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Exhibit 10.91

                    SECOND AMENDMENT TO AMENDED AND RESTATED
                            PARTICIPATION AGREEMENT

     This  SECOND  AMENDMENT  TO  AMENDED  AND  RESTATED PARTICIPATION
AGREEMENT, dated as of September 2, 1998 (this "Amendment"), is made and entered
                                                ---------                       
into by and among SCRUBGRASS GENERATING COMPANY, L.P., a Delaware limited
partnership ("Lessor"), BUZZARD POWER CORPORATION, a Delaware corporation
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("Lessee"), ENVIRONMENTAL POWER CORPORATION, a Delaware corporation ("EPC"),
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BANKERS TRUST COMPANY as trustee under the Indenture ("Bond Trustee"), BANKERS
                                                       ------------           
TRUST COMPANY as disbursement agent ("Disbursement Agent"), and CREDIT
                                      ------------------              
LYONNAIS, acting through its New York Branch ("Credit Lyonnais") as agent for
                                               ---------------               
the Bond LOC Issuer, the Contract LOC issuer, and the Banks (Credit Lyonnais
acting in such capacity, the "Agent").
                              -----   

     WHEREAS, Lessor, Lessee, EPC, Bond Trustee, Disbursement Agent and Agent
are parties to that certain Amended and Restated Participation Agreement (the
"Participation Agreement") dated December 22, 1995, which sets forth certain
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agreements and re1ationships between and among themselves relating to the
construction, financing, leasing, and operation of a coal and coal-waste fired
approximately 85 megawatt (net) small power production plant located in Vanango
County, Pennsylvania (the "Project"); and

     WHEREAS, Section 12.2 of the Participation Agreement provides that a
general partner in Lessor, including Pine Power Leasing, Inc. ("Pine"), may not,
                                                                ----            
with certain exceptions, make any transfer or assignment of all or any portion
of its general partnership interest in Lessor and certain corresponding rights
and obligations except in a Permitted Transfer (as defined in the Participation
Agreement); and

     WHEREAS, Appendix  1 of the Participation Agreement defines the term
"Permitted Transfer" to include (a) sales, transfers or other dispositions which
(i) are to Persons approved by the Majority Banks (which approval shall not be
unreasonably withheld), who assume all obligations of Lessor and under the Loan
Documents and (ii) after giving effect thereto, do not result in the occurrence
of any Default or Event of Default under any Transaction Document or (b) any
sale, transfer, assignment or other disposition of a general partner interest
permitted by Section 10.02 of the Amended and Restated Reimbursement Agreement;
and

     WHEREAS, simultaneously herewith, Lessor, the Consenting Banks, the Agent,
National Westminster Bank Plc. acting through its New York Branch, in its
capacity as the Bond LOC issuer, and Landesbank Hessen-Thuringen Girozentrale,
New York Branch, in its capacity as the Contract LOC Issuer will execute that
certain Amendment Number 4 to the Reimbursement Agreement ("Agreement  No 4")
                                                            ---------------  
setting forth the terms and conditions under which the Consenting Banks are
willing to consent to the Proposed Transfer, such consent to be effective upon
satisfaction of such terms and conditions (the "Effective Date"), as defined in
                                                --------------                 
Amendment No. 4; and

     WHEREAS, subject to the terms and conditions set forth in that certain
Purchase 

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Agreement dated as of March 6, 1998 (the "Purchase Agreement"), between
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Bechtel Generating Company, Inc. ("BGCI") and Cogentrix Energy, Inc.
                                   ----                             
("Cogentrix"), BGCI has agreed to cause Pine to sell and transfer to
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Cogentrix/Scrubgrass, Inc., a Delaware corporation and an indirect subsidiary of
Cogentrix ("Substitute Partner"), and Substitute Partner has agreed to purchase
            ------------------                                                 
and accept, Pine's twenty percent (20%) general partnership interest (the
"Interest") in Lessor (the "Proposed Transfer"); and
                            -----------------       

     WHEREAS, Lessor, Lessee, EPC, Bond Trustee, Disbursement Agent and Agent
desire to amend the Participation Agreement as set forth below:

     NOW THEREFORE, in consideration of the premises and of the mutual covenants
and agreements herein, and of other good and valuable consideration, the receipt
and sufficiency of which are hereby acknowledged, the parties hereto, intending
to be legally bound, agree as follows:

     1.  Definitions. Unless otherwise defined herein, capitalized terms have
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the meanings ascribed to them in the Participation Agreement.

     2.  Amendments to the Participation Agreement. Effective on the Effective
         -----------------------------------------                            
Date, the Participation Agreement shall be amended as follows:

          a. Section 1.1 of the Participation Agreement is hereby amended and
replaced in its entirety by a new Section 1.1 as follows:

     "Definitions; Rules of Construction. Capitalized terms used herein shall,
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     unless the context otherwise requires or they are otherwise defined herein,
     have the meanings set forth in Appendix I hereto. References in this
     Agreement to articles, sections, paragraphs and clauses are to articles,
     sections, paragraphs and clauses of this Agreement unless otherwise
     indicated. At any time, all references herein to any agreement or appendix,
     schedule or exhibit to such agreement shall be to such agreement, appendix,
     schedule or exhibit as such Agreement, Appendix, Schedule or Exhibit shall
     have been properly amended through such time. All references to a
     particular entity shall include a reference to such entity's successors and
     permitted assigns. Except as otherwise required by the context, such
     definitions shall be equally applicable to the singular or plural forms of
     the terms defined. The words "herein,"  "hereof" and "hereunder" shall
     refer to this Agreement as a whole and not to any particular section or
     subsection of this Agreement."



          b.  Appendix I of the Participation Agreement shall be amended to
include the following terms:

     "Clearfield Fuel Purchase Agreement" shall mean the Amended and Restated
      ----------------------------------                                     
     Fuel Purchase Agreement dated as of June 1, 1996 between Lessor and
     Clearfield Properties, Inc.

     "Cogentrix/Scrubgrass" shall mean Cogentrix/Scrubgrass, Inc., a Delaware
      --------------------                                                   
     corporation.

     "Fuel Services Agreement" shall mean the Fuel Services Agreement dated as
      -----------------------                                                 
     of June 1, 

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     1996 by and between Lessor and Fuel Site Operator.

     "Fuel Site Operator" shall mean U. S. Operating Services Company, a
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     California general partnership, in its status as operator under the Fuel
     Services Agreement, and any successor operator.

     "Leechburg Waste Disposal Agreement" shall mean the Amended and Restated
      ----------------------------------                                     
     Waste Disposal Agreement dated as of June 1, 1996 between Lessor and
     Leechburg Properties, Inc.

          c.  Appendix I of the Participation Agreement shall be amended to
     delete the terms "Pine" and "Bechtel Power".

          d.  The definition of "General Partners" set forth in Appendix I of
     the Participation Agreement shall be amended and restated in its entirety
     as follows:

     "General Partners" shall mean Cogentrix/Scrubgrass, Falcon, SPC and all
      ----------------                                                      
     other Persons admitted as general partners of Lessor pursuant to the terms
     of the Partnership Agreement."

     3.  Governing Law. This Amendment shall be governed by and construed in
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accordance with the laws of the State of New York, without regard to any other
applicable conflict of law provisions.

     4.  Amendments. This Amendment may not be amended, altered, modified or
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revoked without the prior written consent of all parties hereto, except in
accordance with the requirements under the Reimbursement Agreement for
modifications thereto.

     5.  Headings.  All headings in this Amendment are included only for
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convenience and ease of reference and shall not be considered in the
construction and interpretation of any provision hereof.

     6.  Binding Nature and Benefit. This Amendment shall be binding upon and
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inure to the benefit of each party hereto and their respective successors and
assignors.

     7.  Counterparts. This Amendment may be executed in multiple counterparts,
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each of which shall be deemed an original for all purposes, but all of which
together shall constitute one and the same instrument.

     8.  Omnibus Consent. All of the undersigned parties consent to this
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Amendment and each and every action to be taken hereunder and as described
herein.

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          IN WITNESS WHEREOF, the parties have caused this Amendment to be duly
executed and delivered as of the day and year first above written.

                          SCRUBGRASS GENERATING COMPANY, L.P.
                          a Delaware limited partnership

                          By:     illegible                 
                               ------------------------
                               Name:     illegible
                                     ----------------------------
                               Title:    illegible
                                     ---------------------------  

                          BUZZARD POWER CORPORATION
                          a Delaware corporation

                          By:  /s/ William D. Linehan
                               -------------------------       
                               Name:  William D. Linehan
                                      ---------------------------
                               Title: Chief Financial Officer
                                      --------------------------

                          ENVIRONMENTAL POWER CORPORATION,
                          a Delaware corporation

                          By:  /s/ William D. Linehan
                               -------------------------       
                               Name:  William D. Linehan
                                      ---------------------------- 
                               Title: Treasurer
                                      ----------------------------

                          CREDIT LYONNAIS,
                          acting through its New York branch,, as Agent

                          By:     illegible               
                               --------------------------
                               Name:     illegible                  
                                      ----------------------------
                               Title:    illegible                  
                                      ---------------------------- 

                          BANKERS TRUST COMPANY,
                          as trustee under the Indenture

                          By:     illegible                      
                               ---------------------------                 
                               Name:       illegible             
                                      ----------------------------            
                               Title:      illegible             
                                      ----------------------------

                          BANKERS TRUST COMPANY,
                          as disbursement agent

                          By:     illegible                       
                               ---------------------------        
                               Name:       illegible             
                                      ----------------------------
                               Title:      illegible             
                                      ----------------------------

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