What is Geothermal Energy?
• Defined: Energy that is generated by converting hot water or steam from deep beneath the Earth’s surface into electricity.
• Unique renewable• Natural Energy Flow
– Heat Mining– Enthalpy
The Heat Source
• Tiny quantities of radioactive isotopes liberate heat as they decay
• Core heat transfer through convection• Accessible in locations where heats
interior is brought within reach– Lithospheric Plates
• Significant heat flow• Volcanic activity
The Heat Source Cont’d
• High enthalpy systems are divided into two categories– Vapor Dominated
• Best and most productive• Free of liquids
– Liquid Dominated• Relies on water at boiling point• Often results in steam “flash”
• Two-phase zone
Geothermal Potential
• Nature of the resource– Fluid Temperature– Salinity– Fluid Pressure– Gas Content
• Economies of Scale• Maximum efficiency
Four Main Types
• Dry steam power plant• Single flash steam power plant• Binary cycle power plant• Double flash power plant
Global Capacity
• Worldwide use of geothermal 9.3GW– 28 GW used directly for heating– 100GWt through ground-source heat
pumps
• Potential for 65-138GW• MIT claims 100GWe by 2050• 0.3% of US energy consumption
Environmental Impact
• Gaseous emissions– Less than 1/10th of coal-fired carbon
emissions– Dissolved gasses
• Land use
• Noise
• Potential ground subsidence
Geothermal Usage
• Iceland generates 26.5% of energy from geothermal– .1% Fossil fuels– 73% Hydro
• In the US– Alaska (1 Plant)– California (4.8% of electrical energy, 2.4GW installed
capacity)– Hawaii (30MW on largest island, 20% of electrical energy)– Nevada(15 plants, 254MW)– Utah (reconstructed developing plants)
Applications in Belize
• Belize is the only country in Central America that does not have the potential for geothermal energy according to the US Department of Energy
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