Here’s some steamy action: The Department of Interior on Wednesday announced plans to open 97 million acres of public land in 12 states to geothermal energy development. The plan could more than quadruple the U.S.’s current output of underground-heat power, potentially generating enough electricity to power 5.5 million homes by 2015 and 12 million by 2025. Some national forestland could be leased under the plan, though national parks, including geyser-full Yellowstone, are off-limits. Kempthorne praised geothermal energy as “a renewable resource that generates electricity with minimal carbon emissions … [and] reduces the need for conventional energy sources.” Indeed, you’ll note that geothermal energy needs no qualifier, unlike “clean coal” and “safe, clean nuclear power.”