The U.S. approved three renewable-energy projects to be built on federal land in California and Nevada.

The two solar farms and one wind project are expected to total 1,100 megawatts of capacity, enough to power more than 340,000 homes, Interior Secretary Ken Salazar said today at a press conference in San Francisco.

The U.S. doubled its use of renewable-energy during the past four years and these projects are part of the Obama administration’s strategy of promoting wider use of solar, wind and geothermal energy on federal lands, he said. The solar farms are in one of 17 zones approved by the Interior Department last year to accelerate the approval process.

“They are the blueprint, the bible, if you will, of where solar energy will go on public lands in the years ahead,”Salazar said.

The 750-megawatt McCoy Solar Energy Project, owned byNextEra Energy Inc. (NEE), and Electricite de France SA’s 150-megawatt Desert Harvest plant will use photovoltaic technology and are in Riverside County, in Southern California.

Duke Energy Corp. (DUK)’s 200-megawatt Searchlight Wind Energy Project is in Clark County, Nevada.

Edison International (EIX)’s Southern California Edison utility received approval from state regulators last year to buy power under a 20-year contract from McCoy’s first 250-megawatt phase, which is expected to start producing power in late 2016.

EDF and Duke haven’t announced power-purchase agreements and none of the three companies have named suppliers.