Transcript Geothermal Energy

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
The original water is
re-injected back into
the ground
MODEL
Advantages
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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
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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/geother
mal.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