PHOENIX - Pinnacle West Capital Corp. (NYSE: PNW) announced today that it plans to release its second-quarter results before the U.S. financial markets open on Tuesday, August 3, 2010.

That same day at 12:00 noon (ET), the Company also will host a live webcast of management’s conference call to discuss the Company’s 2010 second-quarter results, as well as recent developments. The webcast can be accessed at www.pinnaclewest.com/presentations and will be available for replay on the website for 30 days. To access the live conference call by telephone, dial (877) 356-3961 and enter Conference ID 82449914. A replay of the call will be available until 11:55 p.m. (ET), Tuesday, August 10, 2010, by calling (800) 642-1687 in the U.S. and Canada or (706) 645-9291 internationally and entering the same Conference ID number as above.

Pinnacle West is a Phoenix-based company with consolidated assets of about $12 billion. Through its subsidiaries, the Company generates, sells and delivers electricity and sells energy-related products and services to retail and wholesale customers in the western United States.

Media:
Alan Bunnell, (602) 250-3376

Analyst:
Rebecca Hickman, (602) 250-5668