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TRANSCRIPT
A Brief Introduction to Geothermal Energy and its
Utilization for Electric Power Generation
G. W. HuttrerOAS Consultant
Michela MilettoOAS Staff
Thermal means
GEO =
THERMAL =
The Earth
Crust
M Mantle
Outer Core
Inner Core
Temperatures in the Earth
2,000
4,000
6,000
4,000 C
6,000 C
Temperaturesin degrees C
Depth inKilometers
Plate Boundaries
“Ring of Fire”
Plate Tectonic Processes
Spreading Center
Oceanic Plate Subducting
Convection
Continental Plate
ConvectionCells
Rising MagmaSpreading Center
Volcanoes (as in the Caribbean)
Mt. KilueaHawaii
Magma
PermeableReservoirRocks
Geothermal Exploration Surveys
• Satellite imagery and aerial photography
• Volcanological studies
• Geologic and structural mapping
• Geochemical surveys
• Geophysical surveys
• Temperature gradient hole drilling
Geochemistry
GeophysicsGeology
Thermal Gradient Measuring
Thermal Gradient Drill
Sample Temperature Gradient Data
500
1000
1500
2000
3000
Depth/Ft
Bottom holetemperature265˚C (509˚F)
50 100 150 200 250
500
1000
1500
2000
2500
3000
Depth (Feet)
Temp. (C)
Deep Well Drill
Well Test in Progress
ProductionWell
InjectionWell
Flash Tanks
Turbine-GeneratorPower Plant &Cooling Towers
Dry Steam Power PlantTurbine Generator
SteamCondensedSteam(Water)
Electricity
Flash Steam Power Plant
Separated Water
Steam
CondensedSteam(Water)
HotWater
Turbine Generator
FlashTank Electricity
Binary Cycle Power PlantBinary Vapor Generator
Electricity
Binary Liquid
Heat Exchanger
CooledWater
HotWater
ProductionWell
InjectionWell
Heat Exchanger
Turbine Generator
CO2 Emissions Comparison(lbs/MW-hr)
Source EIA 1998; Bloomfield and Moore 1999
Geothermal
NaturalGas
Oil
Coal2000
0
1500
1000
500
Benefits of Geothermal Power• Provides clean and safe energy using little land
• Is renewable and sustainable
• Generates continuous, reliable “baseload” power
• Conserves fossil fuels and contributes to diversity in energy sources
• Avoids importing and benefits local economies
• Offers modular, incremental development andvillage power to remote sites