<PAGE>

                         FIRST AMENDMENT TO LOAN AGREEMENT


     This FIRST AMENDMENT TO LOAN AGREEMENT (this "Amendment"), made and 
entered into as of November 30, 1998, is by and between Cogeneration 
Corporation of America, formerly known as NRG Generating (U.S.) Inc., a 
Delaware corporation ("CogenAmerica"), and CogenAmerica Funding Inc., 
formerly known as NRGG Funding Inc., a Delaware corporation (each a 
"Borrower" and collectively, the "Borrowers"), and NRG Energy, Inc., a 
Delaware corporation (the "Lender").
     
                                      RECITALS
     
     1.   The Lender and the Borrowers entered into a Supplemental Loan 
Agreement dated as of December 10, 1997 (the "Loan Agreement"); and
     
     2.   The Borrowers desire to amend certain provisions of the Loan 
Agreement, and the Lender has agreed to make such amendments, subject to the 
terms and conditions set forth in this Amendment.
     
                                     AGREEMENT
     
     NOW, THEREFORE, for good and valuable consideration, the receipt and 
adequacy of which are hereby acknowledged, the parties hereto hereby covenant 
and agree to be bound as follows:
     
     SECTION 1.  CAPITALIZED TERMS.  Capitalized terms used herein and not 
otherwise defined herein shall have the meanings assigned to them in the Loan 
Agreement, unless the context shall otherwise require.  For purposes of the 
Loan Agreement, CogenAmerica shall continue to be referred to as "NRGG" and 
CogenAmerica Funding Inc. shall continue to be referred to as "Funding".
     
     SECTION 2.  AMENDMENTS.  The Loan Agreement is hereby amended as follows:
     
          2.1  DEFINITIONS
     
               (a)  The definitions of "Base Rate", "Funding Date," "Notes," 
          "NRG Equity Guaranty" and "NRGG Equity Guaranty" contained in 
          Section 1.01 of the Loan Agreement are amended to read in their 
          entireties as follows:
     
                    "Base Rate" means (a) a rate per annum equal to the Prime 
               Rate for that date PLUS one and one-half percent (1.5%) PLUS 
               two percent (2%) during the period commencing on October 30, 
               1998 until such time as the Borrowers have provided the Lender 
               with evidence, reasonably satisfactory to the Lender, that (i) 
               the "Possible Event of Default" (as defined in the MeesPierson 
               Waiver Letter) has been absolutely and irrevocably waived by 
               the lenders party to the MeesPierson Credit Agreement or has 
               been cured by NRGG, (ii) no "Event of Default" as defined in 
               the MeesPierson Credit Agreement (nor any event or 

<PAGE>

               circumstance which with the giving of notice or the passage of 
               time, or both, would constitute an "Event of Default") has 
               occurred and is then continuing, whether or not any temporary 
               or contingent waiver may be in effect with respect to such 
               "Event of Default," and (iii) the "Margin" (as defined under 
               the MeesPierson Credit Agreement) has been reduced by the 
               lenders party to the MeesPierson Credit Agreement to the rate 
               in effect immediately prior to October 1, 1998 and (b) for any 
               date not falling within the period described in clause (a), a 
               rate per annum equal to the Prime Rate for that date PLUS one 
               and one-half percent (1.5%).

                    "Funding Date" shall mean any date upon which the Lender 
               makes a Loan to the Borrowers pursuant to the terms of this 
               Agreement.

                    "Note" means the joint and several Note of the Borrowers 
               substantially in the form attached hereto as Exhibit A.

                    "NRC Equity Guaranty" shall have the meaning assigned 
               thereto in Section 2.03.

                    "NRGG Equity Guaranty" shall have the meaning assigned 
               thereto in Section 2.02.

               (b)  Section 1.01 of the Loan Agreement is further amended by 
          adding thereto the following definitions of "Amount Advanced," 
          "Initial Funding Date," "MeesPierson Credit Agreement," 
          "MeesPierson Waiver Letter," "NRG Morris Inc." and "Prime Rate" in 
          correct alphabetical order:

                    "Amount Advanced" shall mean the aggregate amount of all 
               Loan advances made by the Lender under this Loan Agreement, 
               and shall not be reduced by any principal payment made by the 
               Borrowers to the Lender.

                    "Initial Funding Date" shall mean October 30, 1998.
                    
                    "MeesPierson Credit Agreement" shall mean that certain 
               Credit Agreement dated December 17,1997 entered into by and 
               among NRGG and MeesPierson Capital Corp. and the other lenders 
               party thereto.

                    "MeesPierson Waiver Letter" shall mean that certain 
               waiver letter between NRGG and MeesPierson Capital Corp. dated 
               as of August 14,1998, under the MeesPierson Credit Agreement.

          "NRG Morris Inc." shall mean CogenAmerica Morris Inc., formerly known
     as NRG Morris Inc., a Delaware corporation.

                    "Prime Rate" shall mean at the time any determination 
               thereof is to be made, the fluctuating interest rate per annum 
               announced from time to time by The Chase Manhattan Bank, New 
               York, New York, as its "Prime Rate" (or, if otherwise 
               denominated, such bank's reference rate for interest rate 
               calculations on general commercial loans), which rate is not 
               necessarily the lowest or best rate which such bank may at any 
               time and 

<PAGE>

               from time to time charge any of its customers.

          2.2  LOAN.  Section 2.01 of the Loan Agreement is amended to read 
     in its entirety as follows:

          Section 2.01   LOAN. Subject to the terms and conditions hereof, 
     the Lender agrees to make one or more loans to the Borrowers, each on a 
     Funding Date prior to March 31, 1999, in an aggregate principal amount 
     with respect to all such loans not to exceed $22,000,000 (individually 
     or collectively, as the context may require, the "Loan"). Amounts paid 
     on the Loan may not be reborrowed.

          2.3  MATURITY.  Section 2.04 of the Loan Agreement is amended to 
     read in its entirety as follows:

               Section 2.04  MATURITY.  The Loan shall mature in its entirety on
          December 31, 2004.

          2.4  AMORTIZATION  Article 2 of the Loan Agreement is amended to 
     add new Section 2.05(e) as follows:

               (e)  If on any payment date set forth on the Amortization 
          Schedule the Amount Advanced is less than $22,000,000, then the 
          principal payment date shall be reduced to the amount equal to (i) 
          the principal payment set forth on the Amortization Schedule 
          multiplied by (ii) the ratio of (A) the Amount Advanced to (B) 
          $22,000,000. 

          2.5  CONDITIONS PRECEDENT.  Article 3 of the Loan Agreement is 
     amended by adding new Section 3.02 as follows:

                    SECTION 3.02.  CONDITIONS TO ADDITIONAL LOANS AFTER THE 
               INITIAL FUNDING DATE.  The obligation of the Lender on any 
               Funding Date after the Initial Funding Date to make any 
               additional Loan is subject to the satisfaction, or waiver by 
               the Lender, immediately prior to or concurrent with the making 
               of such Loan (or at such other time specified below), of the 
               following conditions:

                         (a)  RESOLUTIONS; NOTICE OF BORROWING.  The Lender 
                    shall have received from the Borrowers a copy of the 
                    resolutions of the Board of Directors of each Borrower 
                    authorizing the requested borrowing, certified as true 
                    and accurate by the Secretary or Assistant Secretary of 
                    each Borrower, and, at least three Business Days prior to 
                    the Funding Date, the signed notice of borrowing 
                    specified in Section 2.07, in form and substance 
                    satisfactory to the Lender.  The notice of borrowing 
                    shall include (i) an acknowledgment by the Borrowers of 
                    the outstanding amounts of principal of and accrued 
                    interest on the Note and (ii) a certification from each 
                    Borrower that all conditions precedent to funding have 
                    been satisfied.

                         (b)  OPINION OF COUNSEL.  The Lender shall have 


<PAGE>

                    received an opinion of counsel to the Borrowers and to 
                    NRG Morris Inc. in form and substance satisfactory to the 
                    Lender.

                         (c)  REPRESENTATIONS TRUE; NO DEFAULT.  Each 
                    representation and warranty of the Borrowers hereunder 
                    and under the Pledge Agreement and the other Credit 
                    Documents shall be accurate and complete in all material 
                    respects as of each Funding Date and no Default or Event 
                    of Default shall have occurred hereunder.

                         (d)  FEES AND EXPENSES.  The Borrowers shall have 
                    paid to the Lender the fees and expenses set forth in 
                    Section 9.04 and all reasonable costs and expenses 
                    incurred by the Lender in connection with the making of 
                    any Loan on any Funding Date, including the reasonable 
                    fees and disbursements of counsel to the Lender.
                         
          2.6  ARTICLE 6.

          (a)  The opening paragraph of Article 6 of the Loan Agreement is
     amended to read in its entirety as follows:

               The Borrowers hereby covenant and undertake with the Lender 
          that, from the date hereof and so long as any principal, interest 
          or other moneys are owing in respect of this Agreement, under the 
          Note or under any of the Security Documents or so long as the fall 
          amount of the Loan has not been drawn pursuant to Section 2.01:

          (b)  Article 6 of the Loan Agreement is further amended to add new
     Section 6.01(s) as follows:


               (s)  Promptly upon obtaining knowledge thereof (and in any 
          event within five (5) days thereof), inform the Lender of the 
          occurrence of (i) any event which would constitute an "Event of 
          Default" under and as defined in the MeesPierson Credit Agreement 
          or of any event which, with the giving of notice or lapse of time, 
          or both, would constitute an "Event" of Default" thereunder, (ii) 
          receipt of any notice from MeesPierson Capital Corp. that (A) an 
          "Event of Default" has occurred under the MeesPierson Credit 
          Agreement, (B) an event which, with the giving of notice or lapse 
          of time, or both, would constitute an "Event of Default" thereunder 
          has occurred, or (C) any waiver or forbearance of any "Event of 
          Default" thereunder has expired or been terminated, (iii) receipt 
          by NRGG of any agreement or notice from MeesPierson Capital Corp., 
          or from any other lender party to the MeesPierson Credit Agreement, 
          waiving any term, condition, representation or covenant applicable 
          to NRGG under the MeesPierson Credit Agreement or any of the other 
          agreements, documents or instruments executed and delivered in 
          connection therewith, or of the covenants described therein, or 
          consenting to any modification of the obligations or duties of NRGG 
          with respect to the same, and (iv) any change in the status or 
          terms of the financial 


<PAGE>

          accommodations extended under the MeesPierson Credit Agreement, 
          including without limitation, any change with respect to or 
          affecting the MeesPierson Waiver Letter.

          2.7  ACCELERATION.  Section 7.02 of the Loan Agreement is amended to
     read in its entirety as follows:

               SECTION 7.02.  ACCELERATION.  If an Event of Default (other 
          than an Event of Default specified in Section 7.01(5) or (6) with 
          respect to a Borrower) occurs and is continuing, the Lender by 
          notice to a Borrower may declare the principal of and accrued 
          interest on the Loan to be due and payable and may terminate any 
          obligation of the Lender to make any Loans pursuant to Article 2 or 
          any Section thereof.  Upon such declaration, all outstanding 
          principal of and accrued interest on the Loan shall be due and 
          payable immediately. If an Event of Default specified in Section 
          7.01(5) or (6) with respect to a Borrower occurs, the principal of 
          and interest on the Loans shall IPSO FACTO become and be 
          immediately due and payable without any declaration or other act on 
          the part of the Lender and, unless the Lender otherwise elects, any 
          obligation of the Lender to make any Loans pursuant to Article 2 or 
          any Section thereof shall terminate.  The Lender by notice to a 
          Borrower may rescind an acceleration or any termination of 
          obligation to extend credit and the consequences of either such 
          action. No such rescission shall affect any subsequent Default or 
          impair any right consequent thereto.

          2.8  FUNDING DATE.  All references to "Funding Date" in Sections 
     5(i) (Insurance), 5(1) (ERISA), 6.01(p) (Maintenance of Insurance). 7.03 
     (Default and Remedies) and 7.04 (Other Remedies) shall be amended to 
     refer to "Initial Funding Date".

          2.9  FEES.  Sections 9.04(a) and (b) of the Loan Agreement are 
     amended by deleting the term "Funding Date" as it appears therein and 
     inserting in lieu thereof the term "Initial Funding Date".

          2.10 AMENDED NOTE.  Exhibit A to the Loan Agreement is hereby 
     amended to read as set forth on EXHIBIT A-1 attached to this Amendment 
     which is made a part of the Loan Agreement as Exhibit A thereto.

     SECTION 3.  EFFECTIVENESS OF AMENDMENTS. The amendments contained in 
this Amendment shall become effective upon delivery by the Borrowers of, and 
compliance by the Borrowers with, the following:

          3.1  This Amendment and the promissory note in the form of EXHIBIT 
     A-1 hereto (the "Amended Note") each duly executed by the Borrowers.

          3.2  A copy of the resolutions of the Board of Directors of each 
     Borrower authorizing the execution, delivery and performance of this 
     Amendment and the Amended Note certified as true and accurate by its 
     Secretary or Assistant Secretary, along with a copy of the Bylaws of 
     each Borrower and a certification by such Secretary or Assistant 
     Secretary (i) certifying that the Bylaws of such Borrower delivered 
     therewith are true and accurate, and (ii) identifying each officer of 
     such Borrower authorized to 

<PAGE>

     execute this Amendment, the Amended Note and any other instrument or 
     agreement executed by such Borrower in connection with this Amendment 
     (collectively, the "Amendment Documents"), and certifying as to 
     specimens of such officer's signature and such officer's incumbency in 
     such offices as such officer holds.

          3.3  Certified copies of all documents evidencing any necessary 
     corporate action, consent or governmental or regulatory approval (if 
     any) with respect to this Amendment, including without limitation, the 
     consent of the lenders to the MeesPierson Credit Agreement and 
     MeesPierson Capital Corp. as "Agent" pursuant to the terms and 
     conditions of that certain Subordination Agreement dated as of December 
     10, 1997, made by the Lender in favor of MeesPierson Capital Corp. and 
     the lenders party to the MeesPierson Credit Agreement and the consent of 
     The Chase Manhattan Bank as Collateral Agent pursuant to the terms and 
     conditions of that certain Subordination Agreement dated as of December 
     12, 1997 made by the Lender in favor of The Chase Manhattan Bank as 
     Collateral Agent.

          3.4  An opinion of counsel to the Borrowers and to NRG Morris Inc., 
     addressed to the Lender and dated the date of execution and delivery of 
     this Amendment, covering the matters set forth in EXHIBIT B hereto, duly 
     executed by said counsel.

          3.5  A good standing certificate for the Borrowers from the State 
     of Delaware and from all other States in which the Borrowers are doing 
     business issued in each case as of a date satisfactory to the Lender.

          3.6  A certificate of a responsible officer of each Borrower 
     certifying as to the matters set forth in Section 4.1 below.

          3.7  The Borrowers shall have satisfied such other conditions as 
     specified by the Lender, including payment of all unpaid legal fees and 
     expenses incurred by the Lender through the date of this Amendment in 
     connection with the Loan Agreement and the Amendment Documents.

     SECTION 4.  REPRESENTATIONS, WARRANTIES, AUTHORITY, NO ADVERSE CLAIM.

          4.1  REASSERTION OF REPRESENTATIONS AND WARRANTIES, NO DEFAULT.  
     The Borrowers hereby represent that on and as of the date hereof and 
     after giving effect to this Amendment (a) all of the representations and 
     warranties contained in the Loan Agreement are true, correct and 
     complete in all respects as of the date hereof as though made on and as 
     of such date, except for changes permitted by the terms of the Loan 
     Agreement, and (b) there will exist no Default or Event of Default under 
     the Loan Agreement as amended by this Amendment which is not subject to 
     a written waiver executed by the Lender or with respect to which the 
     Lender has not agreed in writing to forbear.

          4.2  AUTHORITY, NO CONFLICT, NO CONSENT REQUIRED. Each Borrower 
     represents and warrants that such Borrower has the power and legal right 
     and authority to enter into the Amendment Documents and has duly 
     authorized as appropriate the execution and delivery of the Amendment 
     Documents and other agreements and documents executed and delivered by 
     such Borrower in connection herewith or therewith 


<PAGE>

     by proper corporate action, and none of the Amendment Documents nor the 
     agreements contained herein or therein contravene or constitute a 
     default under any agreement, instrument or indenture to which such 
     Borrower is a party or a signatory or a provision of such Borrower's 
     Certificate of Incorporation, Bylaws or any other agreement or 
     requirement of law, or result in the imposition of any lien or 
     encumbrance on any of its property under any agreement binding on or 
     applicable to such Borrower or any of its property except, if any, in 
     favor of the Lender. Each Borrower represents and warrants that no 
     consent, approval or authorization of or registration or declaration 
     with any Person, including but not limited to any governmental 
     authority, is required in connection with the execution and delivery by 
     such Borrower of the Amendment Documents or other agreements and 
     documents executed and delivered by such Borrower in connection 
     therewith or the performance of obligations of such Borrower therein 
     described, except for those which such Borrower has obtained or provided 
     and as to which such Borrower has delivered certified copies of 
     documents evidencing each such action to the Lender.

          4.3  NO ADVERSE CLAIM. The Borrowers warrant, acknowledge and agree 
     that no events have been taken place and no circumstances exist at the 
     date hereof which would give either Borrower a basis to assert a 
     defense, offset or counterclaim to any claim of the Lender with respect 
     to the Borrowers' obligations under the Loan Agreement as amended by 
     this Amendment.

          4.4. MEESPIERSON CREDIT AGREEMENT.  The Borrowers represent and 
     warrant that they have delivered to the Lender true and correct copies 
     of all material documents in connection with the MeesPierson Credit 
     Agreement and the obligations thereunder, including, without limitation, 
     all waiver and forbearance agreements, and that such documents and 
     agreements, in the respective forms delivered to the Lender, embody the 
     entire agreements and understandings between the parties thereto with 
     respect to the matters therein and remain in full force and effect 
     without supplement, amendment or other modification.
          
     SECTION 5.  AFFIRMATION OF LOAN AGREEMENT, FURTHER REFERENCES, 
AFFIRMATION OF SECURITY INTEREST.  The Lender and the Borrowers each 
acknowledge and affirm that the Loan Agreement, as hereby amended, is hereby 
ratified and confirmed in all respects and all terms, conditions and 
provisions of the Loan Agreement, except as amended by this Amendment, shall 
remain unmodified and in full force and effect.  All references in any 
document or instrument to the Loan Agreement are hereby amended and shall 
refer to the Loan Agreement as amended by this Amendment. The Borrowers 
confirm to the Lender that the Borrowers' obligations under the Loan 
Agreement, as amended by this Amendment are and continue to be secured by the 
security interest granted by Funding and NRG Morris Inc. in favor of the 
Lender under that certain Subordinated Pledge and Security Agreement dated as 
of December 10, 1997, and all of the terms, conditions, provisions, 
agreements, requirements, promises, obligations, duties, covenants and 
representations of the Borrowers under such documents and any and all other 
documents and agreements entered into with respect to the obligations under 
the Loan Agreement are incorporated herein by reference and are hereby 
ratified and affirmed in all respects by the Borrowers. Funding hereby 
ratifies and reaffirms all terms, conditions and provisions of the Assignment 
and Assumption Agreement. NRGG hereby ratifies and reaffirms all terms, 


<PAGE>

conditions and provisions of the NRGG Equity Guaranty.

     SECTION 6.  MERGER AND INTEGRATION, SUPERSEDING EFFECT.  This Amendment 
and the Amended Note, from and after the date hereof, embodies the entire 
agreement and understanding between the parties hereto and supersedes and has 
merged into this Amendment all prior oral and written agreements on the same 
subjects by and between the parties hereto, including without limitation, 
that certain Note of the Borrowers dated October 30, 1998 in the principal 
amount of $8,902,750.59 and payable to the order of the Lender and that 
certain loan request made by the Borrowers by letter dated October 30, 1998, 
with the effect that this Amendment, shall control with respect to the 
specific subjects hereof and thereof.

     SECTION 7.  SEVERABILITY.  Whenever possible, each provision of this 
Amendment and the other Amendment Documents and any other statement, 
instrument or transaction contemplated hereby or thereby or relating hereto 
or thereto shall be interpreted in such manner as to be effective, valid and 
enforceable under the applicable law of any jurisdiction, but, if any 
provision of this Amendment, the other Amendment Documents or any other 
statement, instrument or transaction contemplated hereby or thereby or 
relating hereto or thereto shall be held to be prohibited, invalid or 
unenforceable under the applicable law, such provision shall be ineffective 
in such jurisdiction only to the extent of such prohibition, invalidity or 
unenforceability, without invalidating or rendering unenforceable the 
remainder of such provision or the remaining provisions of this Amendment, 
the other Amendment Documents or any other statement, instrument or 
transaction contemplated hereby or thereby or relating hereto or thereto in 
such jurisdiction, or affecting the effectiveness, validity or enforceability 
of such provision in any other jurisdiction.

     SECTION 8.  SUCCESSORS.  The Amendment Documents shall be binding upon 
the Borrowers and the Lender and their respective successors and assigns, and 
shall inure to the benefit of the Borrowers and the Lender and the successors 
and assigns of the Lender.

     SECTION 9.  LEGAL EXPENSES.  The Borrowers agree to reimburse the 
Lender, upon execution of this Amendment, for all reasonable out-of-pocket 
expenses (including attorneys' fees and legal expenses of Dorsey & Whitney 
LLP, special counsel for the Lender) incurred in connection with the Loan 
Agreement, including in connection with the negotiation, preparation and 
execution of the Amendment Documents and all other documents negotiated, 
prepared and executed in connection with the Amendment Documents, and in 
enforcing the obligations of the Borrower under the Amendment Documents, and 
to pay and save the Lender harmless from all liability for, any stamp or 
other taxes which may be payable with respect to the execution or delivery of 
the Amendment Documents, which obligations of the Borrowers shall be joint 
and several and shall survive any termination of the Loan Agreement.

     SECTION 10. HEADINGS.  The headings of various sections of this 
Amendment have been inserted for reference only and shall not be deemed to be 
a part of this Amendment,

     SECTION 11. COUNTERPARTS.  The Amendment Documents may be executed in 
several counterparts as deemed necessary or convenient, each of which, when 
so executed, shall be deemed an original provided that all such counterparts 
shall be regarded as one and the same document, and either party to the 
Amendment Documents may execute any such agreement by executing a counterpart 
of such agreement.

     SECTION 11 GOVERNING LAW.  THE AMENDMENT DOCUMENTS SHALL BE 

<PAGE>

GOVERNED BY THE INTERNAL LAWS OF THE STATE OF MINNESOTA, WITHOUT GIVING 
EFFECT TO CONFLICT OF LAW PRINCIPLES THEREOF.      
[REMAINDER OF PAGE INTENTIONALLY LEFT BLANK]

     IN WITNESS WHEREOF, the parties hereto have caused this Amendment to be 
executed as of the date and year first above written.
     
     
BORROWER:                     COGENERATION CORPORATION OF
                              AMERICA, formerly known as NRG
                              Generating (U.S.) Inc.
                    
                    
                              By:       /s/ Timothy P. Hunstad 
                                  --------------------------------
                    
                              Title:         VP & CFO                 
                                  --------------------------------


BORROWER:                     COGENAMERICA FUNDING INC., formerly
                              known as NRGG Funding Inc.


                              By:       /s/ Timothy P. Hunstad        
                                  --------------------------------
                              Title:         VP & CFO                 
                                  --------------------------------


LENDER:                       NRG ENERGY, INC.


                              By:       Brian Bird               
                                  --------------------------------
                              Title:         Treasurer           
                                    ------------------------------

<PAGE>

                                                                  EXHIBIT A-1 TO
                                                                 FIRST AMENDMENT

                                                                       EXHIBIT A

                                                               November 30, 1998

                            AMENDED AND RESTATED NOTE

     FOR VALUE RECEIVED, the undersigned, COGENERATION CORPORATION OF 
AMERICA, formerly known as NRG Generating (U.S.) Inc., a Delaware corporation 
("NRGG"), and CogenAmerica Funding Inc., formerly known as NRGG Funding Inc., 
a Delaware corporation ("Funding"), hereby jointly, severally and 
unconditionally promise to pay to the order of NRG ENERGY, INC. a Delaware 
corporation, or registered assigns (the "Lender"), at the office of the 
Lender at 1221 Nicollet Mall, Suite 700, Minneapolis, MN 53403 or by wire 
transfer in accordance with such instructions as the Lender may require, in 
lawful money of the United States of America and in immediately available 
funds, the principal amount of up to $22,000,000 or, if less, the aggregate 
unpaid principal amount of the Loan made by the Lender pursuant to Section 
2.01 of the Loan Agreement referred to below (in either case, to be paid 
together with any accrued interest not required to be paid currently in 
cash), which sum shall be due and payable in such amounts and on such dates 
as are set forth in the Supplemental Loan Agreement, dated as of December 10, 
1997 among NRGG and Funding (each a "Borrower" and collectively the 
"Borrowers") and the Lender (as the same may be supplemented or amended from 
time to time, the "Loan Agreement"; terms defined therein being used herein 
as so defined). The undersigned further agree to pay interest at said office 
or to such account, in like money, from October 30, 1998 on the unpaid 
principal amount hereof from time to time outstanding at the rates and on the 
dates specified in Section 2.06 of the Loan Agreement.

    All parties now and hereafter liable with respect to this Note, whether 
maker, principal, surety, guarantor, endorser or otherwise, hereby waive 
diligence, presentment, demand, protest and notice of any kind whatsoever. 
The nonexercise of the holder of this Note of any of its rights hereunder in 
any particular instance shall not constitute a waiver thereof in that or any 
subsequent instance.

     This note is the Note referred to in the Loan Agreement, which Loan 
Agreement, among other things, contains provisions for the acceleration of 
the maturity hereof upon the happening of certain events, for optional and 
mandatory prepayment of the principal hereof prior to the maturity hereof and 
for the amendment or waiver of certain provisions of the Loan Agreement, all 
upon the terms and conditions therein specified.

     This Note amends and restates that certain Note of the Borrowers dated 
October 30, 1998 in the principal amount of $8,902,750.59 and evidences 
unpaid principal in such amount and an accrued and unpaid interest thereon.

     This Note shall be construed in accordance with and governed by the laws 
of the State of Minnesota and any applicable laws of the United States of 
America.


<PAGE>

     THIS NOTE MAY NOT BE TRANSFERRED EXCEPT IN COMPLIANCE WITH THE TERMS OF 
THE LOAN AGREEMENT. TRANSFERS OF THIS NOTE MUST BE RECORDED IN THE REGISTER 
MAINTAINED BY THE LENDER PURSUANT TO THE TERMS OF THE LOAN AGREEMENT.

     THIS NOTE IS SUBJECT TO THE SUBORDINATION AGREEMENT, DATED AS OF 
DECEMBER 10,1997, AMONG NRGG, THE LENDER AND MEESPIERSON CAPITAL CORP., UNDER 
WHICH THIS NOTE AND NRGG'S OBLIGATIONS HEREUNDER ARE SUBORDINATED IN THE 
MANNER SET FORTH THEREIN TO THE PRIOR PAYMENT OF CERTAIN OBLIGATIONS TO THE 
HOLDERS OF SENIOR INDEBTEDNESS AS DEFINED THEREIN.

     THIS NOTE IS FURTHER SUBJECT TO THE SUBORDINATION PROVISIONS SET FOR THE 
IN THE SUBORDINATION AGREEMENT, DATED AS OF DECEMBER 10, 1997, BETWEEN THE 
LENDER AND THE CHASE MANHATTAN BANK IN ITS CAPACITY AS COLLATERAL AGENT. A 
COPY OF THAT SUBORDINATION AGREEMENT IS ON FILE WITH NRGG, FUNDING AND 
COGENAMERICA MORRIS INC., FORMERLY KNOWN AS NRG MORRIS INC., AND IS AVAILABLE 
FOR INSPECTION AT THEIR RESPECTIVE OFFICES.

                              COGENERATION CORPORATION OF AMERICA



                              -------------------------------------------
                              Timothy P. Hunstad
                              Vice President and Chief Financial Officer


                              COGENAMERICA FUNDING INC.



                              -------------------------------------------
                              Timothy P. Hunstad
                              Vice President and Chief Financial Officer

<PAGE>

                                                                    EXHIBIT B TO
                                                                 FIRST AMENDMENT


                              MATTERS TO BE COVERED BY
                                 OPINION OF COUNSEL
                                  TO THE BORROWERS


     The opinion of counsel to the Borrowers and to NRG Morris Inc. (the 
Borrowers and NRG Morris Inc. from time to time being referred to, 
collectively, as the  "Loan Parties") and which is called for by Article 3 of 
the Supplemental Loan Agreement, as amended by the First Amendment to Loan 
Agreement dated November 30, 1998 (as amended, the "Loan Agreement") shall be 
addressed to the Lender and dated the date upon which all other conditions to 
effectiveness of the First Amendment to Loan Agreement are satisfied. It 
shall be satisfactory in form and substance to the  Lender and shall cover 
the matters set forth below, subject to such assumptions, exceptions and 
qualifications as may be acceptable to the Lender and counsel to the Lender.  
For purposes of the opinion of counsel the term "Transaction Documents" shall 
mean the Loan Agreement, the Amended and Restated Note of the Borrowers dated 
November 30, 1998 in the principal amount of $22,000,000, the Pledge 
Agreement (as such term and other capitalized terms used herein and not 
otherwise defined herein are defined in the Loan Agreement), the Security 
Documents and all agreements, instruments and documents executed and 
delivered by the Borrowers or either of them in connection with the Loan 
Agreement, the Equity Commitment Guaranty dated as of December 10, 1997 made 
by NRGG in favor of the Lender and the Assignment and Assumption Agreement 
dated as of December 10, 1997 between the Lender and Funding.

     (i)    Each Loan Party is a corporation duly incorporated and validly 
existing and in good standing under the laws of the State of Delaware and has 
and had at the time of entry into the Transaction Documents all requisite 
corporate power and authority to carry on its business as now conducted, to 
enter into the Transaction Documents executed by it and to perform all of its 
obligations under each and all of the foregoing.  Each Loan Party is duly 
qualified and in good standing as a corporation in the State of Delaware and 
as a foreign corporation in all of the jurisdictions in which the character 
of the properties owned or leased by it or the business conducted by it makes 
such qualification necessary and the failure to so qualify would permanently 
preclude the Borrower from enforcing its rights with respect to any material 
asset or expose the Borrower to material liability.  

     (ii)   The execution, delivery and performance by each Loan Party of the 
Transaction Documents have been duly authorized by all necessary corporate 
action by such Loan Party.

     (iii)  The Transaction Documents constitute the legal, valid and binding 
obligations of each Loan Party executing the same, enforceable against such 
Loan Party in accordance with their respective terms.

     (iv)   The execution, delivery and performance by each Loan Party of the 
Transaction Documents executed by it did not and will not (i) violate any 
provision of any law, statute, rule or regulation or, to the best knowledge 
of such counsel, any order, writ judgment, injunction, decree, determination 
or award of any court, governmental agency or arbitrator presently in effect 
having applicability to such Loan Party, (ii) violate or contravene any 
provision of the 

<PAGE>


Certificate of Incorporation or bylaws of such Loan Party, or (iii) result in 
a breach of or constitute a default under any indenture, loan or credit 
agreement or any other agreement lease or instrument known to such counsel to 
which such Loan Party is a party or by which it or any of its properties may 
be bound or result in the creation of any Lien thereunder.

     (v)    No order, consent, approval, license, authorization or validation 
of, or filing, recording or registration with, or exemption by, any 
governmental or public body or authority was or is required on the part of 
any Loan Party to authorize, or was or is required in connection with the 
execution, delivery either performance of, or the legality, validity, binding 
effect or enforceability of, the Transaction Documents, except for any 
necessary filing or recordation of or with respect to any of the Security 
Documents.

     (vi)   The best knowledge of such counsel, there are no actions, suits 
or proceedings pending or threatened against or affecting any Loan Party or 
any of its properties before any court or arbitrator, or any governmental 
department, board, agency or other instrumentality which (i) challenge the 
legality, validity or enforceability of the Transaction Documents, or (ii) if 
determined adversely to a Loan Party, would have a material adverse effect on 
the business, operations, property or condition (financial or otherwise) of 
such Loan Party and its Subsidiaries as a consolidated enterprise or on the 
ability of such Loan Party to perform its obligations under the Transaction 
Documents.

     (vii)  The Pledge Agreement creates the lien it purports to create upon 
the properties and interests specifically described therein. The descriptions 
of properties and interests in the Security Documents and any related 
financing statements are adequate for the purpose of such instruments and for 
perfection of the liens of the Lender. The filing of the Uniform Commercial 
Code financing statements executed by Funding and by NRG Morris Inc. and 
filed in [describe filing office] on [state dates of filings] perfected the 
Liens created under the Pledge Agreement and such Liens continue to be 
perfected on the date hereof.