SunPower has installed 5.4MW of SunPower E20 solar panels on three rooftop locations at Phoenix Sky Harbour International Airport. The system is expected to generate the equivalent of 51% of the electricity demand at the airport's rental car centre, two East Economy parking garages and toll plaza, saving US$4.7 million over the next 20 years. The installation was constructed in two months.

According to estimates provided by the U.S. Environmental Protection Agency, the system is expected to offset the production of more than 5500 tons of carbon dioxide per year, which is equivalent to removing 19,800 cars from Arizona's roads over the next 20 years.

"With this SunPower system, Sky Harbor Airport is reinforcing its commitment to energy conservation and improving air quality in Arizona, while saving airport funds," said Phoenix mayor Greg Stanton. "Councilman Bill Gates has been championing this effort at the city and it's exciting to see it come to fruition."

The project was facilitated in part by Arizona Public Service Company's (APS) renewable energy incentive program, which offers financial incentives to customers that help to offset up to 40% of the costs of installing solar energy.

The airport is hosting the system and buying electricity at rates that are competitive with retail electricity, providing a hedge against rising electricity costs with no capital investment. The renewable energy credits associated with the energy produced by the system will be transferred to APS in fulfilment of the state's renewable energy standard and tariff.