Geothermal Energy

Presented by:

William MurrayMarch 28, 2007

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

Dry Steam Power Plant

Single/Double Flash Steam

Binary Cycle Power Plant

Ground Source Heat Pump

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

QUESTIONS?!!