Pinnacle West Capital Appoints New Treasurer

March 8, 2010

PHOENIX - Pinnacle West Capital Corporation (NYSE: PNW) today announced the appointment of Lee R. Nickloy as Vice President and Treasurer of Pinnacle West and its principal subsidiary, Arizona Public Service Company, effective April 1, 2010.

With more than 20 years of energy industry experience, Nickloy, 43, comes to Pinnacle West from St. Louis-based Ameren Corporation, a utility holding company serving more than 2.4 million electricity and almost 1 million natural gas customers in Missouri and Illinois. Nickloy joined Ameren in 1998 and most recently served as Assistant Treasurer and Director of Corporate Finance. Prior to that time, he worked in a number of progressively responsible positions with other energy-related companies.

Nickloy will report to Pinnacle West Senior Vice President and Chief Financial Officer Jim Hatfield.

"We are pleased to bring aboard a professional of Lee's caliber.  He brings to our organization extensive knowledge and experience in the financial markets and will be a key contributor in supporting our corporate objectives," Hatfield said. "Lee's experience in developing and maintaining key relationships in the financial community will help Pinnacle West successfully navigate today's challenging business and financial conditions on behalf of our shareholders and customers."

Nickloy has a B.S. degree from Christian Brothers University in Memphis, Tenn., with an emphasis in economics and finance.

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.

Alan Bunnell
(602) 250-3376

Analyst Contact:

Rebecca Hickman
(602) 250-5668