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                                                                   EXHIBIT 99.31



                               EIGHTH AMENDMENT TO

                            1988 AMENDED AND RESTATED

                       NUCLEAR FUEL HEAT PURCHASE CONTRACT

                  Eighth Amendment, dated as of August 26, 1999 (this "Eighth
Amendment"), to the 1988 Amended and Restated Nuclear Fuel Heat Purchase
Contract dated as of October 4, 1988, as amended by First, Second, Third,
Fourth, Fifth and Sixth Amendments thereto dated as of February 1, 1990,
September 1, 1993, August 31, 1994, March 8, 1996, August 29, 1996, August 28,
1997 and August 27, 1998, respectively (as so amended, the "Contract"), between
RENAISSANCE ENERGY COMPANY, a Delaware corporation ("Fuel Company") and THE
DETROIT EDISON COMPANY, a Michigan corporation ("Utility").

                              W I T N E S S E T H:

                  Whereas, the Fuel Company is a party to (i) a $200,000,000 364
Day Credit Agreement dated as of September 1, 1993, as amended by a First
Amendment thereto dated as of September 1, 1994, extension letters from the
Banks to the Fuel Company dated June 30, 1995, a Third Amendment thereto dated
March 8, 1996, a Fourth Amendment thereto dated August 29, 1996, a Fifth
Amendment thereto dated August 28, 1997, and a Sixth Amendment thereto dated
August 27, 1998 among the Fuel Company, the Utility, Barclays Bank PLC, New York
Branch, as agent (the "Agent") and the banks signatory thereto (the "Banks") (as
so amended, the "364 Day Credit Agreement"); and (ii) a $200,000,000 Multi-Year
Credit Agreement dated as of September 1, 1993, as amended by a First Amendment
thereto dated as of September 1, 1994, extension letters from the Banks to the
Fuel Company dated June 30, 1995, a Third Amendment thereto, dated March 8,
1996, a Fourth Amendment thereto, dated September 1, 1996, and a Fifth Amendment
thereto dated September 1, 1997 among the Fuel Company, the Utility, the Agent
and the Banks;

                  Whereas, the 364 Day Credit Agreement is being amended by a
Seventh Amendment thereto (collectively, the "Credit Agreement Amendment");

                  Whereas, it is a condition precedent to the effectiveness of
the Credit Agreement Amendment that the Utility and Fuel Company enter into this
Eighth Amendment.

                  NOW, THEREFORE, in consideration of the mutual covenants and
agreements hereinafter set forth, the Fuel Company and the Utility agree as
follows:

                  Section 1.   Defined Terms. All capitalized terms used herein
and not

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defined shall have the meanings ascribed to such terms in the Contract.

                  Section 2.   Amendments to Contract. Section 2(b) of the
Contract is hereby amended to read in its entirety as follows:

                           "(b) The term of this Contract shall, unless sooner
terminated pursuant to the provisions hereof, end at 12:00 midnight, New York
time, on the Expiration Date. The Expiration Date in effect on the date hereof
is August 25, 2000 Subject to the proviso below, the Utility shall have the
right to renew this Contract for subsequent terms by designating in writing to
the Fuel Company, within 90 days prior to the then current Expiration Date, a
new Expiration Date; provided, however, that the Expiration Date for such
renewal term shall be, (i) in the event the Michigan Public Service Commission
(the "MPSC") has authorized this Contract, not later than September 1, 2003 (an
"Outside Expiration Date") or (ii) if the MPSC has not authorized this Contract,
not later than the earlier to occur of the Outside Expiration Date and twelve
months from the then current Expiration Date; and provided, further, that (i) no
material adverse change shall have occurred (except such as may have occurred in
the ordinary course of the Utility's business) in the financial condition or
results of operations of Utility since the most recent financial statements of
the Utility delivered to the Borrower, and (ii) no Event of Default (as defined
herein or as defined in any Credit Agreement) or other event which with the
giving of notice or lapse of time, or both, would constitute such an Event of
Default shall have occurred and be continuing."

                  Section 3.   Miscellaneous.

                           (a) Each of Utility and Fuel Company hereby
represents and warrants as to itself that this Eighth Amendment has been duly
authorized by all necessary corporate action on its part and this Eighth
Amendment has been duly and validly executed and delivered by itself and
constitutes its respective legal, valid and binding obligation, enforceable in
accordance with the terms of this Eighth Amendment.

                           (b) Except as amended hereby, the terms of the
Contract shall continue in full force and effect and is hereby ratified and
confirmed in all respects as so amended.

                           (c) This Eighth Amendment shall be governed by and
construed in accordance with the laws of the State of New York without reference
to principles of conflicts of laws.

                           (d) This Eighth Amendment may be signed in any number
of counterparts with the same effect as if the signatures thereto and hereto
were upon the same instrument.

                  IN WITNESS WHEREOF, Utility and Fuel Company have caused this
Eighth Amendment to be duly executed by their duly authorized officers, all as
of the day and year first above written.

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                                        RENAISSANCE ENERGY COMPANY



                                        By:
                                           ---------------------------
                                          Dwight Jenkins
                                          Vice President



                                        THE DETROIT EDISON COMPANY



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



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