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?!!