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Innovation: Enhanced Geothermal System
AltaRock Energy taps the Earth's core for energy. Here are all the parts of the process. Roll over the numbers below to take a closer look.
Tapping the earthâ€™s core for energy
Geothermal energy holds great promise as a renewable source of round-the-clock electricity. But large-scale geothermal power pro- duction, which involves harnessing energy generated by the heat of the earthâ€™s interior, has proved difficult and expensive. AltaRock Energy of Seattle has developed a process that could be a breakthrough. The companyâ€™s enhanced geothermal system, or EGS, involves pumping clean water into naturally occurring fractures two to three miles below the earthâ€™s surface, creating three reservoirs. There the water is heated to temperatures as high as 600 degrees Fahrenheit and pumped back up to a power plant to produce electricity. (Conventional systems are confined to locations with naturally occurring geothermal reservoirs.) Last June, AltaRock began work on an EGS project near the Newberry volcano in Deschutes National Forest in Oregon, installing equip- ment to monitor groundwater and seismic activity. The company, founded in 2007 by geothermal engineer Susan Petty, has raised more than $50 million in funding from venture capital firms, Google, and the U.S. Department of Energy. Petty expects the Oregon plant to begin producing 15 megawatts of electricity, enough to power 15,000 homes, by 2017.