General Motors is installing solar panels on a facility in Fontana, in sunny southern California. When completed in December, the installation will produce 1.3m kilowatt hours of electricity a year, roughly the amount needed to power 500 homes for one year.

The installation of Uni-Solar PV solar panels by United Solar Ovonic, a subsidiary of Energy Conversion Devices, is said to be one of the largest solar power installations in corporate use.

The solar array is going up on top of GM's 300,000 square foot warehouse facility in Fontana and follows a similar-sized installation by the company at another GM facility in Rancho Cucamonga about 13 miles away.

This area, in the 'Inland Empire' 50 miles east of Los Angeles, is known for its hot weather and almost year-round sun and is ideal for solar panel installations.

GM's vice president of environment, energy and safety policy, Elizabeth Lowery, said: "The new solar arrays on our rooftops are reducing our energy costs and carbon footprint, while providing green energy to the community."

Constellation Energy Projects & Services Group, a division of Constellation Energy, will own and operate the rooftop system and provide power to the GM facility under a 25-year power purchase agreement.