Geothermal energy is accessed by drilling wells a mile or deeper below the surface of the Earth. There are several technologies for converting geothermal energy to electricity, but the two most common technologies in the U.S. are flash steam and binary technologies. Flash steam geothermal plants harness the high temperature and pressure of a geothermal reservoir to generate steam that drives a steam turbine and returns water to the reservoir. Binary plants use heat exchangers with a heat exchange fluid to drive a steam cycle.
Role of Alternative Energy Sources: Geothermal Technology Assessment
Geothermal power is a proven technology with a large resource base, and the use of flash steam technology has relatively low capital costs that translate to a competitive cost of electricity. However, the characteristics of geologic formations are highly variable and are a barrier to broad implementation of geothermal power. Further, the naturally-occurring CO2 in geofluid leads to relatively high greenhouse gas emissions from geothermal power plants that use flash steam technology.
Authors: Tim Skone, James Littlefield, Robert Eckard, Greg Cooney, Joe Marriott, PhD
Date: August, 2012
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