EXHIBIT 5.1

                       [Choate, Hall & Stewart Letterhead]




                                 August 13, 2004


Nevada Power Company
6226 West Sahara Avenue
Las Vegas, Nevada  89146

Ladies and Gentlemen:

      This opinion is delivered in connection with the filing of a registration
statement on Form S-4, File No. 333-_____ (the "Registration Statement") under
the Securities Act of 1933, as amended (the "Securities Act"), relating to the
registration of $130,000,000 aggregate principal amount of the Company's 6-1/2%
General and Refunding Mortgage Notes, Series I, due 2012 (the "New Notes"), in
connection with an offer by the Company to issue the New Notes in exchange for
the Company's 6-1/2% General and Refunding Mortgage Notes, Series I, due 2012,
that are currently outstanding in the same aggregate principal amount (the "Old
Notes"), as described in the Registration Statement. The New Notes are to be
issued pursuant to a General and Refunding Mortgage Indenture dated as of May 1,
2001, as amended and supplemented to the date hereof (the "Indenture"), between
the Company and The Bank of New York, as Trustee (the "Trustee").

      In connection with rendering this opinion, we have examined such corporate
records, certificates and other documents as we have considered necessary for
the purposes of this opinion. In such examination, we have assumed the
genuineness of all signatures, the authenticity of all documents submitted to us
as originals, the conformity to the original documents of all documents
submitted to us as copies and the authenticity of the originals of such latter
documents. As to any facts material to our opinion, we have, when relevant facts
were not independently established, relied upon the aforesaid records,
certificates and documents.

      As counsel for the Company, we advise you as follows:

      The Company is a corporation duly organized and legally existing under the
laws of the State of Nevada.

      When the following steps shall have been taken, the New Notes will be
valid, legal and binding obligations of the Company:

Nevada Power Company
August 13, 2004
Page 2


      (a)   Compliance with the Securities Act and the Trust Indenture Act of
            1939, as amended, and action of the Securities and Exchange
            Commission permitting the Registration Statement to become
            effective;

      (b)   Execution and filing with the Trustee of the proper papers with
            respect to the New Notes; and

      (c)   Issuance and delivery of the New Notes in exchange for the Old Notes
            in accordance with the corporate authorizations and in accordance
            with the terms and provisions of the Indenture.

      We are of the opinion that the information contained in the Registration
Statement under the caption "Certain United States Federal Income Tax
Consequences" constitutes an accurate description, in general terms, of the
indicated federal income tax consequences to holders of the New Notes upon their
exchange of the Old Notes for the New Notes as contemplated in the Registration
Statement.

      Insofar as this opinion relates to matters of law and legal conclusions
governed by the laws of the State of Nevada, we base it on the opinion of
Messrs. Woodburn and Wedge of Reno, Nevada, as evidenced by the opinion of such
firm to be filed with the Registration Statement and the consent contained in
such opinion to the statements made in the Registration Statement in regard to
such firm. Our opinions as to such matters are based on the assumptions and
subject to the qualifications and limitations set forth in such opinion letter.

      We hereby consent to be named in the Registration Statement and in any
amendments thereto as counsel for the Company, to the statements with reference
to our firm made in the Registration Statement, and to the filing and use of
this opinion as an exhibit to the Registration Statement.

                                          Very truly yours,



                                          /s/ CHOATE, HALL & STEWART