c4-265a-734b-a924-77bf8000e22b" xlink:to="loc_us-gaap_FairValueAdjustmentOfWarrants_019f15c4-265a-7e24-9b83-779457e74f73" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherNoncashIncomeExpense_019f15c4-265a-74bd-9313-128ac20fc406" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherNoncashIncomeExpense"/>
    <link:calculationArc order="8" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_019f15c4-265a-734b-a924-77bf8000e22b" xlink:to="loc_us-gaap_OtherNoncashIncomeExpense_019f15c4-265a-74bd-9313-128ac20fc406" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInAccountsReceivable_019f15c4-265a-7912-a887-21740aa13e33" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncreaseDecreaseInAccountsReceivable"/>
    <link:calculationArc order="9" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_019f15c4-265a-734b-a924-77bf8000e22b" xlink:to="loc_us-gaap_IncreaseDecreaseInAccountsReceivable_019f15c4-265a-7912-a887-21740aa13e33" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInInventories_019f15c4-265a-706a-bbc2-402feb0de552" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncreaseDecreaseInInventories"/>
    <link:calculationArc order="10" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_019f15c4-265a-734b-a924-77bf8000e22b" xlink:to="loc_us-gaap_IncreaseDecreaseInInventories_019f15c4-265a-706a-bbc2-402feb0de552" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets_019f15c4-265a-7d3c-b7cd-06627a647889" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets"/>
    <link:calculationArc order="11" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_019f15c4-265a-734b-a924-77bf8000e22b" xlink:to="loc_us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets_019f15c4-265a-7d3c-b7cd-06627a647889" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInAccountsPayable_019f15c4-265a-7b23-8eac-0c7abd4b6956" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncreaseDecreaseInAccountsPayable"/>
    <link:calculationArc order="12" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_019f15c4-265a-734b-a924-77bf8000e22b" xlink:to="loc_us-gaap_IncreaseDecreaseInAccountsPayable_019f15c4-265a-7b23-8eac-0c7abd4b6956" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_ghw_IncreaseDecreaseInAccruedLiabilitiesAndOtherCurrentLiabilities_019f15c4-265a-7213-acbe-59fd047c6910" xlink:href="ghw-20260630.xsd#ghw_IncreaseDecreaseInAccruedLiabilitiesAndOtherCurrentLiabilities"/>
    <link:calculationArc order="13" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_019f15c4-265a-734b-a924-77bf8000e22b" xlink:to="loc_ghw_IncreaseDecreaseInAccruedLiabilitiesAndOtherCurrentLiabilities_019f15c4-265a-7213-acbe-59fd047c6910" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_ghw_IncreaseDecreaseInProductWarrantyAccrual_019f15c4-265a-7a46-b377-7205c0f57654" xlink:href="ghw-20260630.xsd#ghw_IncreaseDecreaseInProductWarrantyAccrual"/>
    <link:calculationArc order="14" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_019f15c4-265a-734b-a924-77bf8000e22b" xlink:to="loc_ghw_IncreaseDecreaseInProductWarrantyAccrual_019f15c4-265a-7a46-b377-7205c0f57654" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInContractWithCustomerLiability_019f15c4-265a-7555-96cd-f2f12c8cfa10" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncreaseDecreaseInContractWithCustomerLiability"/>
    <link:calculationArc order="15" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_019f15c4-265a-734b-a924-77bf8000e22b" xlink:to="loc_us-gaap_IncreaseDecreaseInContractWithCustomerLiability_019f15c4-265a-7555-96cd-f2f12c8cfa10" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInOperatingLeaseLiability_019fb2b0-d511-781b-8f05-3c0e4cc34053" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncreaseDecreaseInOperatingLeaseLiability"/>
    <link:calculationArc order="16" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_019f15c4-265a-734b-a924-77bf8000e22b" xlink:to="loc_us-gaap_IncreaseDecreaseInOperatingLeaseLiability_019fb2b0-d511-781b-8f05-3c0e4cc34053" xlink:type="arc"/>
  </link:calculationLink>
  <link:roleRef roleURI="http://essinc.com/role/INVENTORYScheduleofInventoryDetails" xlink:type="simple" xlink:href="ghw-20260630.xsd#INVENTORYScheduleofInventoryDetails"/>
  <link:calculationLink xlink:role="http://essinc.com/role/INVENTORYScheduleofInventoryDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InventoryNet_019f15c4-2712-7506-8abd-a1f271860796" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InventoryNet"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InventoryValuationReserves_019f15c4-2712-7492-b92a-d16cfae29642" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InventoryValuationReserves"/>
    <link:calculationArc order="1" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_InventoryNet_019f15c4-2712-7506-8abd-a1f271860796" xlink:to="loc_us-gaap_InventoryValuationReserves_019f15c4-2712-7492-b92a-d16cfae29642" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InventoryGross_019f15c4-2712-7808-8677-aba3da78fa12" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InventoryGross"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_InventoryNet_019f15c4-2712-7506-8abd-a1f271860796" xlink:to="loc_us-gaap_InventoryGross_019f15c4-2712-7808-8677-aba3da78fa12" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InventoryGross_019f15c4-2712-7be6-9c89-502f1c2b1669" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InventoryGross"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InventoryRawMaterials_019f15c4-2712-70bf-9686-19588251d491" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InventoryRawMaterials"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_InventoryGross_019f15c4-2712-7be6-9c89-502f1c2b1669" xlink:to="loc_us-gaap_InventoryRawMaterials_019f15c4-2712-70bf-9686-19588251d491" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InventoryWorkInProcess_019f15c4-2712-74f9-9f91-739512158bdf" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InventoryWorkInProcess"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_InventoryGross_019f15c4-2712-7be6-9c89-502f1c2b1669" xlink:to="loc_us-gaap_InventoryWorkInProcess_019f15c4-2712-74f9-9f91-739512158bdf" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InventoryFinishedGoods_019f15c4-2712-77dd-92b5-f5d26cd21cad" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InventoryFinishedGoods"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_InventoryGross_019f15c4-2712-7be6-9c89-502f1c2b1669" xlink:to="loc_us-gaap_InventoryFinishedGoods_019f15c4-2712-77dd-92b5-f5d26cd21cad" xlink:type="arc"/>
  </link:calculationLink>
  <link:roleRef roleURI="http://essinc.com/role/PROPERTYANDEQUIPMENTNETDetails" xlink:type="simple" xlink:href="ghw-20260630.xsd#PROPERTYANDEQUIPMENTNETDetails"/>
  <link:calculationLink xlink:role="http://essinc.com/role/PROPERTYANDEQUIPMENTNETDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentNet_019f15c4-2712-7fd2-9a77-99dda45a962f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentNet"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentGross_019f15c4-2712-7cef-9d27-35c12bb88fcc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentGross"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentNet_019f15c4-2712-7fd2-9a77-99dda45a962f" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentGross_019f15c4-2712-7cef-9d27-35c12bb88fcc" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_019f15c4-2712-79a9-aa18-9df0681c5b2c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment"/>
    <link:calculationArc order="2" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentNet_019f15c4-2712-7fd2-9a77-99dda45a962f" xlink:to="loc_us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_019f15c4-2712-79a9-aa18-9df0681c5b2c" xlink:type="arc"/>
  </link:calculationLink>
  <link:roleRef roleURI="http://essinc.com/role/INTANGIBLEASSETSNETScheduleofIntangibleAssetsNetDetails" xlink:type="simple" xlink:href="ghw-20260630.xsd#INTANGIBLEASSETSNETScheduleofIntangibleAssetsNetDetails"/>
  <link:calculationLink xlink:role="http://essinc.com/role/INTANGIBLEASSETSNETScheduleofIntangibleAssetsNetDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherIntangibleAssetsNet_019f15c4-2712-7519-9c1b-3241ef6b8f52" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherIntangibleAssetsNet"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherFiniteLivedIntangibleAssetsGross_019f15c4-2712-7bd2-8ebf-2415d2bab56d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherFiniteLivedIntangibleAssetsGross"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_OtherIntangibleAssetsNet_019f15c4-2712-7519-9c1b-3241ef6b8f52" xlink:to="loc_us-gaap_OtherFiniteLivedIntangibleAssetsGross_019f15c4-2712-7bd2-8ebf-2415d2bab56d" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_019f15c4-2712-7572-9551-311123f89598" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization"/>
    <link:calculationArc order="2" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_OtherIntangibleAssetsNet_019f15c4-2712-7519-9c1b-3241ef6b8f52" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_019f15c4-2712-7572-9551-311123f89598" xlink:type="arc"/>
  </link:calculationLink>
  <link:roleRef roleURI="http://essinc.com/role/ACCRUEDANDOTHERCURRENTLIABILITIESDetails" xlink:type="simple" xlink:href="ghw-20260630.xsd#ACCRUEDANDOTHERCURRENTLIABILITIESDetails"/>
  <link:calculationLink xlink:role="http://essinc.com/role/ACCRUEDANDOTHERCURRENTLIABILITIESDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_ghw_AccruedLiabilitiesAndOtherCurrentLiabilities_019f15c4-2712-7e79-ae23-4a13c7b517be" xlink:href="ghw-20260630.xsd#ghw_AccruedLiabilitiesAndOtherCurrentLiabilities"/>
    <link:loc xlink:type="locator" xlink:label="loc_ghw_MaterialsAndRelatedPurchasesCurrent_019f15c4-2712-782e-bd03-000903917b39" xlink:href="ghw-20260630.xsd#ghw_MaterialsAndRelatedPurchasesCurrent"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_ghw_AccruedLiabilitiesAndOtherCurrentLiabilities_019f15c4-2712-7e79-ae23-4a13c7b517be" xlink:to="loc_ghw_MaterialsAndRelatedPurchasesCurrent_019f15c4-2712-782e-bd03-000903917b39" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_ghw_OtherAccruedLiabilityAndOtherLiabilitiesCurrent_019f15c4-2712-767a-a61b-c6660d45faeb" xlink:href="ghw-20260630.xsd#ghw_OtherAccruedLiabilityAndOtherLiabilitiesCurrent"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_ghw_AccruedLiabilitiesAndOtherCurrentLiabilities_019f15c4-2712-7e79-ae23-4a13c7b517be" xlink:to="loc_ghw_OtherAccruedLiabilityAndOtherLiabilitiesCurrent_019f15c4-2712-767a-a61b-c6660d45faeb" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeRelatedLiabilitiesCurrent_019f15c4-2712-7330-850a-24a39a46bd5b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EmployeeRelatedLiabilitiesCurrent"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_ghw_AccruedLiabilitiesAndOtherCurrentLiabilities_019f15c4-2712-7e79-ae23-4a13c7b517be" xlink:to="loc_us-gaap_EmployeeRelatedLiabilitiesCurrent_019f15c4-2712-7330-850a-24a39a46bd5b" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccruedProfessionalFeesCurrent_019f15c4-2712-71df-bb16-534c52dea8f5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccruedProfessionalFeesCurrent"/>
    <link:calculationArc order="4" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_ghw_AccruedLiabilitiesAndOtherCurrentLiabilities_019f15c4-2712-7e79-ae23-4a13c7b517be" xlink:to="loc_us-gaap_AccruedProfessionalFeesCurrent_019f15c4-2712-71df-bb16-534c52dea8f5" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_ghw_EnvironmentalHealthSafetyComplianceLiability_019f15c4-2712-7087-8ebd-f1b5d1b851c9" xlink:href="ghw-20260630.xsd#ghw_EnvironmentalHealthSafetyComplianceLiability"/>
    <link:calculationArc order="5" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_ghw_AccruedLiabilitiesAndOtherCurrentLiabilities_019f15c4-2712-7e79-ae23-4a13c7b517be" xlink:to="loc_ghw_EnvironmentalHealthSafetyComplianceLiability_019f15c4-2712-7087-8ebd-f1b5d1b851c9" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CustomerRefundLiabilityCurrent_019f15c4-2712-70e0-ae5e-cb68b93b1f9f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CustomerRefundLiabilityCurrent"/>
    <link:calculationArc order="6" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_ghw_AccruedLiabilitiesAndOtherCurrentLiabilities_019f15c4-2712-7e79-ae23-4a13c7b517be" xlink:to="loc_us-gaap_CustomerRefundLiabilityCurrent_019f15c4-2712-70e0-ae5e-cb68b93b1f9f" xlink:type="arc"/>
  </link:calculationLink>
  <link:roleRef roleURI="http://essinc.com/role/FINANCINGOBLIGATIONSScheduleofRemainingFutureCashPaymentsDetails" xlink:type="simple" xlink:href="ghw-20260630.xsd#FINANCINGOBLIGATIONSScheduleofRemainingFutureCashPaymentsDetails"/>
  <link:calculationLink xlink:role="http://essinc.com/role/FINANCINGOBLIGATIONSScheduleofRemainingFutureCashPaymentsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseLiabilityPaymentsDue_019f15c4-2713-7b16-9d05-d354dbd6a9a7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinanceLeaseLiabilityPaymentsDue"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseLiabilityPaymentsRemainderOfFiscalYear_019f15c4-2713-7018-bf2a-632be22f2ff4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinanceLeaseLiabilityPaymentsRemainderOfFiscalYear"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_FinanceLeaseLiabilityPaymentsDue_019f15c4-2713-7b16-9d05-d354dbd6a9a7" xlink:to="loc_us-gaap_FinanceLeaseLiabilityPaymentsRemainderOfFiscalYear_019f15c4-2713-7018-bf2a-632be22f2ff4" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseLiabilityPaymentsDueNextTwelveMonths_019f15c4-2713-7971-8467-794154ae1f6a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinanceLeaseLiabilityPaymentsDueNextTwelveMonths"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_FinanceLeaseLiabilityPaymentsDue_019f15c4-2713-7b16-9d05-d354dbd6a9a7" xlink:to="loc_us-gaap_FinanceLeaseLiabilityPaymentsDueNextTwelveMonths_019f15c4-2713-7971-8467-794154ae1f6a" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseLiabilityPaymentsDueYearTwo_019f15c4-2713-7f1d-ac41-e3eb793f8dc9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinanceLeaseLiabilityPaymentsDueYearTwo"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_FinanceLeaseLiabilityPaymentsDue_019f15c4-2713-7b16-9d05-d354dbd6a9a7" xlink:to="loc_us-gaap_FinanceLeaseLiabilityPaymentsDueYearTwo_019f15c4-2713-7f1d-ac41-e3eb793f8dc9" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseLiabilityPaymentsDueYearThree_019f15c4-2713-74d9-9bdc-64a0d855074b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinanceLeaseLiabilityPaymentsDueYearThree"/>
    <link:calculationArc order="4" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_FinanceLeaseLiabilityPaymentsDue_019f15c4-2713-7b16-9d05-d354dbd6a9a7" xlink:to="loc_us-gaap_FinanceLeaseLiabilityPaymentsDueYearThree_019f15c4-2713-74d9-9bdc-64a0d855074b" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseLiabilityPaymentsDueYearFour_019f15c4-2713-7e0b-8676-e8dc5640964f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinanceLeaseLiabilityPaymentsDueYearFour"/>
    <link:calculationArc order="5" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_FinanceLeaseLiabilityPaymentsDue_019f15c4-2713-7b16-9d05-d354dbd6a9a7" xlink:to="loc_us-gaap_FinanceLeaseLiabilityPaymentsDueYearFour_019f15c4-2713-7e0b-8676-e8dc5640964f" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_ghw_FinanceLeaseLiabilityPaymentsDueAfterYearFour_019f15c4-2713-7077-be19-c65e9ad93122" xlink:href="ghw-20260630.xsd#ghw_FinanceLeaseLiabilityPaymentsDueAfterYearFour"/>
    <link:calculationArc order="6" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_FinanceLeaseLiabilityPaymentsDue_019f15c4-2713-7b16-9d05-d354dbd6a9a7" xlink:to="loc_ghw_FinanceLeaseLiabilityPaymentsDueAfterYearFour_019f15c4-2713-7077-be19-c65e9ad93122" xlink:type="arc"/>
  </link:calculationLink>
  <link:roleRef roleURI="http://essinc.com/role/FAIRVALUEMEASUREMENTSDetails" xlink:type="simple" xlink:href="ghw-20260630.xsd#FAIRVALUEMEASUREMENTSDetails"/>
  <link:calculationLink xlink:role="http://essinc.com/role/FAIRVALUEMEASUREMENTSDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesFairValueDisclosure_019f15c4-2713-733f-8934-831d320b888b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LiabilitiesFairValueDisclosure"/>
    <link:loc xlink:type="locator" xlink:label="loc_ghw_CommonStockWarrantsFairValueDisclosure_019f15c4-2713-7d25-ab0b-ac19e87ccc15" xlink:href="ghw-20260630.xsd#ghw_CommonStockWarrantsFairValueDisclosure"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesFairValueDisclosure_019f15c4-2713-733f-8934-831d320b888b" xlink:to="loc_ghw_CommonStockWarrantsFairValueDisclosure_019f15c4-2713-7d25-ab0b-ac19e87ccc15" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsFairValueDisclosure_019f15c4-2713-720c-86e3-b116c6a86053" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetsFairValueDisclosure"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TradingSecuritiesDebt_019f15c4-2713-7894-aa43-38ec18c0429b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TradingSecuritiesDebt"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_AssetsFairValueDisclosure_019f15c4-2713-720c-86e3-b116c6a86053" xlink:to="loc_us-gaap_TradingSecuritiesDebt_019f15c4-2713-7894-aa43-38ec18c0429b" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsFairValueDisclosure_019f15c4-2713-7952-a752-fb27bcb81187" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CashAndCashEquivalentsFairValueDisclosure"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_AssetsFairValueDisclosure_019f15c4-2713-720c-86e3-b116c6a86053" xlink:to="loc_us-gaap_CashAndCashEquivalentsFairValueDisclosure_019f15c4-2713-7952-a752-fb27bcb81187" xlink:type="arc"/>
  </link:calculationLink>
</link:linkbase>
