EXHIBIT 5.1


                 [Orrick, Herrington & Sutcliffe LLP Letterhead]


                                                             August 4, 1998


ESI Tractebel Acquisition Corp.
Northeast Energy, LP
11760 US Highway One
Suite 600
North Palm Beach, Florida  33408

                  Re:  ESI Tractebel Acquisition Corp.
                       Northeast Energy, LP
                       Exchange Offer Registration Statement on Form S-4

Ladies and Gentlemen:

         We have acted as counsel for ESI Tractebel Acquisition Corp., a
Delaware corporation (the "Company") and Northeast Energy, LP, a Delaware
limited partnership (the "Guarantor") in connection with the filing by the
Company and the Guarantor with the Securities and Exchange Commission (the
"Commission") pursuant to the Securities Act of 1933, as amended, of a
Registration Statement on Form S-4 (File No. 333-52397) and amendments thereto
(as so amended, the "Registration Statement"), relating to the Company's
proposed offer (the "Exchange Offer") to exchange its 7.99% Series B Secured
Bonds Due 2011 (the "New Securities") which are being registered pursuant to the
Registration Statement and which are to be fully and unconditionally guaranteed
(the "Guaranty") as to the payment of principal and interest by the Guarantor,
for an equal principal amount of the Company's outstanding 7.99% Series A
Secured Bonds Due 2011 (the "Old Securities"), pursuant to a Prospectus (the
"Prospectus") contained in the Registration Statement.

         We have examined instruments, documents, and records which we deemed
relevant and necessary for the basis of our opinion hereinafter expressed. In
such examination, we have assumed the following: (a) the authenticity of
original documents and the genuineness of all signatures; (b) the conformity to
the originals of all documents submitted to us as copies; and (c) the truth,
accuracy, and completeness of the information, representations, and warranties
contained in the records, documents, instruments, and certificates we have
reviewed.

         Based on such examination, we are of the opinion as follows:

         1.  The Company is a corporation validly existing and in good standing
             under the laws of the State of Delaware.



         2.  The Guarantor is a limited partnership duly formed, validly
             existing and in good standing under the laws of the State of
             Delaware.

         3.  The Guarantor has the limited partnership power and authority to
             execute and deliver the Guaranty and has duly executed and
             delivered the Guaranty.

         4.  The New Securities, when duly authenticated in accordance with the
             provisions of the Indenture, and when issued and delivered in
             exchange for Old Securities pursuant to the Exchange Offer as
             described in the Registration Statement, will constitute legal,
             valid and binding obligations of the Company entitled to the
             benefits of the Indenture.

         5.  When the New Securities are duly authenticated in accordance with
             the provisions of the Indenture and issued and delivered in
             exchange for Old Securities pursuant to the Exchange Offer as
             described in the Registration Statement, the Guaranty with respect
             thereto will constitute a legal, valid and binding obligation of
             the Guarantor enforceable in accordance with its terms.

         
         Our opinion that any document is valid, binding or enforceable in
accordance with its terms is qualified as to:

         (a) limitations imposed by bankruptcy, insolvency, reorganization,
             arrangement, fraudulent conveyance, moratorium, or other laws
             relating to or affecting the rights of creditors generally;

         (b) general principles of equity, including without limitation,
             concepts of materiality, reasonableness, good faith and fair
             dealing, and the possible unavailability of specific performance or
             injunctive relief, regardless of whether such enforceability is
             considered in a proceeding in equity or at law; and

         (c) rights to indemnification and contribution which may be limited by
             applicable law or equitable principles.





                  We hereby consent to the filing of this opinion as an exhibit
to the Registration Statement on Form S-4 and to the use of our name wherever it
appears in said Registration Statement. In giving such consent, we do not
consider that we are "experts" within the meaning of such term as used in the
Securities Act of 1933, as amended, or the rules and regulations of the
Securities and Exchange Commission issued thereunder with respect to any part of
the Registration Statement, including this opinion, as an exhibit or otherwise.



                                          Very truly yours,

                                          /s/ ORRICK, HERRINGTON & SUTCLIFFE LLP

                                          ORRICK, HERRINGTON & SUTCLIFFE LLP