Renewable Energy

In 2006, the Arizona Corporation Commission approved the Renewable Energy Standard, requiring regulated utilities, including APS, to generate 15 percent of their energy from renewable sources - solar, wind, biomass, biogas and geothermal - by 2025.

As of Jan. 1, 2007 APS has the capacity to provide 106.5 mw of renewable energy, enough for almost 30,000 homes - marking a 1,777 percent increase from the previous year. And we will continue to add renewable energy to our mix of sources of electricity through four initiatives:

• Procurement and Generation: producing and purchasing renewable energy for our customers.
• Consumer Programs: facilitating customers' use of and support for renewable energy generation, including photovoltaic grid-tied and remote solar (off-grid) systems and small solar hot water systems.
• Technology Development: developing new, more-efficient ways of producing renewable energy.
• Education and Outreach: educating teachers and consumers about the availability of renewable energy today and tomorrow.
• The APS renewable energy mix includes solar, wind, geothermal and biomass.

While APS generates a portion of our renewable energy, most is purchased through long-term contracts. In March, 2007, APS issued a Request for Proposal (RFP) for near- and long-term new sources of renewable energy that can be delivered to the company's electrical system. The RFP includes solar, wind, hybrid wind and solar, biomass/biogas, landfill gas, hydropower, fuel cells that use renewable fuels and geothermal.

Wind

In 2006, APS added a major component to its renewable energy portfolio with 90 mw of wind generation. APS signed a long-term purchase agreement with Aragonne Wind, LLC, of Santa Rosa New Mexico to purchase all the power from the 90 mw Aragonne Mesa Wind Farm. The wind farm consists of 90 wind turbines - each with a one-mw capacity - that tower 227 feet into the air and harness the wind using three, 63-foot blades. Electricity produced from the wind project is delivered to APS customers throughout Arizona and will serve approximately 22,500 homes. APS has a 20-year agreement to purchase all the power from the farm, and, when signed, it was the largest purchase power agreement for renewable energy ever signed by the company. The purchase expanded APS' renewable portfolio from 16 mw (10 mw geothermal, 6 mw solar) to 106 mw - a 563 percent increase.

Geothermal 

APS also purchases renewable energy from the Salton Sea Geothermal Power Plant west of Yuma in California's Imperial Valley. The Salton Sea Plant captures superheated, highly pressurized water from reservoirs located thousands of feet beneath the Earth's surface. When the hot water is quickly de-pressurized at the same hot temperature, it "flashes" into steam. It is this steam that is used to drive a turbine. After being cooled, the steam is transformed back into water, and reinserted into the earth. The power plant is owned and operated by CalEnergy Generation LLC, a limited liability company partly owned by MidAmerican Energy Holdings Company. APS, through a purchase power agreement, receives 10 mw - enough to serve about 2,500 homes.

Biomass

The Snowflake White Mountain Biomass Power Plant is another purchased renewable energy source for APS. The plant will come online in 2008 and generate clean energy using forest waste from wildfires, bark beetle infestation and forest management operations. APS has a long-term purchase agreement for the 24 mw of electricity the plant will produce.

Solar

APS has been a leader in solar technology research and development for more than 25 years and produces a considerable amount of its renewable energy through its solar generating facilities.

APS built the Solar Test and Research (STAR) Center in 1988 to test and develop technologies that convert solar energy into electricity. APS also uses STAR to learn how to produce lower-cost electricity from sunlight using current and emerging solar technologies such as High-Efficiency Multi-Junction photovoltaic cells (like those used on spacecraft and the Mars Rover).

This new technology uses concentrated sunlight, making it almost 50 percent more efficient than conventional photovoltaic cells. APS began working with two companies, Spectrolabs and Concentrating Technologies LLC about four years ago to test the new technology and help increase its reliability. The STAR Center began producing a small amount of electricity from this new technology in October 2004. That electricity is now being fed into the electricity grid at the test site. This application was the first known utility-produced electric power from such space cells.

As a result of its research, APS over the years has built commercial solar power plants in Flagstaff, Glendale, Gilbert, Phoenix, Prescott, Scottsdale, Tempe and Yuma. Our largest solar plant, located at the Prescott Airport generates 3.5 mw of electricity.

Our most recent solar generating facility, the Saguaro Solar Power Plant, constructed north of Tucson in 2006, is the first solar trough technology power plant to be built in the United States since 1988. Solar trough technology uses long parabolic mirrors to concentrate the sun's energy and the plant contributes one mw of electricity to the APS grid. APS' solar generation output now stands at 10 million kilowatt-hours - a record for both the company and the state of Arizona - and more new plants and expansion of existing plants are planned in the near future.

Hydrogen/Compressed Natural Gas

APS built and operates Arizona's first hydrogen/compressed natural gas fueling station in downtown Phoenix, supplying clean-burning hydrogen, CNG or a combination of the two for many of our company vehicles as well as other private hydrogen/CNG powered vehicles.