Eight kinds of beer and freshly shucked oysters make the Innamincka Hotel an oasis for travelers on Australia's remote Strzelecki Track. But keeping food and drink cold in the Outback isn't cheap. Every three weeks a diesel tanker must make a 1,600-km round trip from Port Augusta, South Australia, to keep the generators running. Not, perhaps, for much longer. By Christmas, the dozen or so residents of Innamincka, about 1,100 km north of Adelaide, have been promised a miracle: free electricity for decades to come. If all goes to plan, the beer will soon be cooled by zero-emissions renewable energy trapped deep beneath the surrounding desert. "It's an absolutely brilliant thing," says Leon Cartledge, manager of the hotel, which in busy times gulps about $20,000 worth of diesel a month. "For one thing, you'll be able to come out to the bush and not hear generators humming. And it will be clean power." Affordable, carbon-free energy available around the clock is the Holy Grail in a world that aspires to cut greenhouse-gas output even as it uses ever more electricity. Solar power can't provide it; nor can wind. And while nuclear power could do so, many Australians oppose it. One answer may come from tapping the heat stored in rock strata at least 5 km below the surface in many parts of the world, including Europe, India, China, the U.S. and Australasia. A report by the Massachusetts Institute of Technology last year argued that by mid-century, this type of geothermal energy could supply 10% of America's power. Innamincka has some of the hottest rocks anywhere, and Geodynamics has spent $150 million drilling deep into them. The biggest and most advanced of some 40 companies seeking to capture Australia's underground heat, it aims to be the first to prove that deep-earth geothermal power is commercially viable. Geothermal is already a bit player in the power business: underground water heated by volcanoes is already used for heating and electricity generation in countries like Iceland and New Zealand. But supplies of natural hot water are limited. The new push is to mimic nature by creating artificial water-heating systems using hot subterranean granites. The resource is potentially endless: while each patch of rock will cool as its energy is drawn off, it will heat up again if left alone. In theory, says Geodynamics chief executive Gerry Grove-White, there's enough heat in the rocks of the Cooper Basin, on which Innamincka sits, to replace all the coal-fired power stations in Australia for more than 250 years. He says one cubic kilometer of hot granite has about the same stored energy as 40 million barrels of oil. With several thousand cubic kilometers of these granites, Australia has enough heat to last millennia. "We're being watched worldwide," says Grove-White, a British power-industry veteran whose experience covers four continents and every system, from wind and hydro to nuclear and coal. "The climate debate has focused an awful lot of interest on the commercial development of these resources." The Innamincka granites are buried under 3 km of sedimentary rock, which acts like a blanket on a bed. Heat is generated by the radioactive decay of elements in the granite, but it can't escape. Five km below the surface, the rocks' temperature is 250