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                                                                     Exhibit 4.9

                                 GUARANTOR NOTE

US$800,000,000                                                    March 30, 2000

            For value received, the undersigned, LOUISIANA GENERATING LLC, a
Delaware limited liability company (the "Subsidiary Guarantor"), by this
promissory note promises to pay to the order of NRG SOUTH CENTRAL GENERATING
LLC, a Delaware limited liability company ("the Issuer"), at the office of The
Chase Manhattan Bank, a bank organized and existing under the laws of the State
of New York, located at 450 West 33rd Street, 15th Floor, New York, NY 10001, in
lawful currency of the United States of America and in immediately available
funds, the principal amount of eight hundred million dollars (US$800,000,000),
or if less, the aggregate unpaid and outstanding principal amount of this
Guarantor Note advanced by the Issuer to the Subsidiary Guarantor pursuant to
that certain Guarantor Loan Agreement, dated as of March 30, 2000 (the
"Guarantor Loan Agreement"), by and among the Subsidiary Guarantor and the
Issuer, and as the same may be amended from time to time, and all other amounts
owed by the Subsidiary Guarantor to the Issuer hereunder.

            This is one of the Guarantor Notes entered into pursuant to the
Guarantor Loan Agreement and is entitled to the benefits thereof and is subject
to all terms, provisions and conditions thereof. Capitalized terms used and not
defined herein shall have the meanings set forth in Appendix A of that certain
Trust Indenture, dated as of March 30, 2000 (the "Indenture"), by and between
the Issuer and The Chase Manhattan Bank, a bank organized and existing under the
laws of the State of New York, as Bond Trustee.

            Reference is hereby made to the Indenture and the Security Documents
for the provisions, among others, with respect to the custody and application of
the Collateral, the nature and extent of the security provided thereunder, the
rights, duties and obligations of the Subsidiary Guarantor and the rights of the
holder of this Guarantor Note.

            The principal amount hereof is payable in accordance with the
Guarantor Loan Agreement, and such principal amount may be prepaid solely in
accordance with the Guarantor Loan Agreement.

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            The Subsidiary Guarantor further agrees to pay, in lawful currency
of the United States of America and in immediately available funds, interest
from the date hereof on the unpaid and outstanding principal amount hereof until
such unpaid and outstanding principal amount shall become due and payable
(whether at stated maturity, by acceleration or otherwise) at the rates of
interest and at the times set forth in the Guarantor Loan Agreement, and the
Subsidiary Guarantor agrees to pay all other amounts due, including, without
limitation, fees and costs, as stated in the Guarantor Loan Agreement.

            Upon the occurrence of any one or more Guarantor Events of Default
(as defined in Section 4.1 of the Guarantor Loan Agreement) all amounts then
remaining unpaid under this Guarantor Note may become or be declared to be
immediately due and payable as provided in the Guarantor Loan Agreement, without
notice of default, presentment or demand for payment, protest or notice of
nonpayment or dishonor, or notices or demands of any kind, all of which are
expressly waived by the Subsidiary Guarantor.

            The obligations hereunder are subject to the limitations set forth
in Section 5.10 of the Guarantor Loan Agreement, the provisions of which are
hereby incorporated by reference.

            THIS GUARANTOR NOTE IS A CONTRACT MADE UNDER THE LAWS OF THE STATE
OF NEW YORK OF THE UNITED STATES OF AMERICA AND SHALL FOR ALL PURPOSES BE
GOVERNED BY AND CONSTRUED IN ACCORDANCE WITH THE LAWS OF SUCH STATE WITHOUT
REGARD TO THE CONFLICT OF LAW RULES THEREOF (OTHER THAN SECTION 5-1401 OF THE
NEW YORK GENERAL OBLIGATIONS LAW).


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            IN WITNESS WHEREOF, the Subsidiary Guarantor has caused this
Guarantor Note to be duly executed.

                                        LOUISIANA GENERATING LLC


                                        By: /s/ Craig A. Mataczynski
                                            ------------------------------------
                                                Name:  Craig A. Mataczynski
                                                Title: Vice President


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