Apple will spend nearly $US850 million ($A1.09 billion) on a solar energy project that will generate enough power for the computer giant's new corporate headquarters, retail stores and other operations in California.

The tech company will be the biggest single consumer of energy from the new solar facility. It is being constructed on 2,900 acres in rural Monterey County, south of the San Francisco Bay Area where Apple is headquartered. The project reflects Apple’s concern about climate change, chief executive Tim Cook…