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Exhibit 10.22

SECOND AMENDMENT TO
PARTICIPATION AGREEMENT
(Undivided Interest in the Conemaugh Facility)

        THIS SECOND AMENDMENT TO PARTICIPATION AGREEMENT dated as of June 18,
2003 (this "Amendment"), among (i) RELIANT ENERGY MID-ATLANTIC POWER HOLDINGS,
LLC (formerly known as Sithe Pennsylvania Holdings, LLC), a Delaware limited
liability company, as Facility Lessee, (ii) CONEMAUGH LESSOR GENCO LLC, a
Delaware limited liability company, as Owner Lessor, (iii) WILMINGTON TRUST
COMPANY, a banking corporation organized and existing under the laws of the
State of Delaware, not in its individual capacity, except as expressly provided
herein and in the Participation Agreement referred to below, but solely as
manager under the LLC Agreement, (iv) WILMINGTON TRUST COMPANY, a banking
corporation organized and existing under the laws of the State of Delaware in
its individual capacity, (v) PSEGR CONEMAUGH GENERATION, LLC, a Delaware limited
liability company, as Owner Participant, (vi) DEUTSCHE BANK TRUST COMPANY
AMERICAS, as successor to BANKERS TRUST COMPANY, a banking corporation organized
and existing under the laws of the State of New York, not in its individual
capacity, except as expressly provided herein and in the Participation Agreement
referred to below, but solely as trustee under the Lease Indenture, and
(vii) DEUTSCHE BANK TRUST COMPANY AMERICAS, as successor to BANKERS TRUST
COMPANY, a banking corporation organized and existing under the laws of the
State of New York, not in its individual capacity, except as expressly provided
herein and in the Participation Agreement referred to below, but solely as
trustee under the Pass Through Trust Agreement.

        WHEREAS, the Facility Lessee, the Owner Lessor, the Lessor Manager,
Wilmington Trust Company, the Owner Participant, the Lease Indenture Trustee and
the Pass Through Trustee have entered into that certain Participation Agreement
dated as of August 24, 2000, as amended by that certain First Amendment to
Participation Agreement dated as of November 15, 2001 (together with any and all
amendments and modifications thereof, the "Participation Agreement");
capitalized terms used herein and not otherwise defined have the same meaning as
in the Participation Agreement; and

        WHEREAS, the parties to the Participation Agreement desire to amend the
terms thereof as provided for herein;

        NOW, THEREFORE, in consideration of the premises, and for other good and
valuable consideration, the receipt and sufficiency of which are hereby
acknowledged, the parties hereto agree as follows:

        Section 1.    Amendments to the Participation Agreement.    

        (a)   Section 5.8 of the Participation Agreement is hereby amended by
deleting it in its entirety and inserting in lieu thereof:

        Section 5.8.    Credit Support.    So long as the Certificates are
outstanding:

        (a)   The Facility Lessee shall maintain for the benefit of the Owner
Lessor (or its permitted assignee), Qualifying Credit Support (i) issued in
favor of the Owner Lessor (or its permitted assignee) by a Qualifying Credit
Support Issuer in the case of a letter of credit, surety bond, or guarantee,
provided that Facility Lessee shall not be deemed in default of this clause (i)
solely as a result of a Qualifying Credit Support Issuer ceasing to be such so
long as Facility Lessee complies with Section 5.8(d); (ii) with an available
amount equal to the greater of (A) the Periodic Lease Rent scheduled to be paid
in the next six months and (B) 50% of the Periodic Lease Rent scheduled to be
paid in the next twelve months, provided that (1) the available amount of the
Credit Support on any Rent Payment Date shall remain in effect (and not be
adjusted as required above) until the earlier of (A) the date upon which the
amount due on such Rent Payment Date shall have been paid in full and (B) the
tenth (10th) day after such Rent Payment Date and

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(2) the Facility Lessee shall not be deemed in default of this clause (ii)
solely as a result of a reduction in the available amount of the Credit Support
resulting from a drawing thereunder so long as the Facility Lessee complies with
Section 5.8(e) (as of the Closing Date, the minimum available amount of the
Qualifying Credit Support required to be in effect during the term of the
Certificates pursuant to this clause (ii) is set forth on Schedule 9 hereto
(which Schedule does not give effect to any Adjustment Item pursuant to
Section 3.5 of the Facility Lease, or any issuance of Additional Lessor Notes or
any Exchange pursuant to Section 14.3 (the Facility Lessee acknowledges that the
occurrence of any such event may require an increase in the required minimum
available amount)); and (iii) if such Qualifying Credit Support is in the form
of a letter of credit, surety bond, or guarantee, its stated expiration date
shall not be earlier than one year after the date of issuance of such Qualifying
Credit Support (such Qualifying Credit Support to be assigned by the Owner
Lessor to the Lease Indenture Trustee in accordance with the Lease Indenture).
The type of Qualifying Credit Support shall be selected by the Facility Lessee,
and the Lease Indenture Trustee agrees to exchange one type of Qualifying Credit
Support for another type upon the Facility Lessee's written request to the Lease
Indenture Trustee with notice to the Owner Lessor, which exchange may be made no
earlier than five Business Days after the Lease Indenture Trustee's receipt of
such request and the Owner Lessor's receipt of such notice.

        (b)   If Qualifying Credit Support in the form of a letter of credit,
surety bond, or guarantee shall have an expiration date prior to the maturity
date of the Certificates and the Facility Lessee does not elect to replace such
Qualifying Credit Support with the proceeds of a drawing thereon, the Facility
Lessee shall cause such Qualifying Credit Support to be extended or replaced (in
compliance with Section 5.8(f)) on or before the date that is at least 30 days
prior to such Qualifying Credit Support's expiration date.

        (c)   If the Facility Lessee or any Qualifying Credit Support Issuer, as
applicable, elects to terminate any Qualifying Credit Support in the form of a
letter of credit, surety bond, or guarantee prior to the maturity date of the
Certificates other than by allowing a drawing thereon, the Facility Lessee or
such Qualifying Credit Support Issuer, as the case may be, shall notify the
Owner Lessor and the Lease Indenture Trustee of its intent to terminate the
Qualifying Credit Support 60 days prior to the proposed termination date and the
Facility Lessee shall replace (in compliance with Section 5.8(f)) such
Qualifying Credit Support on or before a date that is 30 days prior to the
proposed termination date.

        (d)   If at any time subsequent to the issuance of a Qualifying Credit
Support in the form of a letter of credit, surety bond, or guarantee, the
Qualifying Credit Support Issuer ceases to be a Qualifying Credit Support
Issuer, the Facility Lessee shall, within 60 days of receiving Actual Knowledge
of such Qualifying Credit Support Issuer's failing to be a Qualifying Credit
Support Issuer, replace (in compliance with Section 5.8(f)) such credit support
with a replacement Qualifying Credit Support.

        (e)   If at any time a Qualifying Credit Support is drawn upon or
applied by Lease Indenture Trustee as assignee of the Owner Lessor to pay
Periodic Lease Rent not paid when due or drawn in full under Section 9(d)(iv),
the Facility Lessee shall have 90 days to reinstate the availability under the
drawn, or the amount of the applied, Qualifying Credit Support (or provide a new
Qualifying Credit Support (in compliance with Section 5.8(f))) in an amount
equal to the amount then required by Section 5.8(a)(ii), it being understood
that any amount drawn under a Qualifying Credit Support in the form of a letter
of credit, surety bond, or guarantee and not applied to pay Periodic Lease Rent
not paid when due shall be held by the Lease Indenture Trustee as Qualifying
Credit Support.

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        (f)    The Facility Lessee shall be permitted, from time to time, to
replace any Qualifying Credit Support issued or established with a replacement
Qualifying Credit Support (including any replacement by receipt of proceeds of a
drawing of Qualifying Credit Support under Section 9(d)(iv)) so long as (i) the
Facility Lessee has certified to the Lease Indenture Trustee that such
replacement Qualifying Credit Support complies with the provisions hereof;
(ii) the Owner Lessor assigns such replacement Qualifying Credit Support to the
Lease Indenture Trustee; (iii) in the case of Qualifying Credit Support that is
(A) a letter of credit, surety bond, or guarantee, the Facility Lessee delivers
(or causes to be delivered) to the Owner Lessor and the Lease Indenture Trustee
an opinion of counsel addressed to each of them (in form reasonably satisfactory
to the Owner Lessor) to the effect that the obligations of the Qualifying Credit
Support Issuer under any replacement Qualifying Credit Support that is not a
letter of credit are valid and enforceable and that the Lien of the Lease
Indenture in any such Qualifying Credit Support constitutes a valid, enforceable
and perfected security interest in any such Qualifying Credit Support (in each
case, subject to customary qualifications) and (B) cash or Cash Equivalents, the
Facility Lessee delivers (or causes to be delivered) to the Owner Lessor and the
Lease Indenture Trustee (in form reasonably satisfactory to the Owner Lessor) an
opinion of counsel addressed to each of them within 10 Business Days after the
payment of the drawing on the Qualifying Credit Support giving rise to such cash
or Cash Equivalents to the effect that (1) the Lien of the Lease Indenture in
any such Qualifying Credit Support constitutes a valid, enforceable and
perfected security interest in any such Qualifying Credit Support (subject to
customary qualifications) securing the Facility Lessee's obligations to pay
Periodic Lease Rent or Termination Value and (2) any documentation executed by
the Facility Lessee in connection therewith is a legal, valid and binding
obligation of the Facility Lessee enforceable in accordance with its terms; and
(iv) there shall be no interruption in the coverage provided by the Qualifying
Credit Support in consequence of such optional replacement. Upon any replacement
satisfying the conditions of this Section 5.8(f), the Lease Indenture Trustee
shall return any replaced Qualifying Credit Support to the Facility Lessee and
execute any discharges or releases reasonably requested by the Facility Lessee.

        (g)   With respect to Qualifying Credit Support in the form of cash or
Cash Equivalents, (i) the Lease Indenture Trustee as assignee of the Owner
Lessor shall invest any cash held as Qualifying Credit Support in Cash
Equivalents as directed by the Facility Lessee in writing so long as the opinion
delivered under Section 5.8(f)(iii)(B) covers the perfection of the Lien of the
Lease Indenture in such Cash Equivalents; (ii) any earnings from such Qualifying
Credit Support received by the Lease Indenture Trustee shall be distributed to
the Facility Lessee upon the Facility Lessee's written request made no more
frequently than once each calendar month so long as no Lease Event of Default
has occurred and is continuing or would be caused thereby and such distribution
would otherwise be permitted under the Operative Documents; and (iii) in the
event that no Significant Lease Default or Lease Event of Default has occurred
and is continuing and the Facility Lessee provides for the benefit of the Owner
Lessor Qualifying Credit Support that is a letter of credit, surety bond, or
guarantee in the amount required to be maintained pursuant to Section 5.8(a),
the Lease Indenture Trustee shall return to the Facility Lessee the balance of
such Qualifying Credit Support.

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        (b)   Paragraph (d) of Section 9 of the Participation Agreement is
hereby amended by deleting it in its entirety and inserting in lieu thereof:

        (d)   Promptly upon (and in any event within three (3) Business Days
after) any of the following, (i) the Lease Indenture Trustee's obtaining Actual
Knowledge (or receipt of notice) of a Lease Default under clause (a) of
Section 16 of the Facility Lease, (ii) receipt by the Lease Indenture Trustee of
notice of a Lease Event of Default under clause (g) or (h) of Section 16 of the
Facility Lease, (iii) acceleration of the Notes after the occurrence and during
the continuance of a Lease Event of Default, or (iv) the 30th day prior to the
expiration date or early termination date of any Qualifying Credit Support that
is a letter or credit, surety bond, or guarantee (without such Qualifying Credit
Support being extended or replaced in accordance with Section 5.8), the Lease
Indenture Trustee shall make an appropriate presentation under such Qualifying
Credit Support in accordance with its terms (such presentation to be in an
amount equal to, in the case of clause (i) above, the aggregate amount of such
past due Periodic Lease Rent or Termination Value (but not in excess of the
amount then available thereunder), and in the case of clauses (ii), (iii) and
(iv) above, the full amount then available thereunder). The proceeds of any such
drawing shall be applied to the Periodic Lease Rent or Termination Value as such
amounts become due and payable. The proceeds of any drawing pursuant to
Section 9(d)(iv) shall be held by the Lease Indenture Trustee as collateral for
the payment of Periodic Lease Rent or Termination Value and applied to Periodic
Lease Rent and Termination Value as such amounts become due and payable in
accordance with the terms of the Operative Documents; provided that, in the
event that no Significant Lease Default or Lease Event of Default has occurred
and is continuing and the Facility Lessee provides for the benefit of the Owner
Lessor Qualifying Credit Support that is a letter of credit, surety bond, or
guarantee in the amount required to be maintained pursuant to Section 5.8(a),
the Lease Indenture Trustee shall return to the Facility Lessee any unapplied
proceeds of such drawing.

The Lease Indenture Trustee as assignee of the Owner Lessor shall also apply any
Qualifying Credit Support that is cash or Cash Equivalents to the Periodic Lease
Rent or Termination Value as such amounts become due and payable in accordance
with the terms of the Operative Documents after (i) the Lease Indenture
Trustee's obtaining Actual Knowledge (or receipt of notice) of a Lease Default
under clause (a) of Section 16 of the Facility Lease, (ii) receipt by the Lease
Indenture Trustee of notice of a Lease Event of Default under clause (g) or
(h) of Section 16 of the Facility Lease, or (iii) acceleration of the Notes
after the occurrence and during the continuance of a Lease Event of Default.

        (c)   Appendix A to the Participation Agreement is hereby amended by
deleting the definition of "Operative Documents" and inserting in lieu thereof:

"Operative Documents" shall mean the Participation Agreement, the Deed and Bill
of Sale, the Facility Lease, the Site Lease and Sublease, the Assignment and
Reassignment of Owners Agreement, the Lease Indenture, the Lessor Notes, the
Pass Through Trust Agreements, the Certificates, the LLC Agreement, the Tax
Indemnity Agreement, the Subsidiary Guaranty, the Qualifying Credit Support (and
any transfer letter or other instrument with respect thereto or any cash
collateral agreement or security agreement executed in connection therewith),
the Lease Pledge Agreement, the Intercreditor Agreement, and the OP Guarantee.

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        (d)   Appendix A to the Participation Agreement is hereby amended by
deleting the definition of "Qualifying Credit Support" and inserting in lieu
thereof:

"Qualifying Credit Support" shall mean (i) an irrevocable unconditional stand by
letter of credit, surety bond or guarantee substantially in the form of
Exhibit C-1, Exhibit C-2, or Exhibit C-3, respectively, to the Participation
Agreement, issued in favor of the Owner Lessor (or its permitted assignee) by a
Qualifying Credit Support Issuer (and assigned to the Lease Indenture Trustee),
provided, that (A) any secured reimbursement obligations in respect of any such
Qualifying Credit Support secured with property of the Facility Lessee or the
Subsidiary Guarantors are secured only with property of the Facility Lessee and
the Subsidiary Guarantors not otherwise securing the Facility Lessee's
obligations under the Facility Lease and (B) in the case of a surety bond, each
of S&P and Moody's must confirm its then current rating on the Certificates
prior to the Facility Lessee's first use of a surety bond as Qualifying Credit
Support or (ii) cash or Cash Equivalents obtained by the Lease Indenture Trustee
as assignee of the Owner Lessor pursuant to a draw on any other form of
Qualifying Credit Support and held for the benefit of the Owner Lessor (or its
permitted assignee), pursuant to a cash collateral agreement or other security
agreement reasonably acceptable to the Lease Indenture Trustee executed and
delivered to the Lease Indenture Trustee within 10 Business Days after the
payment of the drawing on the Qualifying Credit Support giving rise to such cash
or Cash Equivalents as security for the Facility Lessee's obligation to pay
Periodic Lease Rent or Termination Value under the Facility Lease (it being
explicitly understood with respect to credit support in the form of cash or Cash
Equivalents that such credit support is for security purposes only and is not a
prepayment of rent).

        Section 2.    Conditions to Effectiveness.    This Amendment shall
become effective as of the date (the "Effective Date") when:

        (a)   an officer of each of the parties hereto shall have executed and
delivered a counterpart hereof; and

        (b)   the Facility Lessee has executed and delivered to each of the
parties hereto a certificate stating that each of the following shall have
occurred:

        (i)    receipt by the Lease Indenture Trustee of evidence that all
necessary consents to this Amendment have been obtained;

        (ii)   receipt by the Lease Indenture Trustee of an opinion of counsel
pursuant to Section 8.3 of the Lease Indenture that the Lease Indenture
Trustee's execution of this Amendment is permitted; and

        (iii)  receipt by the Owner Participant of an opinion of Shearman &
Sterling with respect to any tax consequences of this Amendment reasonably
acceptable to the Owner Participant.

        Section 3.    Ratification of Related Documents.    The Participation
Agreement, as amended hereby, and each of the other Operative Documents is
hereby ratified and confirmed to be in full force and effect. To the extent that
the amendments set forth above cause conforming amendments to the Operative
Documents, by virtue of such Operative Documents incorporating by reference
(directly, indirectly, specifically or through the General Provisions of the
Appendix A to the Participation Agreement) provisions of either the
Participation Agreement or Appendix A to the Participation Agreement, all such
conforming amendments to the Operative Documents are hereby approved.

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        Section 4.    Limitations.    The modifications set forth herein are
limited precisely as written, and shall not be deemed to (a) be a consent to, or
waiver or modification of, any other term or condition of the Participation
Agreement or any of the other Operative Documents, or (b) prejudice any right or
rights which any Transaction Party may now have or may have in the future under
or in connection with the Participation Agreement or any of the other Operative
Documents. In the event of a conflict between this Amendment and any of the
foregoing documents, the terms of this Amendment shall be controlling.

        Section 5.    Choice of Law.    This Amendment and the rights and
obligations of the parties hereunder shall be construed in accordance with and
be governed by the laws of the State of New York without giving effect to the
conflicts of laws provisions thereof except New York General Obligations Law
Section 5-1401.

        Section 6.    Descriptive Headings.    The descriptive headings of the
several Sections of this Amendment are inserted for convenience only and shall
not be deemed to affect the meaning or construction of any of the provisions
hereof.

        Section 7.    Entire Agreement.    This Amendment, the Operative
Documents and the documents referred to herein represent the entire
understanding of the parties hereto regarding the subject matter hereof and
supersede all prior and contemporaneous oral and written agreements of the
parties hereto with respect to the subject matter hereof. There are no unwritten
oral agreements between the parties.

        Section 8.    Counterparts.    This Amendment may be executed in any
number of counterparts and by parties hereto on separate counterparts, each
counterpart, when so executed and delivered, shall constitute an original
instrument, and all such counterparts shall constitute but one and the same
instrument.

[Signature page follows.]

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        IN WITNESS WHEREOF, the parties hereto have caused this Amendment to be
duly executed and delivered by their respective officers thereunto duly
authorized.

    RELIANT ENERGY MID-ATLANTIC POWER
HOLDINGS, LLC, as Facility Lessee
 
 
By:
/s/  WILLIAM S. WALLER, JR.      

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    Name: William S. Waller, Jr.     Title: Vice President and Treasurer
 
 
CONEMAUGH LESSOR GENCO LLC,
as Owner Lessor
 
 
By: WILMINGTON TRUST COMPANY, not in its individual capacity but solely as
Lessor Manager under the LLC Agreement
 
 
By:
/s/  ROBERT P. HINES, JR.      

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    Name: Robert P. Hines, Jr.     Title: Senior Financial Services Officer
 
 
PSEGR CONEMAUGH GENERATION, LLC
 
 
By:
/s/  CHRISTOPHER P. KELLEHER      

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    Name: Christopher P. Kelleher     Title: Vice President
 
 
DEUTSCHE BANK TRUST COMPANY
AMERICAS, as successor to
BANKERS TRUST COMPANY, not in its individual capacity, except to the extent
provided herein, but as Lease Indenture Trustee under the Lease Indenture
 
 
By:
/s/  MARION F. ZINOWSKI      

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    Name: Marion F. Zinowski     Title: Vice President
 
 
DEUTSCHE BANK TRUST COMPANY
AMERICAS, as successor to
BANKERS TRUST COMPANY, not in its individual capacity, except to the extent
provided herein, but as Pass Through Trustee under the Pass Through Trust
Agreement
 
 
By:
/s/  MARION F. ZINOWSKI      

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    Name: Marion F. Zinowski     Title: Vice President
 
 
WILMINGTON TRUST COMPANY, in its
individual capacity
 
 
By:
/s/  ROBERT P. HINES, JR.      

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    Name: Robert P. Hines, Jr.     Title: Senior Financial Services Officer

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Exhibit 10.22 SECOND AMENDMENT TO PARTICIPATION AGREEMENT