Apple is building itself a giant solar power station to run its futuristic new headquarters.

The global tech giant has released new information on the plan to build an intriguing new building on a 2,900-acre site in rural San Francisco.

The plan for the giant elliptical building has been referred to as a “Halo”, “doughnut” or “UFO”.

Now the company says it will spend nearly $A1.09 billion on a solar energy project to generate power for the new corporate headquarters, retail stores and other operations in California.

Apple chief executive Tim Cook told an investment conference in San Francisco last week that the project reflected the company’s concern about climate change.

It will also save money on future power bills and generate income by allowing other users to share in the supply.

US company First Solar will build the 280-megawatt facility.

Apple has signed a 25-year contract to use 130 megawatts of the plant's capacity, which should be enough to power Apple’s new headquarters, along with all of its other offices in the state, and 52 California retail stores and a computer centre.

First Solar will then sell the remaining electricity to the state’s chief energy utility.

Construction will begin later this year, and the site should start generating power by late 2016.