-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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MIC-Info: RSA-MD5,RSA,
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 jXkITd+YwG8M1pb3RjyOxA==

<SEC-DOCUMENT>0001181431-10-031160.txt : 20100603
<SEC-HEADER>0001181431-10-031160.hdr.sgml : 20100603
<ACCEPTANCE-DATETIME>20100603163059
ACCESSION NUMBER:		0001181431-10-031160
CONFORMED SUBMISSION TYPE:	D
PUBLIC DOCUMENT COUNT:		1
ITEM INFORMATION:		Rule 506
ITEM INFORMATION:		Investment Company Act Section 3(c)
ITEM INFORMATION:		Section 3(c)(7)
FILED AS OF DATE:		20100603
DATE AS OF CHANGE:		20100603
EFFECTIVENESS DATE:		20100603

FILER:

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			Energy Fund XV-B, L.P.
		CENTRAL INDEX KEY:			0001492977
		IRS NUMBER:				000000000
		STATE OF INCORPORATION:			DE

	FILING VALUES:
		FORM TYPE:		D
		SEC ACT:		1933 Act
		SEC FILE NUMBER:	021-142951
		FILM NUMBER:		10876282

	BUSINESS ADDRESS:	
		STREET 1:		865 FIGUEROA STREET, SUITE 1800
		CITY:			LOS ANGELES
		STATE:			CA
		ZIP:			90017
		BUSINESS PHONE:		(213) 244-0686

	MAIL ADDRESS:	
		STREET 1:		865 FIGUEROA STREET, SUITE 1800
		CITY:			LOS ANGELES
		STATE:			CA
		ZIP:			90017
</SEC-HEADER>
<DOCUMENT>
<TYPE>D
<SEQUENCE>1
<FILENAME>primary_doc.xml
<TEXT>
<XML>
<?xml version="1.0"?>
<edgarSubmission>

    <schemaVersion>X0704</schemaVersion>

    <submissionType>D</submissionType>

    <testOrLive>LIVE</testOrLive>

    <primaryIssuer>
        <cik>0001492977</cik>
        <entityName>Energy Fund XV-B, L.P.</entityName>
        <issuerAddress>
            <street1>865 Figueroa Street, Suite 1800</street1>
            <city>Los Angeles</city>
            <stateOrCountry>CA</stateOrCountry>
            <stateOrCountryDescription>CALIFORNIA</stateOrCountryDescription>
            <zipCode>90017</zipCode>
        </issuerAddress>
        <issuerPhoneNumber>213-244-6836</issuerPhoneNumber>
        <jurisdictionOfInc>DELAWARE</jurisdictionOfInc>
        <issuerPreviousNameList>
            <value>None</value>
        </issuerPreviousNameList>
        <edgarPreviousNameList>
            <value>None</value>
        </edgarPreviousNameList>
        <entityType>Limited Partnership</entityType>
        <yearOfInc>
            <withinFiveYears>true</withinFiveYears>
            <value>2010</value>
        </yearOfInc>
    </primaryIssuer>

    <relatedPersonsList>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>None</firstName>
                <lastName>TCW-EIG Alternative Investments, LLC</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>865 Figueroa Street, Suite 1800</street1>
                <city>Los Angeles</city>
                <stateOrCountry>CA</stateOrCountry>
                <stateOrCountryDescription>CALIFORNIA</stateOrCountryDescription>
                <zipCode>90017</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Promoter</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification></relationshipClarification>
        </relatedPersonInfo>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>R.</firstName>
                <middleName>Blair</middleName>
                <lastName>Thomas</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>TCW-EIG Alternative Investments, LLC</street1>
                <street2>865 Figueroa Street, Suite 1800</street2>
                <city>Los Angeles</city>
                <stateOrCountry>CA</stateOrCountry>
                <stateOrCountryDescription>CALIFORNIA</stateOrCountryDescription>
                <zipCode>90017</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Executive Officer</relationship>
                <relationship>Director</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification></relationshipClarification>
        </relatedPersonInfo>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>Kurt</firstName>
                <middleName>A.</middleName>
                <lastName>Talbot</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>TCW-EIG Alternative Investments, LLC</street1>
                <street2>865 Figueroa Street, Suite 1800</street2>
                <city>Los Angeles</city>
                <stateOrCountry>CA</stateOrCountry>
                <stateOrCountryDescription>CALIFORNIA</stateOrCountryDescription>
                <zipCode>90017</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Executive Officer</relationship>
                <relationship>Director</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification></relationshipClarification>
        </relatedPersonInfo>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>Randall</firstName>
                <middleName>S.</middleName>
                <lastName>Wade</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>TCW-EIG Alternative Investments, LLC</street1>
                <street2>865 Figueroa Street, Suite 1800</street2>
                <city>Los Angeles</city>
                <stateOrCountry>CA</stateOrCountry>
                <stateOrCountryDescription>CALIFORNIA</stateOrCountryDescription>
                <zipCode>90017</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Executive Officer</relationship>
                <relationship>Director</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification></relationshipClarification>
        </relatedPersonInfo>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>Michael</firstName>
                <middleName>E.</middleName>
                <lastName>Cahill</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>TCW-EIG Alternative Investments, LLC</street1>
                <street2>865 Figueroa Street, Suite 1800</street2>
                <city>Los Angeles</city>
                <stateOrCountry>CA</stateOrCountry>
                <stateOrCountryDescription>CALIFORNIA</stateOrCountryDescription>
                <zipCode>90017</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Director</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification></relationshipClarification>
        </relatedPersonInfo>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>Marc</firstName>
                <middleName>I.</middleName>
                <lastName>Stern</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>TCW-EIG Alternative Investments, LLC</street1>
                <street2>865 Figueroa Street, Suite 1800</street2>
                <city>Los Angeles</city>
                <stateOrCountry>CA</stateOrCountry>
                <stateOrCountryDescription>CALIFORNIA</stateOrCountryDescription>
                <zipCode>90017</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Director</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification></relationshipClarification>
        </relatedPersonInfo>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>Robert</firstName>
                <middleName>L.</middleName>
                <lastName>Vitale</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>TCW-EIG Alternative Investments, LLC</street1>
                <street2>865 Figueroa Street, Suite 1800</street2>
                <city>Los Angeles</city>
                <stateOrCountry>CA</stateOrCountry>
                <stateOrCountryDescription>CALIFORNIA</stateOrCountryDescription>
                <zipCode>90017</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Executive Officer</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification></relationshipClarification>
        </relatedPersonInfo>
    </relatedPersonsList>

    <offeringData>
        <industryGroup>
            <industryGroupType>Pooled Investment Fund</industryGroupType>
            <investmentFundInfo>
                <investmentFundType>Private Equity Fund</investmentFundType>
                <is40Act>false</is40Act>
            </investmentFundInfo>
        </industryGroup>
        <issuerSize>
            <revenueRange>Decline to Disclose</revenueRange>
        </issuerSize>
        <federalExemptionsExclusions>
            <item>06</item>
            <item>3C</item>
            <item>3C.7</item>
        </federalExemptionsExclusions>
        <typeOfFiling>
            <newOrAmendment>
                <isAmendment>false</isAmendment>
            </newOrAmendment>
            <dateOfFirstSale>
                <yetToOccur>true</yetToOccur>
            </dateOfFirstSale>
        </typeOfFiling>
        <durationOfOffering>
            <moreThanOneYear>true</moreThanOneYear>
        </durationOfOffering>
        <typesOfSecuritiesOffered>
            <isEquityType>true</isEquityType>
            <isPooledInvestmentFundType>true</isPooledInvestmentFundType>
        </typesOfSecuritiesOffered>
        <businessCombinationTransaction>
            <isBusinessCombinationTransaction>false</isBusinessCombinationTransaction>
            <clarificationOfResponse></clarificationOfResponse>
        </businessCombinationTransaction>
        <minimumInvestmentAccepted>0</minimumInvestmentAccepted>
        <salesCompensationList>
            <recipient>
                <recipientName>Not Applicable</recipientName>
                <recipientCRDNumber>None</recipientCRDNumber>
                <associatedBDName>Credit Suisse Securities (USA) LLC</associatedBDName>
                <associatedBDCRDNumber>816</associatedBDCRDNumber>
                <recipientAddress>
                    <street1>11 Madison Avenue</street1>
                    <city>New York</city>
                    <stateOrCountry>NY</stateOrCountry>
                    <stateOrCountryDescription>NEW YORK</stateOrCountryDescription>
                    <zipCode>10010</zipCode>
                </recipientAddress>
                <statesOfSolicitationList>
                    <value>All States</value>
                </statesOfSolicitationList>
                <foreignSolicitation>true</foreignSolicitation>
            </recipient>
        </salesCompensationList>
        <offeringSalesAmounts>
            <totalOfferingAmount>Indefinite</totalOfferingAmount>
            <totalAmountSold>0</totalAmountSold>
            <totalRemaining>Indefinite</totalRemaining>
            <clarificationOfResponse></clarificationOfResponse>
        </offeringSalesAmounts>
        <investors>
            <hasNonAccreditedInvestors>false</hasNonAccreditedInvestors>
            <totalNumberAlreadyInvested>0</totalNumberAlreadyInvested>
        </investors>
        <salesCommissionsFindersFees>
            <salesCommissions>
                <dollarAmount>28625000</dollarAmount>
                <isEstimate>true</isEstimate>
            </salesCommissions>
            <findersFees>
                <dollarAmount>0</dollarAmount>
            </findersFees>
            <clarificationOfResponse>This represents an estimate of the aggregate fees payable in respect of the offering of Energy Fund XV, L.P., Energy Fund XV-A, L.P., Energy Fund XV-B, L.P., Energy Fund XV (Cayman), L.P. and Energy Investors XV (Scotland), L.P.</clarificationOfResponse>
        </salesCommissionsFindersFees>
        <useOfProceeds>
            <grossProceedsUsed>
                <dollarAmount>0</dollarAmount>
            </grossProceedsUsed>
            <clarificationOfResponse></clarificationOfResponse>
        </useOfProceeds>
        <signatureBlock>
            <authorizedRepresentative>false</authorizedRepresentative>
            <signature>
                <issuerName>Energy Fund XV-B, L.P.</issuerName>
                <signatureName>/s/ R. Blair Thomas</signatureName>
                <nameOfSigner>R. Blair Thomas</nameOfSigner>
                <signatureTitle>Chief Executive Officer</signatureTitle>
                <signatureDate>2010-06-03</signatureDate>
            </signature>
        </signatureBlock>
    </offeringData>
</edgarSubmission>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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