<SUBMISSION>
<ACCESSION-NUMBER>0001181431-08-053442
<TYPE>4
<PUBLIC-DOCUMENT-COUNT>1
<PERIOD>20080916
<FILING-DATE>20080916
<DATE-OF-FILING-DATE-CHANGE>20080916
<REPORTING-OWNER>
<OWNER-DATA>
<CONFORMED-NAME>Hatamiya Lon
<CIK>0001335259
</OWNER-DATA>
<FILING-VALUES>
<FORM-TYPE>4
<ACT>34
<FILE-NUMBER>001-32393
<FILM-NUMBER>081074542
</FILING-VALUES>
<BUSINESS-ADDRESS>
<PHONE>5109856890
</BUSINESS-ADDRESS>
<MAIL-ADDRESS>
<STREET1>2000 POWELL STREET
<STREET2>SUITE 600
<CITY>EMERYVILLE
<STATE>CA
<ZIP>94608
</MAIL-ADDRESS>
</REPORTING-OWNER>
<ISSUER>
<COMPANY-DATA>
<CONFORMED-NAME>ENVIRONMENTAL POWER CORP
<CIK>0000805012
<ASSIGNED-SIC>4991
<IRS-NUMBER>042782065
<STATE-OF-INCORPORATION>DE
<FISCAL-YEAR-END>1231
</COMPANY-DATA>
<BUSINESS-ADDRESS>
<STREET1>120 WHITE PLAINS RD
<STREET2>SUITE 610
<CITY>TARRYTOWN
<STATE>NY
<ZIP>10591-5546
<PHONE>914-631-1435
</BUSINESS-ADDRESS>
<MAIL-ADDRESS>
<STREET1>120 WHITE PLAINS RD
<STREET2>SUITE 610
<CITY>TARRYTOWN
<STATE>NY
<ZIP>10591-5546
</MAIL-ADDRESS>
</ISSUER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>rrd218915.xml
<DESCRIPTION>SEPTEMBER 16 PURCHASE
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2008-09-16</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000805012</issuerCik>
        <issuerName>ENVIRONMENTAL POWER CORP</issuerName>
        <issuerTradingSymbol>( EPG )</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001335259</rptOwnerCik>
            <rptOwnerName>Hatamiya Lon</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>5322 ROGERS STREET</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>DAVIS</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>95618</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2008-09-16</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>1250</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>1.9932</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>2250</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <ownerSignature>
        <signatureName>/s/ Scott E. Pueschel, Attorney-in-Fact for Lon Hatamiya</signatureName>
        <signatureDate>2008-09-16</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SUBMISSION>
