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

<!--XBRL Document Created with the Workiva Platform-->
<!--Copyright 2026 Workiva-->
<!--r:019ed6c3-a16c-7f80-b1ae-af288603c64a,g:948251e0-ce5c-43fd-9b3b-c7446e52f45d-->
<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://www.nisource.com/role/StatementsofConsolidatedIncomeLoss" xlink:type="simple" xlink:href="nix-20260630.xsd#StatementsofConsolidatedIncomeLoss"/>
  <link:calculationLink xlink:role="http://www.nisource.com/role/StatementsofConsolidatedIncomeLoss" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingCostsAndExpenses_019ed6c3-a36f-7551-bd1a-13ea01fe3c08" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingCostsAndExpenses"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostOfGoodsAndServiceExcludingDepreciationDepletionAndAmortization_019ed6c3-a36f-77b8-8767-41c03c6c73b3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CostOfGoodsAndServiceExcludingDepreciationDepletionAndAmortization"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_OperatingCostsAndExpenses_019ed6c3-a36f-7551-bd1a-13ea01fe3c08" xlink:to="loc_us-gaap_CostOfGoodsAndServiceExcludingDepreciationDepletionAndAmortization_019ed6c3-a36f-77b8-8767-41c03c6c73b3" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UtilitiesOperatingExpenseMaintenanceAndOperations_019ed6c3-a36f-7c66-9ffc-dacf5e78755f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_UtilitiesOperatingExpenseMaintenanceAndOperations"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_OperatingCostsAndExpenses_019ed6c3-a36f-7551-bd1a-13ea01fe3c08" xlink:to="loc_us-gaap_UtilitiesOperatingExpenseMaintenanceAndOperations_019ed6c3-a36f-7c66-9ffc-dacf5e78755f" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DepreciationDepletionAndAmortization_019ed6c3-a36f-7a20-b68e-55177bd0fd8a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DepreciationDepletionAndAmortization"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_OperatingCostsAndExpenses_019ed6c3-a36f-7551-bd1a-13ea01fe3c08" xlink:to="loc_us-gaap_DepreciationDepletionAndAmortization_019ed6c3-a36f-7a20-b68e-55177bd0fd8a" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_nix_ImpairmentAndGainLossOnSaleOfAssetsNet_019ed6c3-a36f-7244-b65f-f270f33cf8a9" xlink:href="nix-20260630.xsd#nix_ImpairmentAndGainLossOnSaleOfAssetsNet"/>
    <link:calculationArc order="4" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_OperatingCostsAndExpenses_019ed6c3-a36f-7551-bd1a-13ea01fe3c08" xlink:to="loc_nix_ImpairmentAndGainLossOnSaleOfAssetsNet_019ed6c3-a36f-7244-b65f-f270f33cf8a9" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainLossOnSaleOfOtherAssets_019ed6c3-a36f-727f-8a90-4bb99dac7305" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_GainLossOnSaleOfOtherAssets"/>
    <link:calculationArc order="5" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_OperatingCostsAndExpenses_019ed6c3-a36f-7551-bd1a-13ea01fe3c08" xlink:to="loc_us-gaap_GainLossOnSaleOfOtherAssets_019ed6c3-a36f-727f-8a90-4bb99dac7305" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TaxesExcludingIncomeAndExciseTaxes_019ed6c3-a36f-714a-a7f0-6b5bf78e7b5a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TaxesExcludingIncomeAndExciseTaxes"/>
    <link:calculationArc order="6" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_OperatingCostsAndExpenses_019ed6c3-a36f-7551-bd1a-13ea01fe3c08" xlink:to="loc_us-gaap_TaxesExcludingIncomeAndExciseTaxes_019ed6c3-a36f-714a-a7f0-6b5bf78e7b5a" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic_019ed6c3-a36f-7f9c-a7d5-94b7ae8bed1f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_019ed6c3-a36f-7498-af1c-804af959f343" 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_NetIncomeLossAvailableToCommonStockholdersBasic_019ed6c3-a36f-7f9c-a7d5-94b7ae8bed1f" xlink:to="loc_us-gaap_NetIncomeLoss_019ed6c3-a36f-7498-af1c-804af959f343" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_nix_PreferredDividendsRedemptionPremiumReversal_019ed6c3-a36f-7047-9ba9-7760f95becfd" xlink:href="nix-20260630.xsd#nix_PreferredDividendsRedemptionPremiumReversal"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic_019ed6c3-a36f-7f9c-a7d5-94b7ae8bed1f" xlink:to="loc_nix_PreferredDividendsRedemptionPremiumReversal_019ed6c3-a36f-7047-9ba9-7760f95becfd" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_019ed6c3-a36f-7d94-8f90-81ab8022038b" 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_ProfitLoss_019ed6c3-a36f-746f-9876-6120494803f6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProfitLoss"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetIncomeLoss_019ed6c3-a36f-7d94-8f90-81ab8022038b" xlink:to="loc_us-gaap_ProfitLoss_019ed6c3-a36f-746f-9876-6120494803f6" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossAttributableToNoncontrollingInterest_019ed6c3-a36f-72e4-a60f-8a66929cf49c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetIncomeLossAttributableToNoncontrollingInterest"/>
    <link:calculationArc order="2" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetIncomeLoss_019ed6c3-a36f-7d94-8f90-81ab8022038b" xlink:to="loc_us-gaap_NetIncomeLossAttributableToNoncontrollingInterest_019ed6c3-a36f-72e4-a60f-8a66929cf49c" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NonoperatingIncomeExpense_019ed6c3-a36f-7ff9-b4a7-0a0d17af5c92" 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_InterestExpenseNonoperating_019ed6c3-a36f-7db3-8169-463ed4256199" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestExpenseNonoperating"/>
    <link:calculationArc order="1" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NonoperatingIncomeExpense_019ed6c3-a36f-7ff9-b4a7-0a0d17af5c92" xlink:to="loc_us-gaap_InterestExpenseNonoperating_019ed6c3-a36f-7db3-8169-463ed4256199" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherNonoperatingIncomeExpense_019ed6c3-a36f-7483-9808-783a472f14b2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherNonoperatingIncomeExpense"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NonoperatingIncomeExpense_019ed6c3-a36f-7ff9-b4a7-0a0d17af5c92" xlink:to="loc_us-gaap_OtherNonoperatingIncomeExpense_019ed6c3-a36f-7483-9808-783a472f14b2" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic_019ed6c3-a36f-729b-ac6f-31bec117f477" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingIncomeLoss_019ed6c3-a36f-7580-a2c4-de62f3b0e239" 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_IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic_019ed6c3-a36f-729b-ac6f-31bec117f477" xlink:to="loc_us-gaap_OperatingIncomeLoss_019ed6c3-a36f-7580-a2c4-de62f3b0e239" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NonoperatingIncomeExpense_019ed6c3-a36f-7cb8-8dfe-1d5b87ba17db" 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_IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic_019ed6c3-a36f-729b-ac6f-31bec117f477" xlink:to="loc_us-gaap_NonoperatingIncomeExpense_019ed6c3-a36f-7cb8-8dfe-1d5b87ba17db" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RegulatedOperatingRevenue_019ed6c3-a36f-78e0-a886-d85665176e0e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RegulatedOperatingRevenue"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_019ed6c3-a36f-79c4-a5de-f292b332ccf7" 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_RegulatedOperatingRevenue_019ed6c3-a36f-78e0-a886-d85665176e0e" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_019ed6c3-a36f-79c4-a5de-f292b332ccf7" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RegulatedOperatingRevenueOther_019ed6c3-a36f-7b56-a3e2-3c8ebec170d6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RegulatedOperatingRevenueOther"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_RegulatedOperatingRevenue_019ed6c3-a36f-78e0-a886-d85665176e0e" xlink:to="loc_us-gaap_RegulatedOperatingRevenueOther_019ed6c3-a36f-7b56-a3e2-3c8ebec170d6" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProfitLoss_019ed6c3-a36f-7718-8bf5-471d5b0e8e26" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProfitLoss"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic_019ed6c3-a36f-7058-8f05-8c4ca7bd6f5b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_ProfitLoss_019ed6c3-a36f-7718-8bf5-471d5b0e8e26" xlink:to="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic_019ed6c3-a36f-7058-8f05-8c4ca7bd6f5b" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxExpenseBenefit_019ed6c3-a36f-7c95-a1c6-82bc50bc2d7b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeTaxExpenseBenefit"/>
    <link:calculationArc order="2" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_ProfitLoss_019ed6c3-a36f-7718-8bf5-471d5b0e8e26" xlink:to="loc_us-gaap_IncomeTaxExpenseBenefit_019ed6c3-a36f-7c95-a1c6-82bc50bc2d7b" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingIncomeLoss_019ed6c3-a36f-7f6d-a36c-6569be82f760" 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_RegulatedOperatingRevenue_019ed6c3-a36f-7247-b27a-5d80f9440cce" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RegulatedOperatingRevenue"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_OperatingIncomeLoss_019ed6c3-a36f-7f6d-a36c-6569be82f760" xlink:to="loc_us-gaap_RegulatedOperatingRevenue_019ed6c3-a36f-7247-b27a-5d80f9440cce" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingCostsAndExpenses_019ed6c3-a36f-7fbd-a94c-839b608d014a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingCostsAndExpenses"/>
    <link:calculationArc order="2" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_OperatingIncomeLoss_019ed6c3-a36f-7f6d-a36c-6569be82f760" xlink:to="loc_us-gaap_OperatingCostsAndExpenses_019ed6c3-a36f-7fbd-a94c-839b608d014a" xlink:type="arc"/>
  </link:calculationLink>
  <link:roleRef roleURI="http://www.nisource.com/role/StatementsofConsolidatedComprehensiveIncomeLoss" xlink:type="simple" xlink:href="nix-20260630.xsd#StatementsofConsolidatedComprehensiveIncomeLoss"/>
  <link:calculationLink xlink:role="http://www.nisource.com/role/StatementsofConsolidatedComprehensiveIncomeLoss" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest_019ed6c3-a36f-7a75-b36f-9f4a80851f60" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProfitLoss_019ed6c3-a36f-7e00-b618-b0b858e640e7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProfitLoss"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest_019ed6c3-a36f-7a75-b36f-9f4a80851f60" xlink:to="loc_us-gaap_ProfitLoss_019ed6c3-a36f-7e00-b618-b0b858e640e7" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_019ed6c3-a36f-7318-afe7-8dfca96be3b6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTax"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest_019ed6c3-a36f-7a75-b36f-9f4a80851f60" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_019ed6c3-a36f-7318-afe7-8dfca96be3b6" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_019ed6c3-a36f-7883-8973-8544fc680540" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTax"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax_019ed6c3-a36f-71ce-a50f-de4b097d36d6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_019ed6c3-a36f-7883-8973-8544fc680540" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax_019ed6c3-a36f-71ce-a50f-de4b097d36d6" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationAndTax_019ed6c3-a36f-7df0-a6b2-c8e908b4906b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationAndTax"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_019ed6c3-a36f-7883-8973-8544fc680540" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationAndTax_019ed6c3-a36f-7df0-a6b2-c8e908b4906b" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax_019ed6c3-a36f-70d5-bde6-6bbf469f28b7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax"/>
    <link:calculationArc order="3" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_019ed6c3-a36f-7883-8973-8544fc680540" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax_019ed6c3-a36f-70d5-bde6-6bbf469f28b7" xlink:type="arc"/>
  </link:calculationLink>
  <link:roleRef roleURI="http://www.nisource.com/role/StatementsofConsolidatedBalanceSheets" xlink:type="simple" xlink:href="nix-20260630.xsd#StatementsofConsolidatedBalanceSheets"/>
  <link:calculationLink xlink:role="http://www.nisource.com/role/StatementsofConsolidatedBalanceSheets" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PublicUtilitiesPropertyPlantAndEquipmentNet_019ed6c3-a370-7c9b-ac0f-1d7ddef19116" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PublicUtilitiesPropertyPlantAndEquipmentNet"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PublicUtilitiesPropertyPlantAndEquipmentPlantInService_019ed6c3-a370-7dbe-89d1-7cfd0c504563" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PublicUtilitiesPropertyPlantAndEquipmentPlantInService"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_PublicUtilitiesPropertyPlantAndEquipmentNet_019ed6c3-a370-7c9b-ac0f-1d7ddef19116" xlink:to="loc_us-gaap_PublicUtilitiesPropertyPlantAndEquipmentPlantInService_019ed6c3-a370-7dbe-89d1-7cfd0c504563" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PublicUtilitiesPropertyPlantAndEquipmentAccumulatedDepreciation_019ed6c3-a370-7dce-a138-fafcbd0a0080" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PublicUtilitiesPropertyPlantAndEquipmentAccumulatedDepreciation"/>
    <link:calculationArc order="2" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_PublicUtilitiesPropertyPlantAndEquipmentNet_019ed6c3-a370-7c9b-ac0f-1d7ddef19116" xlink:to="loc_us-gaap_PublicUtilitiesPropertyPlantAndEquipmentAccumulatedDepreciation_019ed6c3-a370-7dce-a138-fafcbd0a0080" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsReceivableNetCurrent_019ed6c3-a370-7312-bb83-9dcf89ffba86" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccountsReceivableNetCurrent"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsReceivableGrossCurrent_019ed6c3-a370-71e7-93d1-37aaf0e2cde6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccountsReceivableGrossCurrent"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_AccountsReceivableNetCurrent_019ed6c3-a370-7312-bb83-9dcf89ffba86" xlink:to="loc_us-gaap_AccountsReceivableGrossCurrent_019ed6c3-a370-71e7-93d1-37aaf0e2cde6" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllowanceForDoubtfulAccountsReceivableCurrent_019ed6c3-a370-765b-95cd-a9351ea9f75b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AllowanceForDoubtfulAccountsReceivableCurrent"/>
    <link:calculationArc order="2" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_AccountsReceivableNetCurrent_019ed6c3-a370-7312-bb83-9dcf89ffba86" xlink:to="loc_us-gaap_AllowanceForDoubtfulAccountsReceivableCurrent_019ed6c3-a370-765b-95cd-a9351ea9f75b" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsCurrent_019ed6c3-a370-7d24-8309-bd0c47ceb0fe" 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_CashAndCashEquivalentsAtCarryingValue_019ed6c3-a370-71a5-bda7-9f5249ba6c1d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_AssetsCurrent_019ed6c3-a370-7d24-8309-bd0c47ceb0fe" xlink:to="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_019ed6c3-a370-71a5-bda7-9f5249ba6c1d" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedCashAndCashEquivalents_019ed6c3-a370-78fc-949e-8cabab72f833" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RestrictedCashAndCashEquivalents"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_AssetsCurrent_019ed6c3-a370-7d24-8309-bd0c47ceb0fe" xlink:to="loc_us-gaap_RestrictedCashAndCashEquivalents_019ed6c3-a370-78fc-949e-8cabab72f833" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsReceivableNetCurrent_019ed6c3-a370-79d7-81da-b6f00f5bbb0c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccountsReceivableNetCurrent"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_AssetsCurrent_019ed6c3-a370-7d24-8309-bd0c47ceb0fe" xlink:to="loc_us-gaap_AccountsReceivableNetCurrent_019ed6c3-a370-79d7-81da-b6f00f5bbb0c" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EnergyRelatedInventoryNaturalGasInStorage_019ed6c3-a370-7339-ae85-6e5362235df0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EnergyRelatedInventoryNaturalGasInStorage"/>
    <link:calculationArc order="4" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_AssetsCurrent_019ed6c3-a370-7d24-8309-bd0c47ceb0fe" xlink:to="loc_us-gaap_EnergyRelatedInventoryNaturalGasInStorage_019ed6c3-a370-7339-ae85-6e5362235df0" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InventoryRawMaterialsAndSupplies_019ed6c3-a370-747c-996d-3a22d86492ff" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InventoryRawMaterialsAndSupplies"/>
    <link:calculationArc order="5" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_AssetsCurrent_019ed6c3-a370-7d24-8309-bd0c47ceb0fe" xlink:to="loc_us-gaap_InventoryRawMaterialsAndSupplies_019ed6c3-a370-747c-996d-3a22d86492ff" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EnergyRelatedInventoryCoal_019ed6c3-a370-7490-a59c-d64f35cbcc3c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EnergyRelatedInventoryCoal"/>
    <link:calculationArc order="6" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_AssetsCurrent_019ed6c3-a370-7d24-8309-bd0c47ceb0fe" xlink:to="loc_us-gaap_EnergyRelatedInventoryCoal_019ed6c3-a370-7490-a59c-d64f35cbcc3c" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_nix_ExchangeGasReceivable_019ed6c3-a370-795e-8768-2c101d6e6d71" xlink:href="nix-20260630.xsd#nix_ExchangeGasReceivable"/>
    <link:calculationArc order="7" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_AssetsCurrent_019ed6c3-a370-7d24-8309-bd0c47ceb0fe" xlink:to="loc_nix_ExchangeGasReceivable_019ed6c3-a370-795e-8768-2c101d6e6d71" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RegulatoryAssetsCurrent_019ed6c3-a370-796a-a1b5-022a5b6a6f38" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RegulatoryAssetsCurrent"/>
    <link:calculationArc order="8" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_AssetsCurrent_019ed6c3-a370-7d24-8309-bd0c47ceb0fe" xlink:to="loc_us-gaap_RegulatoryAssetsCurrent_019ed6c3-a370-796a-a1b5-022a5b6a6f38" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_nix_DepositsToRenewableGenerationAssetDeveloper_019ed6c3-a370-788b-92a9-8103ac253cfa" xlink:href="nix-20260630.xsd#nix_DepositsToRenewableGenerationAssetDeveloper"/>
    <link:calculationArc order="9" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_AssetsCurrent_019ed6c3-a370-7d24-8309-bd0c47ceb0fe" xlink:to="loc_nix_DepositsToRenewableGenerationAssetDeveloper_019ed6c3-a370-788b-92a9-8103ac253cfa" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherAssetsCurrent_019ed6c3-a370-7176-b8f2-c12b5bc7c198" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherAssetsCurrent"/>
    <link:calculationArc order="10" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_AssetsCurrent_019ed6c3-a370-7d24-8309-bd0c47ceb0fe" xlink:to="loc_us-gaap_OtherAssetsCurrent_019ed6c3-a370-7176-b8f2-c12b5bc7c198" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PrepaidExpenseCurrent_019ed6c3-a370-7681-a68f-3099a3e54f06" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PrepaidExpenseCurrent"/>
    <link:calculationArc order="11" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_AssetsCurrent_019ed6c3-a370-7d24-8309-bd0c47ceb0fe" xlink:to="loc_us-gaap_PrepaidExpenseCurrent_019ed6c3-a370-7681-a68f-3099a3e54f06" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxReceivable_019ed6c3-a370-7a3c-b67f-8d453455de59" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeTaxReceivable"/>
    <link:calculationArc order="12" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_AssetsCurrent_019ed6c3-a370-7d24-8309-bd0c47ceb0fe" xlink:to="loc_us-gaap_IncomeTaxReceivable_019ed6c3-a370-7a3c-b67f-8d453455de59" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentsAndOtherNoncurrentAssets_019ed6c3-a370-7cbc-8239-1aa562f2984e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InvestmentsAndOtherNoncurrentAssets"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtSecuritiesNoncurrent_019ed6c3-a370-754e-904c-13c7b6141bdd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AvailableForSaleSecuritiesDebtSecuritiesNoncurrent"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_InvestmentsAndOtherNoncurrentAssets_019ed6c3-a370-7cbc-8239-1aa562f2984e" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtSecuritiesNoncurrent_019ed6c3-a370-754e-904c-13c7b6141bdd" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures_019ed6c3-a370-711f-a624-515632492e33" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_InvestmentsAndOtherNoncurrentAssets_019ed6c3-a370-7cbc-8239-1aa562f2984e" xlink:to="loc_us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures_019ed6c3-a370-711f-a624-515632492e33" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherLongTermInvestments_019ed6c3-a370-7a55-80fe-b0888b53ec6a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherLongTermInvestments"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_InvestmentsAndOtherNoncurrentAssets_019ed6c3-a370-7cbc-8239-1aa562f2984e" xlink:to="loc_us-gaap_OtherLongTermInvestments_019ed6c3-a370-7a55-80fe-b0888b53ec6a" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Assets_019ed6c3-a370-71b5-9192-73ba1136f31d" 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_PublicUtilitiesPropertyPlantAndEquipmentNet_019ed6c3-a370-71bf-9d37-228cd08802d0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PublicUtilitiesPropertyPlantAndEquipmentNet"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_Assets_019ed6c3-a370-71b5-9192-73ba1136f31d" xlink:to="loc_us-gaap_PublicUtilitiesPropertyPlantAndEquipmentNet_019ed6c3-a370-71bf-9d37-228cd08802d0" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentsAndOtherNoncurrentAssets_019ed6c3-a370-7dc5-83e0-43dd8848a41e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InvestmentsAndOtherNoncurrentAssets"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_Assets_019ed6c3-a370-71b5-9192-73ba1136f31d" xlink:to="loc_us-gaap_InvestmentsAndOtherNoncurrentAssets_019ed6c3-a370-7dc5-83e0-43dd8848a41e" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsCurrent_019ed6c3-a370-79b7-b1bb-57a75464b991" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetsCurrent"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_Assets_019ed6c3-a370-71b5-9192-73ba1136f31d" xlink:to="loc_us-gaap_AssetsCurrent_019ed6c3-a370-79b7-b1bb-57a75464b991" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherAssetsNoncurrent_019ed6c3-a370-7122-bd1c-ab0c091af37f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherAssetsNoncurrent"/>
    <link:calculationArc order="4" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_Assets_019ed6c3-a370-71b5-9192-73ba1136f31d" xlink:to="loc_us-gaap_OtherAssetsNoncurrent_019ed6c3-a370-7122-bd1c-ab0c091af37f" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherAssets_019faa15-b0d6-7d3e-a7dc-1167feccf74c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherAssets"/>
    <link:calculationArc order="5" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_Assets_019ed6c3-a370-71b5-9192-73ba1136f31d" xlink:to="loc_us-gaap_OtherAssets_019faa15-b0d6-7d3e-a7dc-1167feccf74c" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesNoncurrent_019ed6c3-a370-778c-b47e-a8ff47642723" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LiabilitiesNoncurrent"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredIncomeTaxLiabilitiesNet_019ed6c3-a370-7720-958d-9b9d63fe43fe" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DeferredIncomeTaxLiabilitiesNet"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesNoncurrent_019ed6c3-a370-778c-b47e-a8ff47642723" xlink:to="loc_us-gaap_DeferredIncomeTaxLiabilitiesNet_019ed6c3-a370-7720-958d-9b9d63fe43fe" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PensionAndOtherPostretirementAndPostemploymentBenefitPlansLiabilitiesNoncurrent_019ed6c3-a370-7d89-bbd5-eccd7ee7794b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PensionAndOtherPostretirementAndPostemploymentBenefitPlansLiabilitiesNoncurrent"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesNoncurrent_019ed6c3-a370-778c-b47e-a8ff47642723" xlink:to="loc_us-gaap_PensionAndOtherPostretirementAndPostemploymentBenefitPlansLiabilitiesNoncurrent_019ed6c3-a370-7d89-bbd5-eccd7ee7794b" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RegulatoryLiabilityNoncurrent_019ed6c3-a370-7bf6-b666-c1b753cf0db1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RegulatoryLiabilityNoncurrent"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesNoncurrent_019ed6c3-a370-778c-b47e-a8ff47642723" xlink:to="loc_us-gaap_RegulatoryLiabilityNoncurrent_019ed6c3-a370-7bf6-b666-c1b753cf0db1" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetRetirementObligationsNoncurrent_019ed6c3-a370-7d1e-8719-1965d26ff6fe" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetRetirementObligationsNoncurrent"/>
    <link:calculationArc order="4" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesNoncurrent_019ed6c3-a370-778c-b47e-a8ff47642723" xlink:to="loc_us-gaap_AssetRetirementObligationsNoncurrent_019ed6c3-a370-7d1e-8719-1965d26ff6fe" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherLiabilitiesNoncurrent_019ed6c3-a370-7534-aad1-23edf41d6e5b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherLiabilitiesNoncurrent"/>
    <link:calculationArc order="5" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesNoncurrent_019ed6c3-a370-778c-b47e-a8ff47642723" xlink:to="loc_us-gaap_OtherLiabilitiesNoncurrent_019ed6c3-a370-7534-aad1-23edf41d6e5b" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccruedInsuranceNoncurrent_019ed6c3-a370-7909-a4ac-6b2182023da0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccruedInsuranceNoncurrent"/>
    <link:calculationArc order="6" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesNoncurrent_019ed6c3-a370-778c-b47e-a8ff47642723" xlink:to="loc_us-gaap_AccruedInsuranceNoncurrent_019ed6c3-a370-7909-a4ac-6b2182023da0" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CapitalizationLongtermDebtAndEquity_019ed6c3-a370-7c55-bdc9-a38ad6eeee5d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CapitalizationLongtermDebtAndEquity"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_019ed6c3-a370-70fd-8fe3-e600417bbc20" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_CapitalizationLongtermDebtAndEquity_019ed6c3-a370-7c55-bdc9-a38ad6eeee5d" xlink:to="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_019ed6c3-a370-70fd-8fe3-e600417bbc20" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtAndCapitalLeaseObligations_019ed6c3-a370-75d3-99b0-d8dcfb1c886b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongTermDebtAndCapitalLeaseObligations"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_CapitalizationLongtermDebtAndEquity_019ed6c3-a370-7c55-bdc9-a38ad6eeee5d" xlink:to="loc_us-gaap_LongTermDebtAndCapitalLeaseObligations_019ed6c3-a370-75d3-99b0-d8dcfb1c886b" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherAssetsNoncurrent_019ed6c3-a370-78c8-b0ae-dd7c6d4fb528" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherAssetsNoncurrent"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RegulatoryAssetsNoncurrent_019ed6c3-a370-77b0-b620-8fc411139cd0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RegulatoryAssetsNoncurrent"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_OtherAssetsNoncurrent_019ed6c3-a370-78c8-b0ae-dd7c6d4fb528" xlink:to="loc_us-gaap_RegulatoryAssetsNoncurrent_019ed6c3-a370-77b0-b620-8fc411139cd0" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Goodwill_019ed6c3-a370-7226-9915-860712287a81" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Goodwill"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_OtherAssetsNoncurrent_019ed6c3-a370-78c8-b0ae-dd7c6d4fb528" xlink:to="loc_us-gaap_Goodwill_019ed6c3-a370-7226-9915-860712287a81" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_nix_DeferredChargesAndOther_019ed6c3-a370-7908-83d1-0edc041731b9" xlink:href="nix-20260630.xsd#nix_DeferredChargesAndOther"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_OtherAssetsNoncurrent_019ed6c3-a370-78c8-b0ae-dd7c6d4fb528" xlink:to="loc_nix_DeferredChargesAndOther_019ed6c3-a370-7908-83d1-0edc041731b9" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_019ed6c3-a370-7035-b3c9-fd7711190384" 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_019ed6c3-a370-7c2f-bfc7-842beaf788e7" 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_019ed6c3-a370-7035-b3c9-fd7711190384" xlink:to="loc_us-gaap_CommonStockValue_019ed6c3-a370-7c2f-bfc7-842beaf788e7" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockValueOutstanding_019ed6c3-a370-7b11-80df-bb4e005c62b4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PreferredStockValueOutstanding"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_StockholdersEquity_019ed6c3-a370-7035-b3c9-fd7711190384" xlink:to="loc_us-gaap_PreferredStockValueOutstanding_019ed6c3-a370-7b11-80df-bb4e005c62b4" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockValue_019ed6c3-a370-7930-8cf2-95273d951b83" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TreasuryStockValue"/>
    <link:calculationArc order="3" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_StockholdersEquity_019ed6c3-a370-7035-b3c9-fd7711190384" xlink:to="loc_us-gaap_TreasuryStockValue_019ed6c3-a370-7930-8cf2-95273d951b83" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdditionalPaidInCapitalCommonStock_019ed6c3-a370-743a-99c3-41b9d20fe57c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AdditionalPaidInCapitalCommonStock"/>
    <link:calculationArc order="4" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_StockholdersEquity_019ed6c3-a370-7035-b3c9-fd7711190384" xlink:to="loc_us-gaap_AdditionalPaidInCapitalCommonStock_019ed6c3-a370-743a-99c3-41b9d20fe57c" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetainedEarningsAccumulatedDeficit_019ed6c3-a370-769a-a100-0d4678cb4276" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RetainedEarningsAccumulatedDeficit"/>
    <link:calculationArc order="5" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_StockholdersEquity_019ed6c3-a370-7035-b3c9-fd7711190384" xlink:to="loc_us-gaap_RetainedEarningsAccumulatedDeficit_019ed6c3-a370-769a-a100-0d4678cb4276" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_019ed6c3-a370-7e70-8cca-6b38b257b2ab" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax"/>
    <link:calculationArc order="6" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_StockholdersEquity_019ed6c3-a370-7035-b3c9-fd7711190384" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_019ed6c3-a370-7e70-8cca-6b38b257b2ab" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquity_019ed6c3-a370-7aeb-8dfa-4d16286be6cb" 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_CapitalizationLongtermDebtAndEquity_019ed6c3-a370-7830-a21d-2cc53116c806" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CapitalizationLongtermDebtAndEquity"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquity_019ed6c3-a370-7aeb-8dfa-4d16286be6cb" xlink:to="loc_us-gaap_CapitalizationLongtermDebtAndEquity_019ed6c3-a370-7830-a21d-2cc53116c806" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesCurrent_019ed6c3-a370-7fb2-a2de-735f0008e126" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LiabilitiesCurrent"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquity_019ed6c3-a370-7aeb-8dfa-4d16286be6cb" xlink:to="loc_us-gaap_LiabilitiesCurrent_019ed6c3-a370-7fb2-a2de-735f0008e126" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesNoncurrent_019ed6c3-a370-712b-8dc2-766007a0c6a7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LiabilitiesNoncurrent"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquity_019ed6c3-a370-7aeb-8dfa-4d16286be6cb" xlink:to="loc_us-gaap_LiabilitiesNoncurrent_019ed6c3-a370-712b-8dc2-766007a0c6a7" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesCurrent_019ed6c3-a370-70b2-8c51-7587bc96b245" 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_LongTermDebtAndCapitalLeaseObligationsCurrent_019ed6c3-a370-74c1-ae4d-16f7a5dcff52" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongTermDebtAndCapitalLeaseObligationsCurrent"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesCurrent_019ed6c3-a370-70b2-8c51-7587bc96b245" xlink:to="loc_us-gaap_LongTermDebtAndCapitalLeaseObligationsCurrent_019ed6c3-a370-74c1-ae4d-16f7a5dcff52" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermBorrowings_019ed6c3-a370-7616-8de1-e0d4c645f93c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShortTermBorrowings"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesCurrent_019ed6c3-a370-70b2-8c51-7587bc96b245" xlink:to="loc_us-gaap_ShortTermBorrowings_019ed6c3-a370-7616-8de1-e0d4c645f93c" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsPayableCurrent_019ed6c3-a370-7572-9cfa-e1a77ad67ab6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccountsPayableCurrent"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesCurrent_019ed6c3-a370-70b2-8c51-7587bc96b245" xlink:to="loc_us-gaap_AccountsPayableCurrent_019ed6c3-a370-7572-9cfa-e1a77ad67ab6" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_nix_CommonDividendsPayableCurrent_019ed6c3-a370-71d4-99bd-6616d6856af5" xlink:href="nix-20260630.xsd#nix_CommonDividendsPayableCurrent"/>
    <link:calculationArc order="4" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesCurrent_019ed6c3-a370-70b2-8c51-7587bc96b245" xlink:to="loc_nix_CommonDividendsPayableCurrent_019ed6c3-a370-71d4-99bd-6616d6856af5" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_nix_PreferredDividendsPayableCurrent_019ed6c3-a370-7602-82f6-e9145c9a8802" xlink:href="nix-20260630.xsd#nix_PreferredDividendsPayableCurrent"/>
    <link:calculationArc order="5" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesCurrent_019ed6c3-a370-70b2-8c51-7587bc96b245" xlink:to="loc_nix_PreferredDividendsPayableCurrent_019ed6c3-a370-7602-82f6-e9145c9a8802" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerLiabilityCurrent_019ed6c3-a370-762f-8c6c-4466ff954219" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ContractWithCustomerLiabilityCurrent"/>
    <link:calculationArc order="6" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesCurrent_019ed6c3-a370-70b2-8c51-7587bc96b245" xlink:to="loc_us-gaap_ContractWithCustomerLiabilityCurrent_019ed6c3-a370-762f-8c6c-4466ff954219" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TaxesPayableCurrent_019ed6c3-a370-7c3a-8fed-d6762ec8ba5f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TaxesPayableCurrent"/>
    <link:calculationArc order="7" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesCurrent_019ed6c3-a370-70b2-8c51-7587bc96b245" xlink:to="loc_us-gaap_TaxesPayableCurrent_019ed6c3-a370-7c3a-8fed-d6762ec8ba5f" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestPayableCurrent_019ed6c3-a370-73e4-a5ef-8fe894929d58" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestPayableCurrent"/>
    <link:calculationArc order="8" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesCurrent_019ed6c3-a370-70b2-8c51-7587bc96b245" xlink:to="loc_us-gaap_InterestPayableCurrent_019ed6c3-a370-73e4-a5ef-8fe894929d58" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_nix_ExchangeGasPayable_019ed6c3-a370-7385-9280-1a9727a0b71e" xlink:href="nix-20260630.xsd#nix_ExchangeGasPayable"/>
    <link:calculationArc order="9" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesCurrent_019ed6c3-a370-70b2-8c51-7587bc96b245" xlink:to="loc_nix_ExchangeGasPayable_019ed6c3-a370-7385-9280-1a9727a0b71e" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RegulatoryLiabilityCurrent_019ed6c3-a370-759d-9a40-aad72a425d16" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RegulatoryLiabilityCurrent"/>
    <link:calculationArc order="10" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesCurrent_019ed6c3-a370-70b2-8c51-7587bc96b245" xlink:to="loc_us-gaap_RegulatoryLiabilityCurrent_019ed6c3-a370-759d-9a40-aad72a425d16" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeRelatedLiabilitiesCurrent_019ed6c3-a370-7dbf-979f-eff92a5ac225" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EmployeeRelatedLiabilitiesCurrent"/>
    <link:calculationArc order="11" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesCurrent_019ed6c3-a370-70b2-8c51-7587bc96b245" xlink:to="loc_us-gaap_EmployeeRelatedLiabilitiesCurrent_019ed6c3-a370-7dbf-979f-eff92a5ac225" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherLiabilitiesCurrent_019ed6c3-a370-7db9-9a41-409cf909181d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherLiabilitiesCurrent"/>
    <link:calculationArc order="12" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesCurrent_019ed6c3-a370-70b2-8c51-7587bc96b245" xlink:to="loc_us-gaap_OtherLiabilitiesCurrent_019ed6c3-a370-7db9-9a41-409cf909181d" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_nix_ObligationsToRenewableGenerationAssetDeveloper_019ed6c3-a370-752b-bbc0-90ff33190b75" xlink:href="nix-20260630.xsd#nix_ObligationsToRenewableGenerationAssetDeveloper"/>
    <link:calculationArc order="13" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesCurrent_019ed6c3-a370-70b2-8c51-7587bc96b245" xlink:to="loc_nix_ObligationsToRenewableGenerationAssetDeveloper_019ed6c3-a370-752b-bbc0-90ff33190b75" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetRetirementObligation_019ed6c3-a370-7541-bd0b-b05d8662658e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetRetirementObligation"/>
    <link:calculationArc order="14" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesCurrent_019ed6c3-a370-70b2-8c51-7587bc96b245" xlink:to="loc_us-gaap_AssetRetirementObligation_019ed6c3-a370-7541-bd0b-b05d8662658e" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_019ed6c3-a370-7bc9-b6e3-c0b40592385c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_019ed6c3-a370-7b07-b586-e393aa86bf61" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockholdersEquity"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_019ed6c3-a370-7bc9-b6e3-c0b40592385c" xlink:to="loc_us-gaap_StockholdersEquity_019ed6c3-a370-7b07-b586-e393aa86bf61" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MinorityInterest_019ed6c3-a370-7700-8bb7-48e2e24d43e6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_MinorityInterest"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_019ed6c3-a370-7bc9-b6e3-c0b40592385c" xlink:to="loc_us-gaap_MinorityInterest_019ed6c3-a370-7700-8bb7-48e2e24d43e6" xlink:type="arc"/>
  </link:calculationLink>
  <link:roleRef roleURI="http://www.nisource.com/role/StatementsofConsolidatedCashFlows" xlink:type="simple" xlink:href="nix-20260630.xsd#StatementsofConsolidatedCashFlows"/>
  <link:calculationLink xlink:role="http://www.nisource.com/role/StatementsofConsolidatedCashFlows" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_019ed6c3-a370-7542-8ea0-6720aac9d443" 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_PaymentsToAcquirePropertyPlantAndEquipment_019ed6c3-a370-7fb2-972a-b6f57793ea47" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PaymentsToAcquirePropertyPlantAndEquipment"/>
    <link:calculationArc order="1" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_019ed6c3-a370-7542-8ea0-6720aac9d443" xlink:to="loc_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_019ed6c3-a370-7fb2-972a-b6f57793ea47" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsToAcquireAvailableForSaleSecuritiesDebt_019ed6c3-a370-723c-8827-ee587b7cb664" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PaymentsToAcquireAvailableForSaleSecuritiesDebt"/>
    <link:calculationArc order="2" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_019ed6c3-a370-7542-8ea0-6720aac9d443" xlink:to="loc_us-gaap_PaymentsToAcquireAvailableForSaleSecuritiesDebt_019ed6c3-a370-723c-8827-ee587b7cb664" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromSaleOfAvailableForSaleSecuritiesDebt_019ed6c3-a370-75ee-9c6d-95ff1430edbf" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProceedsFromSaleOfAvailableForSaleSecuritiesDebt"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_019ed6c3-a370-7542-8ea0-6720aac9d443" xlink:to="loc_us-gaap_ProceedsFromSaleOfAvailableForSaleSecuritiesDebt_019ed6c3-a370-75ee-9c6d-95ff1430edbf" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_nix_PaymentToRenewableGenerationAssetDeveloper_019ed6c3-a370-7ad0-a159-93a7775b960e" xlink:href="nix-20260630.xsd#nix_PaymentToRenewableGenerationAssetDeveloper"/>
    <link:calculationArc order="4" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_019ed6c3-a370-7542-8ea0-6720aac9d443" xlink:to="loc_nix_PaymentToRenewableGenerationAssetDeveloper_019ed6c3-a370-7ad0-a159-93a7775b960e" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_nix_PaymentsForAdvancedDepositsForProjectCosts_019ed6c3-a370-7cd3-b81c-5270fc5bd43d" xlink:href="nix-20260630.xsd#nix_PaymentsForAdvancedDepositsForProjectCosts"/>
    <link:calculationArc order="5" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_019ed6c3-a370-7542-8ea0-6720aac9d443" xlink:to="loc_nix_PaymentsForAdvancedDepositsForProjectCosts_019ed6c3-a370-7cd3-b81c-5270fc5bd43d" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsForProceedsFromOtherInvestingActivities_019ed6c3-a370-76af-a59d-0f2444eaac33" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PaymentsForProceedsFromOtherInvestingActivities"/>
    <link:calculationArc order="6" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_019ed6c3-a370-7542-8ea0-6720aac9d443" xlink:to="loc_us-gaap_PaymentsForProceedsFromOtherInvestingActivities_019ed6c3-a370-76af-a59d-0f2444eaac33" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsForRemovalCosts_019ed6c3-a370-7c0d-a568-253c31b582f8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PaymentsForRemovalCosts"/>
    <link:calculationArc order="7" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_019ed6c3-a370-7542-8ea0-6720aac9d443" xlink:to="loc_us-gaap_PaymentsForRemovalCosts_019ed6c3-a370-7c0d-a568-253c31b582f8" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_019faa14-c95d-7064-bade-b5465cb25383" 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_ProceedsFromIssuanceOfLongTermDebt_019faa14-c95d-7563-890e-c625c0c31049" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProceedsFromIssuanceOfLongTermDebt"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_019faa14-c95d-7064-bade-b5465cb25383" xlink:to="loc_us-gaap_ProceedsFromIssuanceOfLongTermDebt_019faa14-c95d-7563-890e-c625c0c31049" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeasePrincipalPayments_019faa14-c95d-7d5f-a7a8-47ce1e6b6632" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinanceLeasePrincipalPayments"/>
    <link:calculationArc order="2" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_019faa14-c95d-7064-bade-b5465cb25383" xlink:to="loc_us-gaap_FinanceLeasePrincipalPayments_019faa14-c95d-7d5f-a7a8-47ce1e6b6632" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromRepaymentsOfShortTermDebtMaturingInThreeMonthsOrLess_019faa14-c95d-7548-ada7-46e09b723aed" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProceedsFromRepaymentsOfShortTermDebtMaturingInThreeMonthsOrLess"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_019faa14-c95d-7064-bade-b5465cb25383" xlink:to="loc_us-gaap_ProceedsFromRepaymentsOfShortTermDebtMaturingInThreeMonthsOrLess_019faa14-c95d-7548-ada7-46e09b723aed" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromIssuanceOfCommonStock_019faa14-c95d-7d2a-9b58-a08bff4ecdf3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProceedsFromIssuanceOfCommonStock"/>
    <link:calculationArc order="4" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_019faa14-c95d-7064-bade-b5465cb25383" xlink:to="loc_us-gaap_ProceedsFromIssuanceOfCommonStock_019faa14-c95d-7d2a-9b58-a08bff4ecdf3" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentOfFinancingAndStockIssuanceCosts_019faa14-c95d-7011-b5b8-b100fc4385fb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PaymentOfFinancingAndStockIssuanceCosts"/>
    <link:calculationArc order="5" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_019faa14-c95d-7064-bade-b5465cb25383" xlink:to="loc_us-gaap_PaymentOfFinancingAndStockIssuanceCosts_019faa14-c95d-7011-b5b8-b100fc4385fb" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromMinorityShareholders_019faa14-c95d-76b4-b02d-84ffc6d9586d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProceedsFromMinorityShareholders"/>
    <link:calculationArc order="6" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_019faa14-c95d-7064-bade-b5465cb25383" xlink:to="loc_us-gaap_ProceedsFromMinorityShareholders_019faa14-c95d-76b4-b02d-84ffc6d9586d" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsToMinorityShareholders_019faa14-c95d-7b60-88c7-66707f4a86fb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PaymentsToMinorityShareholders"/>
    <link:calculationArc order="7" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_019faa14-c95d-7064-bade-b5465cb25383" xlink:to="loc_us-gaap_PaymentsToMinorityShareholders_019faa14-c95d-7b60-88c7-66707f4a86fb" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_nix_DistributionsToTaxEquityPartners_019faa14-c95d-712c-a404-aec2041c345f" xlink:href="nix-20260630.xsd#nix_DistributionsToTaxEquityPartners"/>
    <link:calculationArc order="8" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_019faa14-c95d-7064-bade-b5465cb25383" xlink:to="loc_nix_DistributionsToTaxEquityPartners_019faa14-c95d-712c-a404-aec2041c345f" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsOfDividendsCommonStock_019faa14-c95d-7eff-a5e1-d4f6a61ac497" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PaymentsOfDividendsCommonStock"/>
    <link:calculationArc order="9" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_019faa14-c95d-7064-bade-b5465cb25383" xlink:to="loc_us-gaap_PaymentsOfDividendsCommonStock_019faa14-c95d-7eff-a5e1-d4f6a61ac497" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffect_019ed6c3-a370-791d-b590-0e575d84a274" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffect"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_019ed6c3-a370-7deb-9225-a37f5ee2c6c6" 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_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffect_019ed6c3-a370-791d-b590-0e575d84a274" xlink:to="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_019ed6c3-a370-7deb-9225-a37f5ee2c6c6" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_019ed6c3-a370-7a83-98e2-10acb270cc55" 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_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffect_019ed6c3-a370-791d-b590-0e575d84a274" xlink:to="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_019ed6c3-a370-7a83-98e2-10acb270cc55" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_019ed6c3-a370-76cf-878b-105d9cfc4f30" 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_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffect_019ed6c3-a370-791d-b590-0e575d84a274" xlink:to="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_019ed6c3-a370-76cf-878b-105d9cfc4f30" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_019ed6c3-a370-7f1b-bcec-7f2c89a70cc6" 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_ProfitLoss_019ed6c3-a370-755f-b356-606feed9a14d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProfitLoss"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_019ed6c3-a370-7f1b-bcec-7f2c89a70cc6" xlink:to="loc_us-gaap_ProfitLoss_019ed6c3-a370-755f-b356-606feed9a14d" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DepreciationDepletionAndAmortization_019ed6c3-a370-76a2-b98b-c55f1fc840ce" 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_019ed6c3-a370-7f1b-bcec-7f2c89a70cc6" xlink:to="loc_us-gaap_DepreciationDepletionAndAmortization_019ed6c3-a370-76a2-b98b-c55f1fc840ce" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredIncomeTaxesAndTaxCredits_019ed6c3-a370-7b70-b941-f8142e4040c4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DeferredIncomeTaxesAndTaxCredits"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_019ed6c3-a370-7f1b-bcec-7f2c89a70cc6" xlink:to="loc_us-gaap_DeferredIncomeTaxesAndTaxCredits_019ed6c3-a370-7b70-b941-f8142e4040c4" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainLossOnSaleOfOtherAssets_019ed6c3-a370-7e75-8a5c-a9d2cc63c2a1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_GainLossOnSaleOfOtherAssets"/>
    <link:calculationArc order="4" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_019ed6c3-a370-7f1b-bcec-7f2c89a70cc6" xlink:to="loc_us-gaap_GainLossOnSaleOfOtherAssets_019ed6c3-a370-7e75-8a5c-a9d2cc63c2a1" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetRetirementObligationCashPaidToSettle_019ed6c3-a370-7b80-90e4-27d3115e1491" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetRetirementObligationCashPaidToSettle"/>
    <link:calculationArc order="5" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_019ed6c3-a370-7f1b-bcec-7f2c89a70cc6" xlink:to="loc_us-gaap_AssetRetirementObligationCashPaidToSettle_019ed6c3-a370-7b80-90e4-27d3115e1491" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherOperatingActivitiesCashFlowStatement_019ed6c3-a370-75fc-b3e6-2a7f2a2b2c8b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherOperatingActivitiesCashFlowStatement"/>
    <link:calculationArc order="6" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_019ed6c3-a370-7f1b-bcec-7f2c89a70cc6" xlink:to="loc_us-gaap_OtherOperatingActivitiesCashFlowStatement_019ed6c3-a370-75fc-b3e6-2a7f2a2b2c8b" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInOtherOperatingCapitalNet_019ed6c3-a370-7f3a-81c1-fc60ab06f062" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncreaseDecreaseInOtherOperatingCapitalNet"/>
    <link:calculationArc order="7" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_019ed6c3-a370-7f1b-bcec-7f2c89a70cc6" xlink:to="loc_us-gaap_IncreaseDecreaseInOtherOperatingCapitalNet_019ed6c3-a370-7f3a-81c1-fc60ab06f062" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInRegulatoryAssetsAndLiabilities_019ed6c3-a370-7fec-8aad-0e700f86fda4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncreaseDecreaseInRegulatoryAssetsAndLiabilities"/>
    <link:calculationArc order="8" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_019ed6c3-a370-7f1b-bcec-7f2c89a70cc6" xlink:to="loc_us-gaap_IncreaseDecreaseInRegulatoryAssetsAndLiabilities_019ed6c3-a370-7fec-8aad-0e700f86fda4" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_nix_IncreaseDecreaseInDeferredChargesAndOtherNonCurrentAssets_019ed6c3-a370-76d4-ae5f-446d05f67aac" xlink:href="nix-20260630.xsd#nix_IncreaseDecreaseInDeferredChargesAndOtherNonCurrentAssets"/>
    <link:calculationArc order="9" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_019ed6c3-a370-7f1b-bcec-7f2c89a70cc6" xlink:to="loc_nix_IncreaseDecreaseInDeferredChargesAndOtherNonCurrentAssets_019ed6c3-a370-76d4-ae5f-446d05f67aac" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInOtherNoncurrentLiabilities_019ed6c3-a370-7a94-870f-56f1e94e2c82" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncreaseDecreaseInOtherNoncurrentLiabilities"/>
    <link:calculationArc order="10" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_019ed6c3-a370-7f1b-bcec-7f2c89a70cc6" xlink:to="loc_us-gaap_IncreaseDecreaseInOtherNoncurrentLiabilities_019ed6c3-a370-7a94-870f-56f1e94e2c82" xlink:type="arc"/>
  </link:calculationLink>
  <link:roleRef roleURI="http://www.nisource.com/role/EarningsPerShareScheduleofEarningsPerShareBasicandDilutedDetails" xlink:type="simple" xlink:href="nix-20260630.xsd#EarningsPerShareScheduleofEarningsPerShareBasicandDilutedDetails"/>
  <link:calculationLink xlink:role="http://www.nisource.com/role/EarningsPerShareScheduleofEarningsPerShareBasicandDilutedDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_019ed6c3-a370-7e38-91bd-79bc4059003e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncrementalCommonSharesAttributableToEquityForwardAgreements_019ed6c3-a370-7044-bd97-76b3ba4f5829" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncrementalCommonSharesAttributableToEquityForwardAgreements"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_019ed6c3-a370-7e38-91bd-79bc4059003e" xlink:to="loc_us-gaap_IncrementalCommonSharesAttributableToEquityForwardAgreements_019ed6c3-a370-7044-bd97-76b3ba4f5829" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_nix_IncrementalCommonSharesAttributableToDilutiveEffectOfEquityUnitPurchaseContractPaymentBalance_019ed6c3-a370-7ee0-845f-affe20f7a332" xlink:href="nix-20260630.xsd#nix_IncrementalCommonSharesAttributableToDilutiveEffectOfEquityUnitPurchaseContractPaymentBalance"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_019ed6c3-a370-7e38-91bd-79bc4059003e" xlink:to="loc_nix_IncrementalCommonSharesAttributableToDilutiveEffectOfEquityUnitPurchaseContractPaymentBalance_019ed6c3-a370-7ee0-845f-affe20f7a332" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncrementalCommonSharesAttributableToShareBasedPaymentArrangements_019ed6c3-a370-77c7-8691-f17648ae711e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncrementalCommonSharesAttributableToShareBasedPaymentArrangements"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_019ed6c3-a370-7e38-91bd-79bc4059003e" xlink:to="loc_us-gaap_IncrementalCommonSharesAttributableToShareBasedPaymentArrangements_019ed6c3-a370-77c7-8691-f17648ae711e" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_019ed6c3-a370-7611-a5fa-69ce8826ec25" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_WeightedAverageNumberOfSharesOutstandingBasic"/>
    <link:calculationArc order="4" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_019ed6c3-a370-7e38-91bd-79bc4059003e" xlink:to="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_019ed6c3-a370-7611-a5fa-69ce8826ec25" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_nix_IncrementalCommonSharesAttributableToDilutiveEffectOfEquityUnitPurchaseAgreementsIfConverted_019ed6c3-a370-7029-b9e6-b3ab26cc0e76" xlink:href="nix-20260630.xsd#nix_IncrementalCommonSharesAttributableToDilutiveEffectOfEquityUnitPurchaseAgreementsIfConverted"/>
    <link:calculationArc order="5" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_019ed6c3-a370-7e38-91bd-79bc4059003e" xlink:to="loc_nix_IncrementalCommonSharesAttributableToDilutiveEffectOfEquityUnitPurchaseAgreementsIfConverted_019ed6c3-a370-7029-b9e6-b3ab26cc0e76" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncrementalCommonSharesAttributableToContingentlyIssuableShares_019ed6c3-a370-7f08-be7f-dcd7917d9a8e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncrementalCommonSharesAttributableToContingentlyIssuableShares"/>
    <link:calculationArc order="6" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_019ed6c3-a370-7e38-91bd-79bc4059003e" xlink:to="loc_us-gaap_IncrementalCommonSharesAttributableToContingentlyIssuableShares_019ed6c3-a370-7f08-be7f-dcd7917d9a8e" xlink:type="arc"/>
  </link:calculationLink>
  <link:roleRef roleURI="http://www.nisource.com/role/PensionAndOtherPostretirementBenefitsComponentsOfThePlansNetPeriodicBenefitsCostDetails" xlink:type="simple" xlink:href="nix-20260630.xsd#PensionAndOtherPostretirementBenefitsComponentsOfThePlansNetPeriodicBenefitsCostDetails"/>
  <link:calculationLink xlink:role="http://www.nisource.com/role/PensionAndOtherPostretirementBenefitsComponentsOfThePlansNetPeriodicBenefitsCostDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost_019ed6c3-a42e-758a-8134-d0eb37af5712" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanServiceCost_019ed6c3-a42e-707f-a642-6b855f4de05d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DefinedBenefitPlanServiceCost"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost_019ed6c3-a42e-758a-8134-d0eb37af5712" xlink:to="loc_us-gaap_DefinedBenefitPlanServiceCost_019ed6c3-a42e-707f-a642-6b855f4de05d" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanAmortizationOfGainsLosses_019ed6c3-a42e-73c4-91e0-2e90e8fafb55" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DefinedBenefitPlanAmortizationOfGainsLosses"/>
    <link:calculationArc order="2" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost_019ed6c3-a42e-758a-8134-d0eb37af5712" xlink:to="loc_us-gaap_DefinedBenefitPlanAmortizationOfGainsLosses_019ed6c3-a42e-73c4-91e0-2e90e8fafb55" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets_019ed6c3-a42e-771d-bcf1-1ea4b082993b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets"/>
    <link:calculationArc order="3" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost_019ed6c3-a42e-758a-8134-d0eb37af5712" xlink:to="loc_us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets_019ed6c3-a42e-771d-bcf1-1ea4b082993b" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanAmortizationOfPriorServiceCostCredit_019ed6c3-a42e-7434-86bc-b2c29ec75c57" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DefinedBenefitPlanAmortizationOfPriorServiceCostCredit"/>
    <link:calculationArc order="4" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost_019ed6c3-a42e-758a-8134-d0eb37af5712" xlink:to="loc_us-gaap_DefinedBenefitPlanAmortizationOfPriorServiceCostCredit_019ed6c3-a42e-7434-86bc-b2c29ec75c57" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanInterestCost_019ed6c3-a42e-719f-8bb5-add6c5d9d092" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DefinedBenefitPlanInterestCost"/>
    <link:calculationArc order="5" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost_019ed6c3-a42e-758a-8134-d0eb37af5712" xlink:to="loc_us-gaap_DefinedBenefitPlanInterestCost_019ed6c3-a42e-719f-8bb5-add6c5d9d092" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanRecognizedNetGainLossDueToSettlements1_019ed6c3-a42e-7600-bc1e-73db0d3c036b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DefinedBenefitPlanRecognizedNetGainLossDueToSettlements1"/>
    <link:calculationArc order="6" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost_019ed6c3-a42e-758a-8134-d0eb37af5712" xlink:to="loc_us-gaap_DefinedBenefitPlanRecognizedNetGainLossDueToSettlements1_019ed6c3-a42e-7600-bc1e-73db0d3c036b" xlink:type="arc"/>
  </link:calculationLink>
</link:linkbase>
