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                                                 Exhibit 10.27.15





                         FIRST AMENDMENT
                               to
               OPERATION AND MAINTENANCE AGREEMENT

     This FIRST AMENDMENT to OPERATION AND MAINTENANCE AGREEMENT
is entered into as of December 10, 1997 by and between NRG
(Morris) Cogen, LLC, a Delaware limited liability company (the
"Owner") and NRG Morris Operations Inc. (the "Operator").

     WHEREAS, Owner and Operator are parties to that certain
Operation and Maintenance Agreement dated as of September 19,
1997 (the "O&M Agreement");

     WHEREAS, Owner and Operator wish to amend the O&M Agreement
as herein provided;

        NOW, THEREFORE, Owner and Operator hereby agree as
follows:

     1.   The definition of the term "Agent" in Article I of the
O&M Agreement shall be deleted in its entirety and the following
shall be substituted therefor:

     "Agent" means any agent appointed by the Lender(s) under the
Financing Agreements.

     2.   Section 4.1.16 of the O&M Agreement shall be amended by
adding the following sentences to the end thereof:

     Owner  shall  have  the right upon 30 days'  written  notice
documenting  the  basis for such action, to require  Operator  to
remove  for  cause  the  person selected as  the  Plant  Manager,
subject  to an Operator's 30-day cure period (but absent  such  a
cure,  Operator  will  remove  such  person  from  such  position
following such a request by Owner).  As soon as practicable after
any  such  removal,  Operator shall appoint a new  Plant  Manager
after  first  obtaining Owner's consent to such new  appointment.
Owner will not exercise its right to require such removal in  any
manner  that  causes Operator to violate applicable  labor  laws,
based on a written opinion of outside counsel of the Operator.

     3.    Section 4.2.9 of the O&M Agreement shall be amended by
adding the following to the end thereof:


     Operator and Owner shall cooperate to maximize excess energy
sales and manage plant operating margins.  Owner and Operator
shall work to agree to a detailed plan to accomplish such
objectives prior to Commercial Operation.

     4.   Section 10.1 of the O&M Agreement shall be deleted in
its entirety and the following shall be substituted therefor:

               10.1 Insurance Requirements of Operator.  Unless
     Owner shall advise Operator that Owner has satisfied the
     following requirements in whole or in part by naming
     Operator as a named insured on Owner's insurance policies,
     Operator shall procure and maintain in full force and effect
     at all times  that the Project is being operated (and, in
     any event, no later than the date on which Operator has
     employees at the Project), insurance policies with limits
     and coverage provisions in no event less than the limits and
     coverage provisions set forth below.

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          10.1.1    General Liability Insurance:  Liability
          insurance on an occurrence basis against claims for
          personal injury (including bodily injury and death) and
          property damage.  Such insurance shall provide coverage
          for products-completed operations, blanket contractual,
          explosion, collapse and underground coverage, broad
          form property damage, personal injury insurance,
          independent contractors and the hostile fire exception
          to the pollution liability exclusion with a $1,000,000
          minimum limit per occurrence for combined bodily injury
          and property damage; provided that the policy general
          aggregate, if any, shall apply separately to the
          Project.  A maximum deductible or self-insured
          retention of $500,000 per occurrence shall be allowed.

          10.1.2    Automobile Liability Insurance: Automobile
          liability insurance against claims for personal injury
          (including bodily injury and death) or property damage
          arising out of the use of all owned, leased, non-owned
          and hired motor vehicles including loading and
          unloading with a $1,000,000 minimum limit per
          occurrence for combined bodily injury and property
          damage and containing appropriate no-fault insurance
          provisions where applicable.  A maximum deductible or
          self-insured retention of $500,000 per occurrence shall
          be allowed.

          10.1.3    Workers' Compensation Insurance: Workers'
          compensation insurance as required by applicable Legal
          and Contractual Requirements.  A maximum deductible or
          self-insured retention of $500,000 per occurrence shall
          be allowed.

          10.1.4    Employer's Liability Insurance: Employer's
          liability insurance for all employees of the Operator
          with a $1,000,000 minimum limit per accident.  A
          maximum deductible or self-insured retention of
          $500,000 shall be allowed.

          10.1.5    Excess Insurance: Excess liability insurance
          on an occurrence basis (or modified AEGIS claims made
          form) covering claims in excess of the underlying
          insurance described in Sections 10.1.1, 10.1.2 and
          10.1.4 hereof with a $10,000,000 minimum limit per
          occurrence; provided, that the general aggregate limit
          of liability, if any, shall apply separately to the
          Project.

          10.1.6    Aircraft Insurance: If the performance of
          Operator's obligations under this Agreement requires
          the use of any aircraft that is owned, leased or
          chartered by Operator, aircraft liability insurance
          with a $25,000,000 minimum limit per occurrence for
          property damage and bodily injury, including passengers
          and crew.

All policies of liability insurance to be maintained by Operator
shall be endorsed (a) to provide a severability of interests or
cross liability clause; (b) to name Owner, the Agent and their
respective directors, officers, employees and agents as
additional insureds; and (c) to provide that the insurance shall
be primary and not excess to or contributing with any insurance
or self-insurance maintained by Owner or the Lenders.

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     5.   Section 12.4 of the O&M Agreement shall be deleted in
its entirety and the following shall be substituted therefor:

          12.4 Certain Remedies of Owner and Millennium for
     Selected Operator Defaults.  In addition to the remedies set
     out in Section12.3, Owner shall have the right to terminate
     this Agreement, without resort to the arbitration procedures
     set out in Article XIII, if (a) Operator is in default under
     Section12.2.3 or Section 12.2.7 hereof, (b) Operator is in
     default a second time under Section 12.2.8 hereof, (c) the
     heat rate of the Project for any Operating Year is greater
     than three percent (3%) above the Guaranteed Heat Rate for
     such Operating Year, (d) the Owner is required to pay more
     than one million five hundred thousand dollars ($1,500,000)
     in Operator Standby Power Costs in any Operating Year;
     provided, that Operator may cure a default under Section
     12.4(d) by paying to Owner an amount equal to the entire
     amount of the excess of such Operator Standby Power Costs
     over one million five hundred thousand dollars ($1,500,000);
     provided further, that Operator may not cure any such
     default if the amount of such Operator Standby Power Costs
     exceeds one million nine hundred thousand dollars
     ($1,900,000) , or (e) NRG Energy, Inc. ("NRG Energy")
     directly or indirectly owns less than ten percent (10%) of
     the outstanding common stock (the "Stock") of NRG Generating
     (U.S.), Inc. ("NRGG") as a result of a sale of Stock by NRG;
     provided, that, if it has not been previously exercised,
     Owner's right to exercise its termination rights under this
     Section 12.4(e) shall be suspended for no more than 180 days
     during any period in which NRG Energy is, directly or
     indirectly, reaquiring an aggregate amount of Stock equal to
     or in excess of ten percent (10%) of the Stock.  Upon any
     such termination, Operator shall turn over to Owner care,
     custody and control of the Project and the Leased Equipment,
     and shall assign such subcontracts for services provided
     hereunder as Owner may request.  Operator shall also turn
     over all spare parts and other consumables in the inventory.
     Operator shall cooperate with Owner and any replacement
     operator in a transition of operation and maintenance
     responsibilities.  In addition, in the event that Operator
     fails to deliver Steam to Millennium pursuant to the
     requirements of the ESA, Millennium shall have the right to
     immediately re-assume operating control of the Leased
     Equipment without affording Operator a cure period, pending
     the outcome of any arbitration proceedings under Article27
     of the ESA.  Operator will cooperate with Millennium during
     any such period, and shall only be entitled to re-assume
     operating control of the Leased Equipment once Owner and
     Millennium are satisfied that Operator can meet its
     responsibilities under this Agreement.  During any period in
     which Millennium has assumed operating control of the Leased
     Equipment, the Annual Fee to be paid to Operator shall be
     reduced by twenty-five percent (25%) and Operator shall not
     be entitled to any bonus under Section 8.4.

     6.   To the extent Operator had in effect insurances meeting
the requirements set forth above in Section 4 of this Amendment,
Owner hereby waives any failure by Operator to meet the
requirements of Section 10.1 of the O&M Agreement prior to the
date hereof.

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     7.   This Amendment is limited as specified and shall not
constitute a modification, acceptance or waiver of any other
provision of the O&M Agreement or any other agreement referred to
therein, or prejudice any right or rights which Owner or Operator
may now have or may have in the future under or in connection
with the O&M Agreement.  Except as expressly modified hereby, the
terms and provisions of the O&M Agreement shall continue in full
force and effect.  All references to the O&M  Agreement shall
hereafter be deemed to refer to the O&M Agreement as modified
hereby.

     8.   This Amendment may be executed in separate counterparts
by  Owner  and  Operator,  each of which  when  so  executed  and
delivered shall be an original, but all of which shall constitute
one  and  the  same instrument.  A complete set  of  counterparts
shall be delivered to each of Owner and Operator.


      9.    THIS AMENDMENT AND THE RIGHTS AND OBLIGATIONS OF  THE
PARTIES  HEREUNDER  SHALL BE CONSTRUED  IN  ACCORDANCE  WITH  AND
GOVERNED BY THE LAW OF THE STATE OF ILLINOIS, BUT WITHOUT  GIVING
EFFECT TO.CONFLICTS OF LAW PROVISIONS.


      10.  This Amendment shall become effective on the date when
the  Agent  has consented in writing to the execution  hereof  by
Owner pursuant to the terms of the Financing Agreements.


     IN WITNESS WHEREOF, Owner and Operator have caused their
duly authorized representatives to execute and deliver this
Amendment as of the date first above written.


                              NRG (MORRIS) COGEN, LLC



                              By /s/ Craig Mataczynski
                                 Name: Craig Mataczynski
                                 Title: President



                              NRG MORRIS OPERATIONS INC.


                              By Ronald J. Will
                                 Name: Ronald J. Will
                                 Title: President