Exhibit 99.1

                            CERTIFICATION PURSUANT TO
                             18 U.S.C. SECTION 1350,
                             AS ADOPTED PURSUANT TO
                  SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

      In connection with the combined Quarterly Report of Sierra Pacific
Resources, Nevada Power Company and Sierra Pacific Power Company
(the "Companies") on Form 10-Q for the period ending March 31, 2003, as filed
with the Securities and Exchange Commission on the date hereof (the "Report"),
I, Walter M. Higgins, III, Chief Executive Officer of the Companies, certify,
pursuant to 18 U.S.C. ss. 1350, as adopted pursuant to ss. 906 of the
Sarbanes-Oxley Act of 2002, that:

      (1)   the combined Quarterly Report fully complies with the requirements
            of section 13(a) or 15(d) of the Securities Exchange Act of 1934;
            and

      (2)   the information contained in the combined Quarterly Report fairly
            presents, in all material respects, the financial condition and
            results of operations of the Companies.



/s/ Walter M. Higgins, III
----------------------------
Walter M. Higgins, III
Chief Executive Officer
May 5, 2003


THIS CERTIFICATION ACCOMPANIES THIS REPORT PURSUANT TO SECTION 906 OF THE
SARBANES-OXLEY ACT OF 2002 AND SHALL NOT, EXCEPT TO THE EXTENT REQUIRED BY THE
SARBANES-OXLEY ACT OF 2002, BE DEEMED FILED BY THE COMPANY FOR PURPOSES OF
SECTION 18 OF THE SECURITIES EXCHANGE ACT OF 1934, AS AMENDED.

A SIGNED ORIGINAL OF THIS WRITTEN STATEMENT REQUIRED BY SECTION 906 HAS BEEN
PROVIDED TO THE COMPANIES AND WILL BE RETAINED BY THE COMPANIES AND FURNISHED TO
THE SECURITIES AND EXCHANGE COMMISSION OR ITS STAFF UPON REQUEST.