The Interior Department on Thursday approved plans to open 190 million acres of federal lands for geothermal exploration and development.

In Utah, it's estimated that geothermal drilling could impact 9.5 million acres of BLM land and more than 2.7 million acres of Forest Service property. Lands within national parks will be closed to geothermal leasing under the new plan.

"Geothermal energy will play a key role in powering America's energy future," Interior Secretary Dirk Kempthorne said Thursday in a prepared statement.

The department estimates that by 2015, development of public lands leased for their geothermal resources will produce 5,500 megawatts of new electric generation capacity from supplies in 12 Western states. By 2025, currently untapped resources in those states, including Utah, are expected to produce 12,100 megawatts of electricity.

Kempthorne said as many as 270 Western communities could benefit from the energy produced by new geothermal resources. The development of those resources would require amending 114 Bureau of Land Management resource-management plans for about 111 million acres of public land. The rest of the geothermal energy would come from 79 million acres of National Forest Service lands.

The Interior Department in late October unveiled the plans to open the public lands for geothermal development. The department named 18 areas in Utah that could be affected, including Park City, St. George and Box Elder County. The lands also included an area that borders Zion National Park, remote locations such as the Book Cliffs that span Carbon and Grand counties, and the Henry Mountains in Garfield County.

So far, watchdog groups such as the Sierra Club have supported the Interior Department's geothermal energy goals, which are shared by Utah Gov. Jon Huntsman Jr. He wants 20 percent of the state's electricity needs to be met by 2025 through renewable sources such as solar, wind and geothermal energy.

The first part of a Bureau of Land Management lease sale scheduled for Friday in Salt Lake City is to auction off parcels slated for geothermal development. The sale, which also includes parcels for oil and natural-gas development, has been hotly contested by environmental groups for offering parcels that the critics say are too close to Arches and Canyonlands national parks, Dinosaur National Monument and other culturally and environmentally sensitive areas in Utah.