The city of Phoenix's Lake Pleasant Water Treatment Plant is working directly with the sun to produce energy for the plant, which produces 15 billion gallons of tap water each year. A 7.5-megawatt high efficiency solar power system, designed and built by San Jose, Calif.-based SunPower Corp. is expected to generate 70 percent of the plant's electrical power needs. Nearly 23,000 solar panels are being used to save approximately 15 million kilowatt-hours (kWh) each year, resulting in savings of approximately $4.2 million over the next 20 years as compared to conventional electricity.
According to estimates provided by the U.S. Environmental Protection Agency, the system is expected to offset the production of more than 9,000 tons of carbon dioxide per year, which is equivalent to removing almost 35,800 cars from Arizona's roads over the next 20 years.
"With more than 300 days of sunshine each year, Phoenix is a natural for using solar power," says Phoenix Mayor Greg Stanton. "The Lake Pleasant Water Treatment Plant project is the latest in a series of solar initiatives utilized at various city locations to increase the city's commitment to sustainable energy development."
At the Lake Pleasant Water Treatment Plant, a 6-megawatt ground-mounted solar array features a SunPower T0 Tracker system, which positions solar panels to follow the sun's movement during the day, increasing sunlight capture by up to 25 percent over conventional fixed-tilt systems, while significantly reducing land use requirements. The SunPower T10 Solar Roof Tile was used for a 1.5-megawatt array atop a reservoir.
Phoenix is financing the system through a solar services agreement with SunPower. Under terms of the agreement, Wells Fargo owns the system that SunPower designed, built, and will operate and maintain. The city will buy the electricity at rates that are competitive with retail electricity, minimizing the effect of rising electricity costs with no capital investment. The renewable energy credits (RECs) associated with the system will be transferred to Arizona Public Service (APS) in fulfillment of the state's renewable energy standard. The project was facilitated in part by APS's Renewable Energy Incentive Program, which offers financial incentives to customers that help to offset up to 40 percent of the costs of installing solar energy.