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UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
WASHINGTON, D.C. 20549

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SCHEDULE 13D/A
(RULE 13d-101)

UNDER THE SECURITIES EXCHANGE ACT OF 1934
AMENDMENT NO. 8

COGENERATION CORPORATION OF AMERICA
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(Name of Issuer)

Common Stock, par value $.01 per share
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(Title of Class of Securities)

628950 10 7
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(CUSIP number)

James J. Bender                         John P. Moore, Jr.
Vice President and General Counsel              Corporate Secretary
NRG Energy, Inc.                  Northern States Power Company
1221 Nicollet Mall, Suite 700           414 Nicollet Mall, Fourth Floor
Minneapolis, MN 55403                    Minneapolis, MN 55401
(612) 373-5300                           (612) 330-5500
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(Name, address and telephone number of person
authorized to receive notices and communications)

October 30, 1998
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(Date of event which requires filing of this statement)

If the filing person has previously filed a statement on Schedule 13G
to report the acquisition which is the subject of this Schedule 13D, and is
filing this schedule because of Rule 13d-1(b)(3) or (4), check the following box
/ /.

Note. Six copies of this statement, including all exhibits, should be
filed with the Commission. See Rule 13d-1(a) for other parties to whom copies
are to be sent.

*The remainder of this cover page shall be filled out for a reporting
person's initial filing on this form with respect to the subject class of
securities, and for any subsequent amendment containing information which would
alter disclosures provided in a prior cover page.

The information required on the remainder of this cover page shall not
be deemed to be "filed" for the purpose of Section 18 of the Securities Exchange
Act of 1934 ("Act") or otherwise subject to the liabilities of that section of
the Act but shall be subject to all other provisions of the Act (however, see
the Notes).

(Page 1 of 4)

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Item 4 of Schedule 13D is hereby amended and restated as follows:

ITEM 4.  PURPOSE OF TRANSACTION

NRG Energy, Inc. ("NRG") acquired a 41.86% interest in Cogeneration
Corporation of America (formerly named "NRG Generating (U.S.) Inc." and "O'Brien
Environmental Energy, Inc.") (the "Company") pursuant to the Composite Fourth
Amended and Restated Plan of Reorganization (the "Plan") for O'Brien
Environmental Energy, Inc., confirmed by order of the United States Bankruptcy
Court for the District of New Jersey under Chapter 11 of the United States
Bankruptcy Code on February 22, 1996, and pursuant to the Amended and Restated
Stock Purchase and Reorganization Agreement dated as of January 31, 1996 (the
"Purchase Agreement"). Copies of the Plan and the Purchase Agreement were filed
as exhibits to Schedule 13D filed by NRG on May 10, 1996.

In connection with the negotiation and consummation of the Plan, on
March 8, 1996, NRG entered into a loan agreement (the "Loan Agreement") with
O'Brien (Schuylkill) Cogeneration, Inc. ("Schuylkill"), a wholly owned
subsidiary of the Company, pursuant to which NRG agreed to make a loan in the
principal amount of $10,000,000 available to Schuylkill upon Schuylkill's
request. As part of the consideration for entering into the Loan Agreement, the
Company entered into an option agreement dated March 8, 1996 (the "Option
Agreement") with NRG. Pursuant to the Option Agreement, the Company agreed that,
on the date on which NRG made a loan to Schuylkill pursuant to the Loan
Agreement, NRG would have the right, upon 15 business days' notice, to reduce
the outstanding principal amount of the note payable to NRG by Schuylkill by
$3,000,000 in exchange for the 396,255 shares (the "Conversion Shares") of the
Company's common stock, par value $0.01 per share (the "Common Stock").

In June 1997, NRG agreed to allow Schuylkill to borrow funds under the
Loan Agreement on an "as needed" basis rather than requiring that Schuylkill
borrow the full $10,000,000 on the funding date. On August 22, 1997, NRG made a
loan of $2,700,000 to Schuylkill pursuant to the Loan Agreement, bringing the
total outstanding principal amount under the Loan Agreement to $4,500,000 and
thereby vesting in NRG an option, exercisable on 15 business days' notice to the
Company, to acquire the Conversion Shares. On August 28, 1997, NRG notified the
Company of its intention to exercise its option to acquire the Conversion Shares
(the "Exercise Notice"). On November 25, 1997, NRG acquired the Conversion
Shares. Copies of the Option Agreement and the Exercise Notice were filed as
exhibits to Amendment No. 1 to Schedule 13D filed by NRG on August 29, 1997.

On August 3, 1998, NRG received an irrevocable proxy (the "Proxy")
granting it the right for a limited period of time to vote 147,676 shares of
Common Stock. NRG obtained the Proxy in order to increase its voting control
over the Company. A copy of the Form of Proxy was filed as an exhibit to
Amendment No. 4 to Schedule 13D filed by NRG on August 3, 1998. As a result of
its receipt of the Proxy, NRG now beneficially owns an aggregate of 3,254,288,
or 47.60%, of the Common Stock.

On September 14, 1998, NRG sent a letter to the Company's Chairman
requesting that he call a special meeting of the Company's shareholders to
consider the removal of Robert Sherman from the Company's Board of Directors.
NRG also filed definitive solicitation materials with the Securities and
Exchange Commission pursuant to Section 14(a) of the Securities Exchange Act of
1934, as amended, relating to a proposed solicitation of proxies and consents
from the Company's stockholders to remove Mr. Sherman from the Company's Board.
A copy of this letter was filed as an exhibit to Amendment No. 6 to Schedule
13D filed by NRG on October 15, 1998.  On October 26, 1998, consents of over 50%
of the Company's shareholders in favor of Mr. Sherman's removal from the
Company's Board of Directors were filed with the Company and Mr. Sherman was
removed from the Board of Directors.

(Page 2 of 4)

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On October 27, 1998 the resulting vacancy was filled with Michael
O'Sullivan, who is Vice President of NRG's North American division, resulting in
five of the Company's eight directors now being employees of NRG. On the same
day, Mr. Sherman's employment agreement with the Company was terminated for
cause and Ms. Julie A. Jorgensen, senior counsel of NRG and a director of the
Company, was elected as the Company's interim president and chief executive
officer. Also on October 27, 1998, NRG entered into a letter agreement with
Wexford Management LLC, a holder of approximately 6.4% of the outstanding Common
Stock. A copy of this agreement was filed as an exhibit to Amendment No. 7 to 
Schedule 13D filed by NRG on October 30, 1998.

On October 30, 1998, NRG entered into a letter agreement with Rumpere 
Capital, a holder of approximately 3.2% of the outstanding Common Stock.  This 
agreement is attached as Exhibit 8 to Schedule 13D, and its terms are hereby 
incorporated by reference in answer to this Item.

NRG intends to review its investment in the Company on a continuing
basis and may, at any time, consistent with NRG's obligations under the federal
securities laws and the Company's Certificate of Incorporation, determine to
increase or decrease its ownership of shares of the Common Stock through
purchases or sales of the Common Stock in the open market or in privately
negotiated transactions. NRG's review of its investment in the Company will
depend on various factors, including the Company's business prospects, other
developments concerning the Company, general economic conditions, money and
stock market conditions, and any other facts and circumstances that may become
known to NRG regarding its investment in the Company. At the time of filing this
Amendment No. 8, NRG has no plans to purchase additional shares of Common Stock
in the open market or in privately negotiated transactions.

Except as described in this Item 4, NRG has no present plans or
proposals which relate to or would result in (i) an extraordinary corporate
transaction, such as a merger, reorganization or liquidation, involving the
Company or any of its subsidiaries, (ii) a sale or transfer of a material amount
of assets of the Company or any of its subsidiaries, (iii) any change in the
board of directors or management of the Company or any of its subsidiaries, (iv)
any material change in the present capitalization or dividend policy of the
Company, (v) any other material change in the Company's business or corporate
structure; (vi) changes in the Company's charter or bylaws or other actions
which may impede the acquisition of control of the Company by any person, (vii)
causing a class of securities of the Company to be delisted from a national
securities exchange or cease to be quoted in an inter-dealer quotation system of
a registered national securities association, (viii) a class of equity
securities of the Company becoming eligible for termination of registration
pursuant to Section 12(g)(4) of the Securities Exchange Act of 1934 or (ix) any
action similar to any of those described above. However, NRG retains its rights
to modify its plans with respect to the transactions described in this Item 4,
to acquire or dispose of securities of the Company and to formulate plans and
proposals that could result in the occurrence of any such events, subject to
applicable laws and regulations.

* * *

Item 7 of Schedule 13D is hereby amended and restated as follows:

ITEM 7.  MATERIAL TO BE FILED AS EXHIBITS

1.       Composite Fourth Amended and Restated Plan of Reorganization
for O'Brien Environmental Energy, Inc. (previously filed as an
exhibit to NRG's Schedule 13D on May 10, 1996).

2.       Amended and Restated Stock Purchase and Reorganization
Agreement, dated as of January 31, 1996, between NRG Energy,
Inc. and O'Brien Environmental Energy, Inc. (previously filed
as an exhibit to NRG's Schedule 13D on May 10, 1996).

3.       Option Agreement, dated March 8, 1996, between O'Brien
Environmental Energy, Inc. and NRG Energy, Inc. (previously
filed as an exhibit to Amendment No. 1 to NRG's Schedule 13D
on August 29, 1997).

4.       Option Exercise Notice, dated August 28, 1997, from NRG
Energy, Inc. to NRG Generating (U.S.), Inc. (previously filed
as an exhibit to Amendment No. 1 to NRG's Schedule 13D on
August 29, 1997).

5.       Form of Proxy to be executed by Halcyon Alchemy Fund, L.P.,
Halcyon Special Situations, L.P., Gryphon Hidden Values
Limited and Gryphon Hidden Values II Limited (previously filed
as an exhibit to Amendment No. 4 to NRG's Schedule 13D on
August 3, 1998).

6.       Letter, dated September 14, 1998, from NRG Energy, Inc. to
David H. Peterson, Chairman of the Board of Directors of
Cogeneration Corporation of America (previously filed as an
exhibit to Amendment No. 5 to NRG's Schedule 13D on October
15, 1998).

7.       Letter Agreement, dated October 27, 1998, between NRG and
Wexford Management LLC (previously filed as an exhibit to 
Amendment No. 7 to NRG's Schedule 13D on October 30, 1998).

8.       Letter Agreement, dated October 30, 1998, between NRG and 
Rumpere Capital.

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SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I
certify that the information set forth in this statement is true, complete and
correct.

NRG ENERGY, INC.

Dated:  November 3, 1998           /s/ James J. Bender
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Name:  James J. Bender
Title:  Vice President and General Counsel

NORTHERN STATES POWER COMPANY

/s/ John P. Moore, Jr.
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Name:  John P. Moore, Jr.
Title:  Corporate Secretary

(Page 4 of 4)

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[NRG ENERGY LETTERHEAD]

October 30, 1998

VIA FACSIMILE (212-223-8922)

Peter M. Faulkner
Rumpere Capital
767 Third Avenue, 5th Floor
New York, NY  10017

Re: Cogeneration Corp. of America

Dear Peter:

I am writing to set forth the terms of the agreement between Rumpere Capital
("Rumpere") and NRG Energy, Inc. ("NRG") with respect to certain matters
concerning Cogeneration Corporation of America ("CCA").

1.   Rumpere Capital, L.P. and Rumpere Capital Fund, Ltd. own collectively
222,000 shares of stock of CCA (the "Rumpere Shares").

2.   NRG holds approximately 3,106,612 shares of stock of CCA. NRG has five
nominees (the "NRG Directors") serving as members of the board of directors
of CCA. NRG and/or the NRG Directors are participants in a proxy
solicitation relating to CCA (the "Proxy Solicitation").

3.   Rumpere has agreed to provide NRG with proxies and consents with respect
to the Rumpere Shares solely for purposes of voting in connection with the
Proxy Solicitation. The parties agree that Rumpere's grant of such proxies
and consents shall be irrevCCAble, subject to the limitations set forth
herein on the use of such proxies and consents, until November 30, 1998. 
The parties further agree that NRG's ability to utilize the proxies and
consents shall terminate and NRG shall have no right to vote the Rumpere
Shares in connection with the Proxy Solicitation (a) after the conclusion 
of the CCA

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Peter M. Faulkner
October 30, 1998
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shareholders' meeting scheduled for November 12, 1998 or any postponement
or adjournment thereof, but in no event after November 30, 1998 or (b) on
such earlier date that NRG or the NRG Directors agrees (i) to a severance
or other arrangement with Robert Sherman that provides him with
compensation or other consideration in excess of the amounts set forth in
his employment agreement dated March 28, 1997, or (ii) to the payment by
CCA in excess of an aggregate amount of $250,000 of the costs and expenses
of the law firms, a public relations firm and printer retained by Robert
Sherman and /or CCA in respect of the Proxy Solicitation.  Concurrently
herewith Rumpere is delivering executed proxy cards and consents with
respect to the Proxy Solicitation, the use of which shall be subject to the
terms and conditions set forth above.

If this agreement accurately reflects our understanding, please execute and 
return a copy of this letter to the undersigned.

Sincerely,

/s/ Craig Mataczynski

ACCEPTED & AGREED
this 30th day of October, 1998

Rumpere Capital

By:  Peter M. Faulkner
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Name: Peter M. Faulkner
Title: Portfolio Manager