APS Completes First Solar Trough Power Plant in Arizona and the First Built in the U.S. in 17 Years.

PHOENIX -- Arizona Public Service Company (APS) is inviting the public to help commemorate a power plant that looks nothing like - and is unlike - any other electricity-generating plant in Arizona.

Arizona's first solar trough power plant features more than 100,000 square feet of parabolic-trough shaped mirrors and stands more than 15 feet tall. Neatly aligned in 6 rows - each more than 1,200 feet long that sit on a stretch of desert between Phoenix and Tucson - the mirrors already are quietly concentrating the sun's energy and producing one megawatt of clean electrical power. This output is enough electricity to meet the demands of about 200 homes.

The plant uses a solar thermal generator and mirrors to concentrate the sun's energy to heat oil. The heat from the oil is then used to drive a turbine/generator that produces electricity.

Commercial operation of the solar trough now makes APS the largest producer of solar energy in Arizona, with more than six megawatts of solar electric generating capacity.

The solar trough is also unique from other Arizona solar generating facilities because it can actually store energy, a trait that traditional solar plants are not capable of performing. This storage capability allows the solar generators to supply electricity when needed - not just when the sun is shining. The plant also is the first to combine solar trough technology with an Organic Rankine Cycle Power Block, typically used in geothermal and biomass applications. The block allows the plant to produce more power at lower temperatures.

Public Invited to Open House

The public is invited to view this remarkable technology at an open house scheduled for 10 a.m. to 2 p.m., Saturday, April 22 at the APS Saguaro Solar Facility. The plant is located about 30 miles north of Tucson, located on the east side of Interstate 10 at the Red Rock exit. A short program will include Stan Bull, Associate Director, Science & Technology, of the National Renewable Energy Laboratory; Ken Clark, Director, Arizona Department of Commerce, Energy Office; Art Linkletter, former television personality and solar energy investor; and Ed Fox, APS Vice President, Environmental, Health and Safety.

APS and its partners, Solargenix Energy based in Raleigh, North Carolina, and Ormat International of Reno, Nevada, began construction of the $6 million plant in June 2004 and completed it 15 months later. Construction was made possible by the Arizona Corporation Commission's Environmental Portfolio Standard, a Commission program aimed at spurring development of renewable technology projects. Solargenix was the system integrator and provider of the parabolic trough and Ormat designed and installed the power conversion unit. The National Renewable Energy Laboratory provided technical expertise.

"Building the solar trough plant already has advanced the knowledge of many in the renewable energy industry," said Scott Canada, APS project manager. "APS will continue its commitment to alternative energy resources and look for additional opportunities that help bring the benefits of renewable energy to the general public."

Solargenix President John Myles said, "Solar thermal plants like this one incorporate automatic operation technology and can play an important role in meeting the increasing demand for electricity in Arizona and the southwest. We're pleased to have been selected to be a part of this project."

Dr. Udo Ungeheuer, chairman of SCHOTT Management Board, who produced the receivers at the plant, said, "Solar thermal parabolic trough power plants have the potential to be an important source of energy as the world seeks to reduce its dependence on fossil fuels."

Solargenix is a subsidiary of Acciona Energia based in Spain. It is currently constructing a 64-megawatt of solar thermal power plant in Boulder City, Nevada, which will be the largest type installed in the world when finished in about one year.

APS, Arizona's largest and longest-serving electricity utility, serves more than 1 million customers in 11 of the state's 15 counties. With headquarters in Phoenix, APS is the largest subsidiary of Pinnacle West Capital Corporation (NYSE: PNW).