<?xml version="1.0" encoding="US-ASCII"?>
<!--XBRL Document Created with Wdesk from Workiva-->
<!-- -->
<xsd:schema attributeFormDefault="unqualified" elementFormDefault="qualified" targetNamespace="http://www.allete.com/20200331" xmlns:ale="http://www.allete.com/20200331" xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:nonnum="http://www.xbrl.org/dtr/type/non-numeric" xmlns:num="http://www.xbrl.org/dtr/type/numeric" xmlns:us-types="http://fasb.org/us-types/2019-01-31" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" xmlns:xbrli="http://www.xbrl.org/2003/instance" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
  <xsd:import namespace="http://fasb.org/srt-types/2019-01-31" schemaLocation="http://xbrl.fasb.org/srt/2019/elts/srt-types-2019-01-31.xsd" />
  <xsd:import namespace="http://fasb.org/srt/2019-01-31" schemaLocation="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd" />
  <xsd:import namespace="http://fasb.org/us-gaap/2019-01-31" schemaLocation="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd" />
  <xsd:import namespace="http://fasb.org/us-roles/2019-01-31" schemaLocation="http://xbrl.fasb.org/us-gaap/2019/elts/us-roles-2019-01-31.xsd" />
  <xsd:import namespace="http://fasb.org/us-types/2019-01-31" schemaLocation="http://xbrl.fasb.org/us-gaap/2019/elts/us-types-2019-01-31.xsd" />
  <xsd:import namespace="http://www.xbrl.org/2003/instance" schemaLocation="http://www.xbrl.org/2003/xbrl-instance-2003-12-31.xsd" />
  <xsd:import namespace="http://www.xbrl.org/2003/linkbase" schemaLocation="http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd" />
  <xsd:import namespace="http://www.xbrl.org/2009/arcrole/fact-explanatoryFact" schemaLocation="http://www.xbrl.org/lrr/arcrole/factExplanatory-2009-12-16.xsd" />
  <xsd:import namespace="http://www.xbrl.org/2009/role/negated" schemaLocation="http://www.xbrl.org/lrr/role/negated-2009-12-16.xsd" />
  <xsd:import namespace="http://www.xbrl.org/2009/role/net" schemaLocation="http://www.xbrl.org/lrr/role/net-2009-12-16.xsd" />
  <xsd:import namespace="http://www.xbrl.org/dtr/type/non-numeric" schemaLocation="http://www.xbrl.org/dtr/type/nonNumeric-2009-12-16.xsd" />
  <xsd:import namespace="http://www.xbrl.org/dtr/type/numeric" schemaLocation="http://www.xbrl.org/dtr/type/numeric-2009-12-16.xsd" />
  <xsd:import namespace="http://xbrl.org/2005/xbrldt" schemaLocation="http://www.xbrl.org/2005/xbrldt-2005.xsd" />
  <xsd:import namespace="http://xbrl.sec.gov/country/2017-01-31" schemaLocation="https://xbrl.sec.gov/country/2017/country-2017-01-31.xsd" />
  <xsd:import namespace="http://xbrl.sec.gov/currency/2019-01-31" schemaLocation="https://xbrl.sec.gov/currency/2019/currency-2019-01-31.xsd" />
  <xsd:import namespace="http://xbrl.sec.gov/dei/2019-01-31" schemaLocation="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd" />
  <xsd:import namespace="http://xbrl.sec.gov/exch/2019-01-31" schemaLocation="https://xbrl.sec.gov/exch/2019/exch-2019-01-31.xsd" />
  <xsd:import namespace="http://xbrl.sec.gov/naics/2017-01-31" schemaLocation="http://xbrl.sec.gov/naics/2017/naics-2017-01-31.xsd" />
  <xsd:import namespace="http://xbrl.sec.gov/sic/2011-01-31" schemaLocation="http://xbrl.sec.gov/sic/2011/sic-2011-01-31.xsd" />
  <xsd:import namespace="http://xbrl.sec.gov/stpr/2018-01-31" schemaLocation="https://xbrl.sec.gov/stpr/2018/stpr-2018-01-31.xsd" />
  <xsd:annotation>
    <xsd:appinfo>
      <link:linkbaseRef xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:href="ale-20200331_cal.xml" xlink:role="http://www.xbrl.org/2003/role/calculationLinkbaseRef" xlink:type="simple" />
      <link:linkbaseRef xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:href="ale-20200331_def.xml" xlink:role="http://www.xbrl.org/2003/role/definitionLinkbaseRef" xlink:type="simple" />
      <link:linkbaseRef xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:href="ale-20200331_lab.xml" xlink:role="http://www.xbrl.org/2003/role/labelLinkbaseRef" xlink:type="simple" />
      <link:linkbaseRef xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:href="ale-20200331_pre.xml" xlink:role="http://www.xbrl.org/2003/role/presentationLinkbaseRef" xlink:type="simple" />
      <link:roleType id="BusinessSegments" roleURI="http://www.allete.com/role/BusinessSegments">
        <link:definition>2120100 - Disclosure - Business Segments</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="BusinessSegmentsDetails" roleURI="http://www.allete.com/role/BusinessSegmentsDetails">
        <link:definition>2420402 - Disclosure - Business Segments (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="BusinessSegmentsTables" roleURI="http://www.allete.com/role/BusinessSegmentsTables">
        <link:definition>2320301 - Disclosure - Business Segments (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="CommitmentsGuaranteesAndContingencies" roleURI="http://www.allete.com/role/CommitmentsGuaranteesAndContingencies">
        <link:definition>2114100 - Disclosure - Commitments, Guarantees and Contingencies</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="CommitmentsGuaranteesAndContingenciesCoalRailAndShippingContractsDetails" roleURI="http://www.allete.com/role/CommitmentsGuaranteesAndContingenciesCoalRailAndShippingContractsDetails">
        <link:definition>2414402 - Disclosure - Commitments, Guarantees and Contingencies - Coal, Rail and Shipping Contracts (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="CommitmentsGuaranteesAndContingenciesEnvironmentalMattersDetails" roleURI="http://www.allete.com/role/CommitmentsGuaranteesAndContingenciesEnvironmentalMattersDetails">
        <link:definition>2414404 - Disclosure - Commitments, Guarantees and Contingencies - Environmental Matters (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="CommitmentsGuaranteesAndContingenciesOtherMattersDetails" roleURI="http://www.allete.com/role/CommitmentsGuaranteesAndContingenciesOtherMattersDetails">
        <link:definition>2414405 - Disclosure - Commitments, Guarantees and Contingencies - Other Matters (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="CommitmentsGuaranteesAndContingenciesPowerPurchaseAgreementsDetails" roleURI="http://www.allete.com/role/CommitmentsGuaranteesAndContingenciesPowerPurchaseAgreementsDetails">
        <link:definition>2414401 - Disclosure - Commitments, Guarantees and Contingencies - Power Purchase Agreements (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="CommitmentsGuaranteesAndContingenciesTransmissionDetails" roleURI="http://www.allete.com/role/CommitmentsGuaranteesAndContingenciesTransmissionDetails">
        <link:definition>2414403 - Disclosure - Commitments, Guarantees and Contingencies - Transmission (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="ConsolidatedBalanceSheet" roleURI="http://www.allete.com/role/ConsolidatedBalanceSheet">
        <link:definition>1001000 - Statement - Consolidated Balance Sheet</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="ConsolidatedBalanceSheetParentheticals" roleURI="http://www.allete.com/role/ConsolidatedBalanceSheetParentheticals">
        <link:definition>1001001 - Statement - Consolidated Balance Sheet Parentheticals</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="ConsolidatedStatementOfCashFlows" roleURI="http://www.allete.com/role/ConsolidatedStatementOfCashFlows">
        <link:definition>1006000 - Statement - Consolidated Statement of Cash Flows</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="ConsolidatedStatementOfComprehensiveIncome" roleURI="http://www.allete.com/role/ConsolidatedStatementOfComprehensiveIncome">
        <link:definition>1004000 - Statement - Consolidated Statement of Comprehensive Income</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="ConsolidatedStatementOfComprehensiveIncomeCalc2" roleURI="http://www.allete.com/role/ConsolidatedStatementOfComprehensiveIncomeCalc2">
        <link:definition>1004000 - Statement - Consolidated Statement of Comprehensive Income</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="ConsolidatedStatementOfComprehensiveIncomeParentheticals" roleURI="http://www.allete.com/role/ConsolidatedStatementOfComprehensiveIncomeParentheticals">
        <link:definition>1004001 - Statement - Consolidated Statement of Comprehensive Income Parentheticals</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="ConsolidatedStatementOfIncome" roleURI="http://www.allete.com/role/ConsolidatedStatementOfIncome">
        <link:definition>1003000 - Statement - Consolidated Statement of Income</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="ConsolidatedStatementOfShareholdersEquity" roleURI="http://www.allete.com/role/ConsolidatedStatementOfShareholdersEquity">
        <link:definition>1007000 - Statement - Consolidated Statement of Shareholders' Equity</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="DocumentAndEntityInformationDocument" roleURI="http://www.allete.com/role/DocumentAndEntityInformationDocument">
        <link:definition>0001000 - Document - Document and Entity Information Document</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="EarningsPerShareAndCommonStock" roleURI="http://www.allete.com/role/EarningsPerShareAndCommonStock">
        <link:definition>2117100 - Disclosure - Earnings Per Share and Common Stock</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="EarningsPerShareAndCommonStockDetails" roleURI="http://www.allete.com/role/EarningsPerShareAndCommonStockDetails">
        <link:definition>2417402 - Disclosure - Earnings Per Share and Common Stock (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="EarningsPerShareAndCommonStockTables" roleURI="http://www.allete.com/role/EarningsPerShareAndCommonStockTables">
        <link:definition>2317301 - Disclosure - Earnings Per Share and Common Stock (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="EquityInvestments" roleURI="http://www.allete.com/role/EquityInvestments">
        <link:definition>2106100 - Disclosure - Equity Investments</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="EquityInvestmentsInvestmentInAtcDetails" roleURI="http://www.allete.com/role/EquityInvestmentsInvestmentInAtcDetails">
        <link:definition>2406402 - Disclosure - Equity Investments - Investment in ATC (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="EquityInvestmentsInvestmentInNobles2Details" roleURI="http://www.allete.com/role/EquityInvestmentsInvestmentInNobles2Details">
        <link:definition>2406403 - Disclosure - Equity Investments - Investment in Nobles 2 (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="EquityInvestmentsTables" roleURI="http://www.allete.com/role/EquityInvestmentsTables">
        <link:definition>2306301 - Disclosure - Equity Investments (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="FairValue" roleURI="http://www.allete.com/role/FairValue">
        <link:definition>2111100 - Disclosure - Fair Value</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="FairValueFairValueOfFinancialInstrumentsDetails" roleURI="http://www.allete.com/role/FairValueFairValueOfFinancialInstrumentsDetails">
        <link:definition>2411403 - Disclosure - Fair Value - Fair Value of Financial Instruments (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="FairValueRecurringFairValueMeasuresDetails" roleURI="http://www.allete.com/role/FairValueRecurringFairValueMeasuresDetails">
        <link:definition>2411402 - Disclosure - Fair Value - Recurring Fair Value Measures (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="FairValueTables" roleURI="http://www.allete.com/role/FairValueTables">
        <link:definition>2311301 - Disclosure - Fair Value (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="IncomeTaxExpense" roleURI="http://www.allete.com/role/IncomeTaxExpense">
        <link:definition>2118100 - Disclosure - Income Tax Expense</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="IncomeTaxExpenseDetails" roleURI="http://www.allete.com/role/IncomeTaxExpenseDetails">
        <link:definition>2418402 - Disclosure - Income Tax Expense (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="IncomeTaxExpenseDetailsCalc2" roleURI="http://www.allete.com/role/IncomeTaxExpenseDetailsCalc2">
        <link:definition>2418402 - Disclosure - Income Tax Expense (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="IncomeTaxExpenseTables" roleURI="http://www.allete.com/role/IncomeTaxExpenseTables">
        <link:definition>2318301 - Disclosure - Income Tax Expense (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="OperationsAndSignificantAccountingPolicies" roleURI="http://www.allete.com/role/OperationsAndSignificantAccountingPolicies">
        <link:definition>2101100 - Disclosure - Operations and Significant Accounting Policies</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="OperationsAndSignificantAccountingPoliciesAlleteCleanEnergyAssetAcquisitionDetails" roleURI="http://www.allete.com/role/OperationsAndSignificantAccountingPoliciesAlleteCleanEnergyAssetAcquisitionDetails">
        <link:definition>2401407 - Disclosure - Operations and Significant Accounting Policies - ALLETE Clean Energy Asset Acquisition (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="OperationsAndSignificantAccountingPoliciesDetails" roleURI="http://www.allete.com/role/OperationsAndSignificantAccountingPoliciesDetails">
        <link:definition>2401403 - Disclosure - Operations and Significant Accounting Policies (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="OperationsAndSignificantAccountingPoliciesNonControllingInterestDetails" roleURI="http://www.allete.com/role/OperationsAndSignificantAccountingPoliciesNonControllingInterestDetails">
        <link:definition>2401408 - Disclosure - Operations and Significant Accounting Policies - Non-Controlling Interest (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="OperationsAndSignificantAccountingPoliciesOtherIncomeDetails" roleURI="http://www.allete.com/role/OperationsAndSignificantAccountingPoliciesOtherIncomeDetails">
        <link:definition>2401404 - Disclosure - Operations and Significant Accounting Policies - Other Income (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="OperationsAndSignificantAccountingPoliciesPolicies" roleURI="http://www.allete.com/role/OperationsAndSignificantAccountingPoliciesPolicies">
        <link:definition>2201201 - Disclosure - Operations and Significant Accounting Policies (Policies)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="OperationsAndSignificantAccountingPoliciesSaleOfUSWaterServicesDetails" roleURI="http://www.allete.com/role/OperationsAndSignificantAccountingPoliciesSaleOfUSWaterServicesDetails">
        <link:definition>2401406 - Disclosure - Operations and Significant Accounting Policies - Sale of U.S. Water Services (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="OperationsAndSignificantAccountingPoliciesSupplementalStatementOfCashFlowsInformationDetails" roleURI="http://www.allete.com/role/OperationsAndSignificantAccountingPoliciesSupplementalStatementOfCashFlowsInformationDetails">
        <link:definition>2401405 - Disclosure - Operations and Significant Accounting Policies - Supplemental Statement of Cash Flows Information (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="OperationsAndSignificantAccountingPoliciesTables" roleURI="http://www.allete.com/role/OperationsAndSignificantAccountingPoliciesTables">
        <link:definition>2301302 - Disclosure - Operations and Significant Accounting Policies (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="PensionAndOtherPostretirementBenefitPlans" roleURI="http://www.allete.com/role/PensionAndOtherPostretirementBenefitPlans">
        <link:definition>2119100 - Disclosure - Pension and Other Postretirement Benefit Plans</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="PensionAndOtherPostretirementBenefitPlansDetails" roleURI="http://www.allete.com/role/PensionAndOtherPostretirementBenefitPlansDetails">
        <link:definition>2419402 - Disclosure - Pension and Other Postretirement Benefit Plans (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="PensionAndOtherPostretirementBenefitPlansTables" roleURI="http://www.allete.com/role/PensionAndOtherPostretirementBenefitPlansTables">
        <link:definition>2319301 - Disclosure - Pension and Other Postretirement Benefit Plans (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="RegulatoryMatters" roleURI="http://www.allete.com/role/RegulatoryMatters">
        <link:definition>2105100 - Disclosure - Regulatory Matters</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="RegulatoryMattersElectricRatesDetails" roleURI="http://www.allete.com/role/RegulatoryMattersElectricRatesDetails">
        <link:definition>2405402 - Disclosure - Regulatory Matters - Electric Rates (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="RegulatoryMattersMisoReturnOnEquityComplaintDetails" roleURI="http://www.allete.com/role/RegulatoryMattersMisoReturnOnEquityComplaintDetails">
        <link:definition>2405404 - Disclosure - Regulatory Matters - MISO Return on Equity Complaint (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="RegulatoryMattersNemadjiTrailEnergyCenterDetails" roleURI="http://www.allete.com/role/RegulatoryMattersNemadjiTrailEnergyCenterDetails">
        <link:definition>2405403 - Disclosure - Regulatory Matters - Nemadji Trail Energy Center (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="RegulatoryMattersRegulatoryAssetsAndLiabilitiesDetails" roleURI="http://www.allete.com/role/RegulatoryMattersRegulatoryAssetsAndLiabilitiesDetails">
        <link:definition>2405405 - Disclosure - Regulatory Matters - Regulatory Assets and Liabilities (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="RegulatoryMattersTables" roleURI="http://www.allete.com/role/RegulatoryMattersTables">
        <link:definition>2305301 - Disclosure - Regulatory Matters (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="ShortTermAndLongTermDebt" roleURI="http://www.allete.com/role/ShortTermAndLongTermDebt">
        <link:definition>2112100 - Disclosure - Short-Term and Long-Term Debt</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="ShortTermAndLongTermDebtDetails" roleURI="http://www.allete.com/role/ShortTermAndLongTermDebtDetails">
        <link:definition>2412402 - Disclosure - Short-Term and Long-Term Debt (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="ShortTermAndLongTermDebtFinancialCovenantsDetails" roleURI="http://www.allete.com/role/ShortTermAndLongTermDebtFinancialCovenantsDetails">
        <link:definition>2412403 - Disclosure - Short-Term and Long-Term Debt - Financial Covenants (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="ShortTermAndLongTermDebtTables" roleURI="http://www.allete.com/role/ShortTermAndLongTermDebtTables">
        <link:definition>2312301 - Disclosure - Short-Term and Long-Term Debt (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
    </xsd:appinfo>
  </xsd:annotation>
  <xsd:element abstract="true" id="ale_A2020MinnesotaGeneralRateReviewMember" name="A2020MinnesotaGeneralRateReviewMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ale_AFUDCEquityMember" name="AFUDCEquityMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ale_ALLETEBonds2.50DueAugust2030Member" name="ALLETEBonds2.50DueAugust2030Member" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ale_ALLETEBonds3.30DueAugust2050Member" name="ALLETEBonds3.30DueAugust2050Member" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ale_ALLETECleanEnergyAssetAcquisitionAbstract" name="ALLETECleanEnergyAssetAcquisitionAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ale_ALLETECleanEnergyMember" name="ALLETECleanEnergyMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ale_ALLETECleanEnergyOtherMember" name="ALLETECleanEnergyOtherMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ale_ATCMember" name="ATCMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ale_AlleteIncMember" name="AlleteIncMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ale_AlletePropertiesPerformanceAndMaintenanceObligationsMember" name="AlletePropertiesPerformanceAndMaintenanceObligationsMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ale_AlletesInvestmentInAtcRollForward" name="AlletesInvestmentInAtcRollForward" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element id="ale_AmortizationfromtheRemeasurementofDeferredIncomeTaxesforEquityMethodInvestments" name="AmortizationfromtheRemeasurementofDeferredIncomeTaxesforEquityMethodInvestments" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element id="ale_AmortizationofPowerPurchaseAgreements" name="AmortizationofPowerPurchaseAgreements" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element id="ale_ApproximateProceedsfromDivestitureofBusiness" name="ApproximateProceedsfromDivestitureofBusiness" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element id="ale_AvailableforsaleSecuritiesDebtMaturitiesAfterFiveYearsFairValue" name="AvailableforsaleSecuritiesDebtMaturitiesAfterFiveYearsFairValue" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="ale_AvailableforsaleSecuritiesDebtMaturitiesAfterOneYearThroughThreeYearsFairValue" name="AvailableforsaleSecuritiesDebtMaturitiesAfterOneYearThroughThreeYearsFairValue" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="ale_AvailableforsaleSecuritiesDebtMaturitiesAfterThreeYearsThroughFiveYearsFairValue" name="AvailableforsaleSecuritiesDebtMaturitiesAfterThreeYearsThroughFiveYearsFairValue" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element abstract="true" id="ale_BniCoalReclamationLiabilityMember" name="BniCoalReclamationLiabilityMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ale_Boswell12Member" name="Boswell12Member" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ale_CIPFinancialIncentiveMember" name="CIPFinancialIncentiveMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ale_CaddoMember" name="CaddoMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="ale_CapitalCostSpentToDate" name="CapitalCostSpentToDate" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="ale_CapitalCostsSpentToDateRecovered" name="CapitalCostsSpentToDateRecovered" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element abstract="true" id="ale_CapitalProjectMember" name="CapitalProjectMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="ale_CashPaidforAssetsAcquired" name="CashPaidforAssetsAcquired" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element abstract="true" id="ale_CoalCombustionResidualsMember" name="CoalCombustionResidualsMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ale_CombinedCycleNaturalGasFiredGeneratingFacilityMember" name="CombinedCycleNaturalGasFiredGeneratingFacilityMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ale_CommercialMember" name="CommercialMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="ale_CommunityDevelopmentDistrictObligationAnnualAssessment" name="CommunityDevelopmentDistrictObligationAnnualAssessment" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element id="ale_CommunityDevelopmentDistrictObligationOwnershipOfPropertyBenefited" name="CommunityDevelopmentDistrictObligationOwnershipOfPropertyBenefited" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="instant" />
  <xsd:element abstract="true" id="ale_ComponentofOtherIncomeExpenseOtherAxis" name="ComponentofOtherIncomeExpenseOtherAxis" nillable="true" substitutionGroup="xbrldt:dimensionItem" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ale_ComponentofOtherIncomeExpenseOtherDomain" name="ComponentofOtherIncomeExpenseOtherDomain" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ale_ContractMember" name="ContractMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ale_CorporateOtherOtherMember" name="CorporateOtherOtherMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ale_CostRecoveryRidersMember" name="CostRecoveryRidersMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ale_CurrentCostRecoveryRiderMember" name="CurrentCostRecoveryRiderMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ale_CustomerClassAxis" name="CustomerClassAxis" nillable="true" substitutionGroup="xbrldt:dimensionItem" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ale_CustomerClassDomain" name="CustomerClassDomain" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="ale_DebtCurrentGross" name="DebtCurrentGross" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="ale_DebtInstrumentActualIndebtednessToTotalCapitalRatio" name="DebtInstrumentActualIndebtednessToTotalCapitalRatio" nillable="true" substitutionGroup="xbrli:item" type="xbrli:pureItemType" xbrli:periodType="instant" />
  <xsd:element id="ale_DebtInstrumentInterestRateFloor" name="DebtInstrumentInterestRateFloor" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="ale_DebtInstrumentRequiredIndebtednessToTotalCapitalRatio" name="DebtInstrumentRequiredIndebtednessToTotalCapitalRatio" nillable="true" substitutionGroup="xbrli:item" type="xbrli:pureItemType" xbrli:periodType="instant" />
  <xsd:element id="ale_DebtLongTermandShortTermCombinedAmountGross" name="DebtLongTermandShortTermCombinedAmountGross" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="ale_DeferredCompensationFairValueDisclosure" name="DeferredCompensationFairValueDisclosure" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element abstract="true" id="ale_DocumentAndEntityInformationAbstract" name="DocumentAndEntityInformationAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element id="ale_EffectiveIncomeTaxRateReconciliationRegulatoryDifferences" name="EffectiveIncomeTaxRateReconciliationRegulatoryDifferences" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ale_ElectricRatesMember" name="ElectricRatesMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ale_EnvironmentalMattersLineItems" name="EnvironmentalMattersLineItems" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ale_EnvironmentalMattersTable" name="EnvironmentalMattersTable" nillable="true" substitutionGroup="xbrldt:hypercubeItem" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element id="ale_EquityMethodInvestmentApprovedReturnonCommonEquityIncludingIncentiveAdder" name="EquityMethodInvestmentApprovedReturnonCommonEquityIncludingIncentiveAdder" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="instant" />
  <xsd:element id="ale_EquityMethodInvestmentExpectedAdditionalInvestment" name="EquityMethodInvestmentExpectedAdditionalInvestment" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="ale_EstimatedCapitalExpendituresIncludingPastExpenditures" name="EstimatedCapitalExpendituresIncludingPastExpenditures" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="ale_ExpectedPeriodforCostsofCompliance" name="ExpectedPeriodforCostsofCompliance" nillable="true" substitutionGroup="xbrli:item" type="us-types:durationStringItemType" xbrli:periodType="duration" />
  <xsd:element id="ale_FERCAuthorizedReturnonCommonEquity" name="FERCAuthorizedReturnonCommonEquity" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="instant" />
  <xsd:element id="ale_FERCAuthorizedReturnonEquityIncludingIncentiveAdder" name="FERCAuthorizedReturnonEquityIncludingIncentiveAdder" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="instant" />
  <xsd:element abstract="true" id="ale_FERCMember" name="FERCMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ale_FuelAdjustmentClauseMember" name="FuelAdjustmentClauseMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="ale_FuelPurchasedPowerandGasUtility" name="FuelPurchasedPowerandGasUtility" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ale_GainLossonLandSalesMember" name="GainLossonLandSalesMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="ale_GainonSaleofAffiliateAftertax" name="GainonSaleofAffiliateAftertax" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element id="ale_GeneratingCapacityCounterpartyOwnedMW" name="GeneratingCapacityCounterpartyOwnedMW" nillable="true" substitutionGroup="xbrli:item" type="num:powerItemType" xbrli:periodType="instant" />
  <xsd:element id="ale_GeneratingCapacityJointlyOwnedMW" name="GeneratingCapacityJointlyOwnedMW" nillable="true" substitutionGroup="xbrli:item" type="num:powerItemType" xbrli:periodType="instant" />
  <xsd:element id="ale_GeneratingCapacitySubjecttoTaxEquityFinancing" name="GeneratingCapacitySubjecttoTaxEquityFinancing" nillable="true" substitutionGroup="xbrli:item" type="num:powerItemType" xbrli:periodType="duration" />
  <xsd:element id="ale_GeneratingCapacityUnderDevelopmentMW" name="GeneratingCapacityUnderDevelopmentMW" nillable="true" substitutionGroup="xbrli:item" type="num:powerItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ale_GeneratingFacilityAxisAxis" name="GeneratingFacilityAxisAxis" nillable="true" substitutionGroup="xbrldt:dimensionItem" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ale_GeneratingFacilityUnitNameDomain" name="GeneratingFacilityUnitNameDomain" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ale_GenerationTypeAxis" name="GenerationTypeAxis" nillable="true" substitutionGroup="xbrldt:dimensionItem" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ale_GenerationTypeDomain" name="GenerationTypeDomain" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ale_GlenUllinEnergyCenterMember" name="GlenUllinEnergyCenterMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ale_GreatNorthernTransmissionLineMember" name="GreatNorthernTransmissionLineMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ale_GuaranteeEntityandTypeAxis" name="GuaranteeEntityandTypeAxis" nillable="true" substitutionGroup="xbrldt:dimensionItem" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ale_GuaranteeEntityandTypeDomain" name="GuaranteeEntityandTypeDomain" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="ale_GuarantorObligationsCollateralHeldDirectlyorbyThirdPartiesAmount" name="GuarantorObligationsCollateralHeldDirectlyorbyThirdPartiesAmount" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element abstract="true" id="ale_IncreaseDecreaseInTaxAbstract" name="IncreaseDecreaseInTaxAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element id="ale_IncreaseDecreaseinAccountsPayableforCapitalAdditionstoPropertyPlantandEquipment" name="IncreaseDecreaseinAccountsPayableforCapitalAdditionstoPropertyPlantandEquipment" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ale_IndustrialMember" name="IndustrialMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ale_InterestandInvestmentEarningsMember" name="InterestandInvestmentEarningsMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="ale_InterimRatesCollectedtoDate" name="InterimRatesCollectedtoDate" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ale_JointlyOwnedbyALLETEandDairylandPowerCooperativeMember" name="JointlyOwnedbyALLETEandDairylandPowerCooperativeMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="ale_LongTermContractForPurchaseOfElectricPowerShareOfPlantOutputBeingPurchasedMw" name="LongTermContractForPurchaseOfElectricPowerShareOfPlantOutputBeingPurchasedMw" nillable="true" substitutionGroup="xbrli:item" type="num:powerItemType" xbrli:periodType="instant" />
  <xsd:element id="ale_LongTermContractForPurchaseOfElectricPowerShareOfPlantOutputPurchasedMw" name="LongTermContractForPurchaseOfElectricPowerShareOfPlantOutputPurchasedMw" nillable="true" substitutionGroup="xbrli:item" type="num:powerItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ale_LongtermContractMember" name="LongtermContractMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="ale_LongtermContractforPurchaseofElectricPowerTermofContractYears" name="LongtermContractforPurchaseofElectricPowerTermofContractYears" nillable="true" substitutionGroup="xbrli:item" type="xbrli:durationItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ale_LongtermContractforSaleofEnergyAxis" name="LongtermContractforSaleofEnergyAxis" nillable="true" substitutionGroup="xbrldt:dimensionItem" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ale_LongtermContractforSaleofEnergyDomain" name="LongtermContractforSaleofEnergyDomain" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ale_LongtermContractsforSaleofElectricPowerAxis" name="LongtermContractsforSaleofElectricPowerAxis" nillable="true" substitutionGroup="xbrldt:dimensionItem" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ale_LongtermContractsforSaleofElectricPowerDomain" name="LongtermContractsforSaleofElectricPowerDomain" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ale_LongtermPSAMember" name="LongtermPSAMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ale_MPUCMember" name="MPUCMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="ale_MWSoldUnderShorttermPSAs" name="MWSoldUnderShorttermPSAs" nillable="true" substitutionGroup="xbrli:item" type="num:powerItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ale_ManitobaHydroMember" name="ManitobaHydroMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ale_ManitobaHydroPpaExpires2035Member" name="ManitobaHydroPpaExpires2035Member" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ale_ManufacturedGasPlantMember" name="ManufacturedGasPlantMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ale_MedicarePartDRegulatoryAssetMember" name="MedicarePartDRegulatoryAssetMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ale_MinnesotaPowerMember" name="MinnesotaPowerMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ale_MinnesotaPowerShorttermPSAsin2020and2021Member" name="MinnesotaPowerShorttermPSAsin2020and2021Member" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ale_MinnkotaPowerMember" name="MinnkotaPowerMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ale_MinnkotaSalesAgreementMember" name="MinnkotaSalesAgreementMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ale_MunicipalMember" name="MunicipalMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ale_NaturalGasPPAMember" name="NaturalGasPPAMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ale_NemadjiTrailEnergyCenterMember" name="NemadjiTrailEnergyCenterMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ale_Nobles2Member" name="Nobles2Member" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ale_NonControllingInterestDetailsLineItems" name="NonControllingInterestDetailsLineItems" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ale_NonControllingInterestDetailsTable" name="NonControllingInterestDetailsTable" nillable="true" substitutionGroup="xbrldt:hypercubeItem" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ale_NorthDakotaInvestmentTaxCreditsSubjecttoRefundMember" name="NorthDakotaInvestmentTaxCreditsSubjecttoRefundMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="ale_OperatingandMaintenance" name="OperatingandMaintenance" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ale_OtherIncomeExpenseOtherAbstract" name="OtherIncomeExpenseOtherAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ale_OtherIncomeExpenseOtherLineItems" name="OtherIncomeExpenseOtherLineItems" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ale_OtherIncomeExpenseOtherMember" name="OtherIncomeExpenseOtherMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ale_OtherIncomeExpenseOtherTable" name="OtherIncomeExpenseOtherTable" nillable="true" substitutionGroup="xbrldt:hypercubeItem" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ale_OtherMember" name="OtherMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="ale_OtherPostretirementBenefitPlans" name="OtherPostretirementBenefitPlans" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element abstract="true" id="ale_OtherPowerSuppliersMember" name="OtherPowerSuppliersMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ale_PensionandOtherPostretirementBenefitPlansNonServiceCreditMember" name="PensionandOtherPostretirementBenefitPlansNonServiceCreditMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ale_PointinTimeMember" name="PointinTimeMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="ale_PowerPurchaseAgreementCurrentLiability" name="PowerPurchaseAgreementCurrentLiability" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="ale_PowerPurchaseAgreementNoncurrentLiability" name="PowerPurchaseAgreementNoncurrentLiability" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="ale_ProposedOngoingCustomerRateIncrease" name="ProposedOngoingCustomerRateIncrease" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="ale_ProvisionforInterimRateRefund" name="ProvisionforInterimRateRefund" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element id="ale_ProvisionforTaxReformRefund" name="ProvisionforTaxReformRefund" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ale_ProvisionforTaxReformRefundDomain" name="ProvisionforTaxReformRefundDomain" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ale_RateInformationByTypeDomain" name="RateInformationByTypeDomain" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ale_RateTypeAxis" name="RateTypeAxis" nillable="true" substitutionGroup="xbrldt:dimensionItem" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element id="ale_RecognitionofRightofuseAssetsandLeaseLiabilities" name="RecognitionofRightofuseAssetsandLeaseLiabilities" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ale_RegulatedOperationsMember" name="RegulatedOperationsMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ale_RegulatoryAssetsAndLiabilitiesLineItems" name="RegulatoryAssetsAndLiabilitiesLineItems" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ale_ResidentialMember" name="ResidentialMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ale_ResourcePackageMember" name="ResourcePackageMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ale_RetailCustomersMember" name="RetailCustomersMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="ale_RevenueOtherThanCustomerRevenue" name="RevenueOtherThanCustomerRevenue" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ale_SWLPMember" name="SWLPMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ale_SaleofU.S.WaterServicesAbstract" name="SaleofU.S.WaterServicesAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ale_ScheduleOfRegulatoryAssetsAndLiabilitiesTable" name="ScheduleOfRegulatoryAssetsAndLiabilitiesTable" nillable="true" substitutionGroup="xbrldt:hypercubeItem" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element id="ale_ScheduleofCashCashEquivalentsandRestrictedCashTableTextBlock" name="ScheduleofCashCashEquivalentsandRestrictedCashTableTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ale_SouthPeakMember" name="SouthPeakMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ale_SquareButteCoalFiredUnitMember" name="SquareButteCoalFiredUnitMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ale_SquareButteMember" name="SquareButteMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ale_SquareButtePpaMember" name="SquareButtePpaMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ale_SuperiorWIMember" name="SuperiorWIMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ale_SuretyBondsandLettersofCreditMember" name="SuretyBondsandLettersofCreditMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ale_TenaskaMember" name="TenaskaMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ale_TenaskaPPAMember" name="TenaskaPPAMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ale_TownCenterCommunityDevelopmentDistrictMember" name="TownCenterCommunityDevelopmentDistrictMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ale_TransmissionAxis" name="TransmissionAxis" nillable="true" substitutionGroup="xbrldt:dimensionItem" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ale_TransmissionDomain" name="TransmissionDomain" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ale_TransmissionFormulaRatesMember" name="TransmissionFormulaRatesMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="ale_TransmissionLineCapacityKv" name="TransmissionLineCapacityKv" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="instant" />
  <xsd:element abstract="true" id="ale_TransmissionLineItems" name="TransmissionLineItems" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element id="ale_TransmissionLineLengthMiles" name="TransmissionLineLengthMiles" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="instant" />
  <xsd:element id="ale_TransmissionServicesUtility" name="TransmissionServicesUtility" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ale_TransmissionTable" name="TransmissionTable" nillable="true" substitutionGroup="xbrldt:hypercubeItem" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ale_U.S.WaterServicesMember" name="U.S.WaterServicesMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="ale_UnamortizedDebtIssuanceExpenseDebtCurrent" name="UnamortizedDebtIssuanceExpenseDebtCurrent" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="ale_UnamortizedDebtIssuanceExpenseLongTermDebtExcludingCurrentMaturities" name="UnamortizedDebtIssuanceExpenseLongTermDebtExcludingCurrentMaturities" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="ale_UnsecuredTermLoanAmount" name="UnsecuredTermLoanAmount" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ale_UnsecuredTermLoanDueApril2021Member" name="UnsecuredTermLoanDueApril2021Member" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ale_UnsecuredTermLoanDuein2021Member" name="UnsecuredTermLoanDuein2021Member" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ale_WholesaleAndRetailContraAfudcMember" name="WholesaleAndRetailContraAfudcMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ale_WindTurbineGeneratorsMember" name="WindTurbineGeneratorsMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
</xsd:schema>
