E7-16384. Pinnacle West Capital Corporation, Arizona Public Service Company, Pinnacle West Energy Corporation, APS Energy Services Company, Inc; Notice of Institution of Proceeding and Refund Effective Date

August 14, 2007.

On August 13, 2007, the Commission issued an order that instituted a proceeding in the above-referenced docket, pursuant to section 206 of the Federal Power Act (FPA) 16 U.S.C. 824e, to determine whether Pinnacle West Capital Corporation's, Arizona Public Service Company's, Pinnacle West Energy Corporation's and APS Energy Services Company, Inc.'s (collectively, Pinnacle) market-based rate authority for the non-APS portion of the Phoenix Valley remains just and reasonable during the summer months. Pinnacle West Capital Corporation, 120 FERC ¶ 61,153 (2007).

The refund effective date in the above-docketed proceeding, established pursuant to section 2069(b) of the FPA, will be the date of publication in the Federal Register.

Kimberly D. Bose,

Secretary.