<SUBMISSION>
<ACCESSION-NUMBER>0001181431-03-014430
<TYPE>4
<PUBLIC-DOCUMENT-COUNT>1
<PERIOD>20030717
<FILING-DATE>20030717
<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>500 MARKET ST
<STREET2>STE 1E
<CITY>PORTSMOUTH
<STATE>NH
<ZIP>03801
<PHONE>6034311780
</BUSINESS-ADDRESS>
<MAIL-ADDRESS>
<STREET1>500 MARKET ST
<STREET2>STE 1E
<CITY>PORTSMOUTH
<STATE>NH
<ZIP>03801
</MAIL-ADDRESS>
</ISSUER>
<REPORTING-OWNER>
<OWNER-DATA>
<CONFORMED-NAME>CRESCI JOE
<CIK>0001156302
</OWNER-DATA>
<FILING-VALUES>
<FORM-TYPE>4
<ACT>34
<FILE-NUMBER>000-15472
<FILM-NUMBER>03791375
</FILING-VALUES>
<BUSINESS-ADDRESS>
<STREET1>500 MARKET ST
<STREET2>SUITE 1E
<CITY>PORTSMOUTH
<STATE>NH
<ZIP>03801
<PHONE>6034311780
</BUSINESS-ADDRESS>
<MAIL-ADDRESS>
<STREET1>500 MARKET ST
<STREET2>SUITE 1E
<CITY>PORTSMOUTH
<STATE>NH
<ZIP>03801
</MAIL-ADDRESS>
</REPORTING-OWNER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>rrd13458.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>
    <schemaVersion>X0101</schemaVersion>

    <documentType>4</documentType>
<periodOfReport>2003-07-17</periodOfReport>
<notSubjectToSection16>0</notSubjectToSection16>
    <issuer>
        <issuerCik>0000805012</issuerCik>
        <issuerName>ENVIRONMENTAL POWER CORP</issuerName>
        <issuerTradingSymbol>( powr )</issuerTradingSymbol></issuer>
<reportingOwner>
<reportingOwnerId>
            <rptOwnerCik>0001156302</rptOwnerCik>
            <rptOwnerName>CRESCI JOE</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>  </rptOwnerStreet1>
            <rptOwnerStreet2>  </rptOwnerStreet2>
            <rptOwnerCity>  </rptOwnerCity>
            <rptOwnerState>  </rptOwnerState>
            <rptOwnerZipCode>  </rptOwnerZipCode>
        </reportingOwnerAddress>
            <reportingOwnerRelationship>
<isDirector>0</isDirector>
<isOfficer>1</isOfficer>
<isTenPercentOwner>1</isTenPercentOwner>
<isOther>0</isOther>
<officerTitle>Chairman</officerTitle>
<otherText></otherText></reportingOwnerRelationship></reportingOwner>
<nonDerivativeSecurity>
<securityTitle>
<value>Common Stock</value></securityTitle>
<transactionDate>
<value>2003-07-15</value></transactionDate>
<deemedExecutionDate>
<value>2003-07-15</value></deemedExecutionDate>
<transactionCoding>
<transactionFormType>4</transactionFormType>
<transactionCode>P</transactionCode>
<equitySwapInvolved>0</equitySwapInvolved></transactionCoding>
<transactionTimeliness>
<value></value></transactionTimeliness>
<transactionAmounts>
<transactionShares>
<value>191667</value></transactionShares>
<transactionValue>
<value>40250.07</value></transactionValue>
<transactionAcquiredDisposedCode>
<value>A</value></transactionAcquiredDisposedCode></transactionAmounts>
<postTransactionAmounts>
<sharesOwnedFollowingTransaction>
<value>5292118</value></sharesOwnedFollowingTransaction></postTransactionAmounts>
<ownershipNature>
<directOrIndirectOwnership>
<value>I</value></directOrIndirectOwnership>
<natureOfOwnership>
<value>See Below</value>
<footnoteId id="F1"/></natureOfOwnership></ownershipNature></nonDerivativeSecurity>
<nonDerivativeSecurity>
<securityTitle>
<value>Common Stock</value></securityTitle>
<transactionDate>
<value>2003-07-16</value></transactionDate>
<deemedExecutionDate>
<value>2003-07-16</value></deemedExecutionDate>
<transactionCoding>
<transactionFormType>4</transactionFormType>
<transactionCode>P</transactionCode>
<equitySwapInvolved>0</equitySwapInvolved></transactionCoding>
<transactionTimeliness>
<value></value></transactionTimeliness>
<transactionAmounts>
<transactionShares>
<value>191100</value></transactionShares>
<transactionValue>
<value>59733.00</value></transactionValue>
<transactionAcquiredDisposedCode>
<value>A</value></transactionAcquiredDisposedCode></transactionAmounts>
<postTransactionAmounts>
<sharesOwnedFollowingTransaction>
<value>5292115</value></sharesOwnedFollowingTransaction></postTransactionAmounts>
<ownershipNature>
<directOrIndirectOwnership>
<value>I</value></directOrIndirectOwnership>
<natureOfOwnership>
<value>See Below</value>
<footnoteId id="F1"/></natureOfOwnership></ownershipNature></nonDerivativeSecurity>
<footnotes>
<footnote id="F1">588,767 are direct ownership,  3,643,618 shares are held in a revocable trust for the benefit of members of Reporting Persons family, of which the Reporting person in a trustee. 1,000,000 shares deposited by Reporting Person into a voting trust on Novemeber 20, 1996 and in which the Reporting Person has beneficial ownership in such shares which are evidenced by a voting trust certificate held by the Cresci Family Limited Partnership of which the Reporting Person is the sole general partner with sole dispositive power.  59,730 shares held in trust for benefit of Reporting Person and his children.</footnote></footnotes>
<ownerSignature>
<signatureName>Joseph E. Cresci</signatureName>
<signatureDate>2003-07-17</signatureDate></ownerSignature></ownershipDocument>


</XML>
</TEXT>
</DOCUMENT>
</SUBMISSION>
