One of the firms, Abenoga Solar, says that it is planning to build the largest solar power plant in the world in Arizona.

Mr Obama said the projects would provide more than 5,000 new jobs.

The Arizona plant should power 70,000 homes and cut carbon dioxide emissions.

The money will come from government stimulus funds designed to boost the economy during the recession.

Outlining the "Solana" project at Gila Bend near Phoenix, Abenoga said it would have an area of 1,900 acres, using thermal storage-equipped parabolic trough technology, with 280 MW of power output capacity.

According to the company's website, 1,500 new jobs will be created during the plant's construction with 100 positions for staff to maintain it.