<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2008-08-11</periodOfReport>

    <notSubjectToSection16>false</notSubjectToSection16>

    <issuer>
        <issuerCik>0000811156</issuerCik>
        <issuerName>CMS ENERGY CORP</issuerName>
        <issuerTradingSymbol>CMS</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001186618</rptOwnerCik>
            <rptOwnerName>BARBA GLENN P</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>ONE ENERGY PLAZA</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>JACKSON</rptOwnerCity>
            <rptOwnerState>MI</rptOwnerState>
            <rptOwnerZipCode>49201</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>false</isDirector>
            <isOfficer>true</isOfficer>
            <isTenPercentOwner>false</isTenPercentOwner>
            <isOther>false</isOther>
            <officerTitle>VP, Controller, CAO</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2008-08-11</value>
            </transactionDate>
            <deemedExecutionDate>
                <value>2008-08-11</value>
            </deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>J</transactionCode>
                <equitySwapInvolved>false</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>9000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>37099</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                    <footnoteId id="F2"/>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Forfeiture of Restricted Stock granted in 2005 pursuant to provisions of the Performance Incentive Stock Plan of CMS Energy Corporation.</footnote>
        <footnote id="F2">Total includes 36,900 shares of Restricted Stock of which 28,920 shares are nominal.  (The nominal shares received will be determined by the passage of time and achievement of performance objectives under the Performance Incentive Stock Plan of CMS Energy Corporation.)</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>Catherine M. Reynolds, Attny-in-Fact</signatureName>
        <signatureDate>2008-08-11</signatureDate>
    </ownerSignature>
</ownershipDocument>
