Geothermal Energy: the Power of Hot Rocks

Geothermal power is generated from heat stored underneath the earth's crust. In the booming business of renewable energy, geothermal is set to play a major role. The United States Department of Energy's Geothermal Technologies Program supports development and exploration of geothermal technologies, which may someday provide an abundant source of energy with the "clean and green" stamp of approval. Currently, combined geothermal energy usage in 21 countries around the world generates approximately 7,000 megawatts per year. The United States is the largest producer of geothermal electricity in the world, about 2700 megawatts per year, but the potential for geothermal power is much greater.

In the geothermal power industry, energy to turn turbines and make electricity is generated with water heated by hot rock that lies beneath the earth's crust. In some areas of the world, hot water in the form of steam spews spontaneously from the ground. For example, The Geysers, in the Mayacamas Mountains of Northern California, is the home of a large complex of geothermal power plants. Areas known for volcanic activity are ideal for tapping geothermal power. Here, reservoirs of hot water can be found fairly close to the surface. However, geothermal experts say that underground heat can be utilized almost anywhere on the planet with a process that requires deep drilling to reach hot dry rock. Water is pumped into the ground at high pressure, creating fissures as it moves through the rock. In a closed-loop system that allows continued electricity generation, water absorbs heat from the rock, and returns under pressure to the surface.

Geothermal heat is available in an unlimited supply. Widespread utilization of geothermal power could help to reduce dependence on oil, natural gas, coal, and nuclear power. Wind and solar power are already proving their value as renewable energy sources. Geothermal power plants offer the advantage of round-the-clock base load electricity generation. According to an MIT panel of experts, geothermal systems now in use in California, Hawaii, Utah, and Nevada have output comparable to solar and wind power combined. Unlike fossil fuel and nuclear power, geothermal power has a minimal impact on the environment.

Interest in geothermal research and development is at an all-time high, but large-scale commercial use is most likely years down the road. As the renewable energy business heats up, geothermal power will inevitably become a key player. Humanity's quest to reduce fossil fuel consumption is under way, and the day will come when geothermal power provides a substantial contribution to the electrical grids of both major cities and small towns. In the quest for clean, affordable, and sustainable fuel sources, geothermal power holds great promise. As humanity struggles to free itself from the environmental, economic, and political liabilities associated with fossil fuel consumption, we can take comfort knowing that lying just a few kilometers below our feet is an endless supply of energy we can all feel good about.

References

http://www.geysers.com/

http://pesn.com/2007/01/22/9500449_MIT_Geothermal_Report/

http://www1.eere.energy.gov/geothermal/