Transcript Breaking New Ground with Geothermal Energy

Breaking New Ground with
Geothermal Energy
Elissa Ledvort, Matthew Wala
Getting to Know Geothermal
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What is
geothermal
energy?
Geo – Earth
Therme – Heat
Part of the
Earth’s heat that
could be
recovered and
exploited by man
3 Uses of Geothermal Energy
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Direct Use and District Heating Systems
Electrical Generation
Geothermal Heat Pumps
I Still Don’t Get It
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Under Earth's crust, there is a layer of hot, molten rock called magma. Heat is
continually produced from the decay of naturally radioactive materials.
SO HOTT!! “The amount of heat within 10,000 meters of Earth’s surface
contains 50,000 times more energy than all the oil and natural gas resources in
the world.”
The areas with the highest underground temperatures are in regions with
active or geologically young volcanoes, specifically at plate boundaries or at
places where the crust is thin enough to let the heat through.
Includes the Pacific Rim (Ring of Fire), Alaska, California, Oregon, and Nevada
Seismically active. “Earthquakes and magma movement break up the rock
covering, allowing water to circulate. As the water rises to the surface, natural
hot springs and geysers occur, such as Old Faithful at Yellowstone National
Park. The water in these systems can be more than 200°C (430°F).”
Geothermal energy is produced when cools water seeps into Earth’s crust, is
heated, and forced to the surface. This is then harvested for energy (naturally
occuring geothermal energy).
Direct Use and District
Heating Systems
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Well brings hot water to the surface
Mechanical system delivers heat to the
processes
Provides heat for buildings, crop and lumber
drying, aquaculture, and horticulture
Direct Heating Systems – hot water near
Earth’s surface is pumped directly into
buildings and industries for heat
Not hot enough for electricity
Electricity Generation
(Geothermal Power Plants)
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Commercial use
Hydrothermal Systems– “subterranean geothermal reservoir
that transfers heat energy upward by vertical circulation of
fluids driven by differences in fluid density that correspond to
differences in temperature”
Deep Geothermal System – extracts heat through created
subsurface fracture system where water is injected through
injection wells. The water is heated by the contact with the
rock and returns to the surface through production wells
(similar to hydrothermal)
Two types of hydrothermal systems: vapor-dominated and hot
water
Require high temperatures (300-700 F) that comes from dry
steam wells or hot water wells, accessed by drilling wells into
Earth and piping steam or hot water from 1-2 miles deep to the
surface.
Electricity Generation
(Geothermal Power Plants)
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3 Types of Power Plants
Dry Steam Plant – uses steam piped directly from geothermal
resovoirs to turn generator turbines
Flash Steam Plant – (most common type) high pressure water from
deep inside Earth is converted to steam, which drives generator
turbines. The steam cools water and is condensed and injected back
into the ground to be used over again
Binary Plants - uses subterranean water to vaporize a second fluid
for heating5
Transfers heat from geothermal hot water to another liquid. The heat
causes the second liquid to turn to steam, which drives a generator
turbine
Binary plants will most likely dominate in the future of geothermal
energy.5
Geothermal Power Plants
continued
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Geopressurised Resources – “deeply buried
resovoirs of hot brine, under abnormally high
pressure, that contain dissolved methane” used
along Pacific West Coast
Co-produced Geothermal Fluids – “produced water
cut” are HOT and often found in waterflood fields by
many U.S. oil and gas production areas
This is nuissance to oil and gas industry, but
“diminishes greenhouse gas emissions and extends
the economical use of an oil or gas field”
Geothermal Heat Pumps
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Temperature in upper 10 ft of Earth’s surface
is between 50-60 degrees Fahrenheit.
Geothermal Heat Pumps – transfers heat
from ground into buildings during winter, and
air conditioning during summer
EPA!!!! – most energy efficient,
environmentally clean, cost-effective systems
for temperature control
Benefits ;)
• Economical and environmental
• Consumes no fuel and creates few
emissions.
• Abundant (proven by
Massachusetts Institute of
Technology, MIT)5
• Renewable!
• Virtually no complaints4
Geothermal Future?
• Geothermal energy is a respectable method of
exploiting renewable energy
• Why don’t we use it more?
• Initial Costs3
• Exploratory drilling is a tedious effort and time
waster3
• But…….
Geothermal = Great Long-term
Investment
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Positive impact on environment,
consuming no fuel and creating few
emissions4
MONEY SAVER when analyzing
long term costs
But currently, it’s underused 
We Still Have Hope
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Geothermal energy is gaining popularity
in the world.
24 countries currently using a form of
geothermal energy.5
The United States uses the most
geothermal energy, 2,850 MW of the
world’s 8,900 MW.5
Current State of World Energy
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Oil and gas accounted for
63% of world energy usage
in 2005 (oil was the most
used)1
Non-hydroelectric renewable
resources = <1% of world
energy use1
World uses 84 million
barrels of oil a day; 30 billion
per year3
US uses double the energy
it produces3
Oil Production and Prices
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Oil resources are finite
and production has
already peaked outside
the Middle East
There is “substantial
range of uncertainty in
the world’s future oil
markets.”2
Oil Market Uncertainty
Predicted
Actual
Geothermal Energy in the
United States
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US is largest user and producer of
geothermal energy3,5
0.36% of US electricity supply is
generated with geothermal power5
The Geysers in California is the
largest geothermal plant in the
world5
Geothermal heat pumps power
homes and buildings in all 50
states3
39.2% of potential energy in the
United States is geothermal;
unfortunately, most of it cannot be
used3
US Geothermal Resources
Geothermal Technology
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Enhanced (deep
geothermal systems) will
inject water into rock; will
not require reservoir
water3
Co-pressured geothermal
fluids: hot water as a
byproduct of oil and gas
drilling is currently
discarded; it could have
produced 7585 MW of
power in 20043
Geothermal Technology
(continued)
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US geothermal
energy development
is expected to
increase by four
times from current
levels by 20153
Geothermal heat
pumps eventually
pay for themselves5
Financial Aspect of Geothermal
Energy
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Most expensive part of
geothermal power plant is
excavation and
construction; initial costs
may tempt investors into
overusing resources
beyond sustainable levels3
Geothermal plants are
cost-effective: “on par with
or better than coal plants”5
Environmental Impact of
Geothermal Energy
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Very minimal environmental
impact: “minor, restrainable, or
negligible”4
Dissolved metal and gas in
some reservoir water needs to
be cleaned out unless using
binary plants5
Most likely problems deal with:
water pollution, waste disposal,
and high noise levels4
Injection of water may lead to
more frequent small
earthquakes4
Geothermal Energy as
Sustainable, Alternative Energy
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Above: recovery of temperature in a
geothermal reservoir
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Sustainability: “Meeting the
needs of the present
generation without
compromising the needs of
future generations.”4
Renewable resource:
geothermal fields will
recover to original state in
30-100 years4 after
exploitation
Alternative energy:
Geothermal resources will
equal resource of ~3.5
billion barrels of oil by 20503
Sources: text
1.
http://www.eia.doe.gov/pub/international/iealf/table18.xls
2. http://www.eia.doe.gov/oiaf/ieo/oil.html
3. “Geothermal – The Energy Under Our Feet”. Bruce Green and Gary Nix, National Renewable Energy Laboratory, 2006
4. “Geothermal energy: sustainability and the environment”. L Rybach, 2003
5. “Heating Up”. Mark Fischetti, October 2007 Scientific American
http://www.ucsusa.org/clean_energy/renewable_energy_basics/offmen-how-geothermal-energy-works.html
http://www.eia.doe.gov/kids/energyfacts/sources/renewable/geothermal.html
Sources: pictures (in order)
http://iga.igg.cnr.it/geoworld/galleria/igaice1.gif
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2 of text source 5
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3A.gif
http://www.ccs.neu.edu/home/gene/peakoil/nonopecfsu.gif
http://www.eia.doe.gov/oiaf/ieo/images/figure_35.jpg
http://www.wtrg.com/daily/clfclose.gif
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http://pesn.com/2007/01/22/9500449_MIT_Geothermal_Report/twowell_Enhanced_Geothermal_System_400.gif
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http://www.cnbceb.com/images/2007/apr/spring.jpg
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