<SEC-DOCUMENT>0001104659-25-045520.txt : 20250507
<SEC-HEADER>0001104659-25-045520.hdr.sgml : 20250507
<ACCEPTANCE-DATETIME>20250507160514
ACCESSION NUMBER:		0001104659-25-045520
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20250505
FILED AS OF DATE:		20250507
DATE AS OF CHANGE:		20250507

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			MIDDLETON PAUL B
		CENTRAL INDEX KEY:			0001224978
		ORGANIZATION NAME:           	

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-34392
		FILM NUMBER:		25921211

	MAIL ADDRESS:	
		STREET 1:		PLUG POWER INC.
		STREET 2:		968 ALBANY SHAKER RD.
		CITY:			LATHAM
		STATE:			NY
		ZIP:			12110

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			PLUG POWER INC
		CENTRAL INDEX KEY:			0001093691
		STANDARD INDUSTRIAL CLASSIFICATION:	ELECTRICAL INDUSTRIAL APPARATUS [3620]
		ORGANIZATION NAME:           	04 Manufacturing
		EIN:				223672377
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		125 VISTA BOULEVARD
		CITY:			SLINGERLANDS
		STATE:			NY
		ZIP:			12159
		BUSINESS PHONE:		5187827700

	MAIL ADDRESS:	
		STREET 1:		125 VISTA BOULEVARD
		CITY:			SLINGERLANDS
		STATE:			NY
		ZIP:			12159
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>tm2514240-1_4seq1.xml
<DESCRIPTION>OWNERSHIP DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0508</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2025-05-05</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001093691</issuerCik>
        <issuerName>PLUG POWER INC</issuerName>
        <issuerTradingSymbol>PLUG</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001224978</rptOwnerCik>
            <rptOwnerName>MIDDLETON PAUL B</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O PLUG POWER INC.</rptOwnerStreet1>
            <rptOwnerStreet2>125 VISTA BOULEVARD</rptOwnerStreet2>
            <rptOwnerCity>SLINGERLANDS</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>12159</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>CFO &amp; Executive VP</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <aff10b5One>0</aff10b5One>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2025-05-05</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>F</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionTimeliness></transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>17081</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0.84</value>
                    <footnoteId id="F2"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>1558064</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>56047</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>401(k) Plan</value>
                    <footnoteId id="F3"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Tendered to Issuer to satisfy tax withholding obligations of the Reporting Person incurred in connection with the vesting of the Reporting Person's restricted stock awards.</footnote>
        <footnote id="F2">Pursuant to the Plug Power Inc. 2021 Stock Option and Incentive Plan, as amended, each share was tendered to Issuer at the price per share on the closing date of May 2, 2025.</footnote>
        <footnote id="F3">The Reporting Person holds 56,047 shares of common stock in Plug Power Inc.'s 401(k) plan. The information in this report is based on a plan statement as of May 6, 2025.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Gerard L. Conway, Jr., Attorney-in-Fact</signatureName>
        <signatureDate>2025-05-07</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
