3/25/2010 Geothermal Energy Spencer Smith

Definition ✤ Geothermal energy is power extracted from the heat stored in the earth. ✤ Originates from the formation of the planet, and the radioactive decay of materials within. ✤ In ancient Roman times, it was used for space heating and bathing, but currently is being used to produce electricity. ✤ Supplies about 0.3% of global electricity, including heating, industrial processes, and agricultural applications. ✤ Cost effective, reliable, sustainable, and environmental friendly.

Electricity ✤ 24 countries are using geothermal energy, and production is growing by 3% annually. ✤ Power plants have been limited to the edges of tectonic plates until recently. ✤ Because geothermal power does not rely on variable sources of energy, such as wind or solar, therefore the capacity factor is high. ✤ The largest geothermal power plants in the world is located in ‘The Geysers’, a geothermal field in California. ✤ Development in some countries stopped after production was believed to have triggered earthquakes.

Application ✤ Direct heating is by far more efficient than electricity generation. ✤ More than half is used for space heating, and another third for heated pools ✤ Heat may come from co-generation with a direct application and a geothermal electrical plant. ✤ Where natural hot springs are available, water can be directly placed into radiators. ✤ Where the ground is hot and dry, earth tubes can be used to collect heat.

Environment ✤ Fluids drawn from the earth contain a mixture of gases, most notably carbon dioxide, hydrogen sulfide, methane, and ammonia. ✤ These pollutants can lead to global warming and acid rain. ✤ A process where these gases are returned to the earth is in development. ✤ Plant construction can affect land stability. ✤ Geothermal is generally efficient, and use minimal land and water.

Economics ✤ Requires no fuel, therefore does not contain fuel cost fluctuations, but capital cost tend to be high. ✤ Electricity generation cost about 10 million dollars to start, and has a 20% failure rate. ✤ The bigger the plant, the more power it can produce ✤ Chevron Corporation is the world’s largest private producer of geothermal electricity.