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Geothermal Energy. By Chris Gibson Richard Nauert. Geothermal Energy. Geothermal energy is heat contained in underground rocks and fluids It is a renewable resource but can be depleted if heat is removed faster than what can be replaced
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Geothermal Energy By Chris Gibson Richard Nauert
Geothermal Energy • Geothermal energy is heat contained in underground rocks and fluids • It is a renewable resource but can be depleted if heat is removed faster than what can be replaced • Over millions of years, this heat has been transferred to reservoirs of dry steam, wet steam, and hot water • These deposits are trapped in porous rocks near the crust
Geothermal Wells • If the geothermal site is close to the surface, wells can be drilled • The steam is extracted, spins a turbine, and then injected back into the rock • The thermal heat is then used to heat homes and produce electricity
How does a geothermal power plant work? Steam spins a large turbine which then generates electricity Heat from the steam is exchanged with the fluid in the power plant system Steam is removed from porous rocks underground through wells MODEL The original water is re-injected back into the ground
Advantages • Very high efficiency • Moderate net energy at accessible sites • Lower CO2 emissions than fossil fuels • Low cost at favorable sites • Low land use • Low land disturbance • Moderate environmental impact
Disadvantages • Scarcity of suitable sites • Depleted if used too rapidly • CO2 emissions • Moderate to high local air pollution • Noise and Odor (H2S)
Usage • The United States accounts for about 38% (7,000 megawatts) • The Philippines is the second largest user • Iceland uses geothermal energy to heat every building
Bibliography Miller, G. Tyler. Living in the Envrironment. Brooks/Cole, 2004. Images: http://1.bp.blogspot.com/_5rb8OzBF17U/R1MhCKO313I/AAAAAAAAAWY/zV93WvxXNxw/s1600-R/GeothermalPowerStation.jpg http://www.greeninmedusa.com/photos/uncategorized/2007/10/23/geothermal.jpg http://apps1.eere.energy.gov/consumer/images/geothermal_map.gif http://www.liv.ac.uk/science_eng_images/earth/geothermal.jpg http://www1.eere.energy.gov/geothermal/images/binaryplant.gif