03-01-2013, 03:23 PM
What is Geothermal Energy?
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What is Geothermal Energy and where does it come from?
Geothermal energy is contained in reservoirs of steam, hot water, and hot dry rocks underground
The earth's crust is broken into plates where magma comes close to the earth's surface near the edges
Underground, rocks and water absorb heat from magma
Geothermal energy occasionally rises to the earth's surface in the form of volcanoes, hot springs, and geysers
Plate boundaries in the earth's crust contain some of the most active geothermal resources; the Ring of Fire, located around the rim of the Pacific Ocean, is a hotbed of geothermal activity
Ground water trapped in porous rocks or water running along fractured rock surfaces and faults is heated by magma when it comes close to the surface.
Geothermal reservoirs are large areas of hydrothermal resources
Outside of areas with obvious geothermal activity, it is still possible to trap the heat from the earth.
Pros and Cons of Geothermal Energy
There has been an ongoing debate pertaining to the pros and cons of geothermal energy. Before we can begin to discuss the advantages and disadvantages, we need to have a clear understanding of what exactly geothermal energy is. 4,000 miles below the Earth's surface is incredibly hot. It is thought to be over 7,000 degrees Fahrenheit. While this temperature is extremely dangerous and must be avoided, if you were to drill about 3 or 4 miles below the Earth's surface, you can find a hot rock that is far less dangerous, and it is at only 300 to 400 Fahrenheit. This rock and heat can be used as a constant source of heat but would prove to be very expensive. Now while drilling and using this hot rock can be extremely expensive, there are other alternatives. In some places, only a few hundred feet below the surface there are areas that have combined this hot rock and underground water to produce hot water streams. This is the most economic source of heat below the earth and can be used in a number of ways. The heat can be used to heat homes, businesses and even run large farms or provide energy for greenhouses.
Geothermal Power Plants
One very promising use of geothermal power is the generation of electricity with geothermal power plants. Areas with hot geothermal reservoirs can use this heat and steam to create electricity without having to spend money for fuel and without polluting the atmosphere or ground. Geothermal power plants have much in common with traditional power generating stations. They use many of the same components, including turbines, generators, heat exchangers, and other standard powergenerating equipment. All geothermal power plants use geothermal steam to turn a turbine. The turbine is attached to a generator that creates the electricity which is fed into a grid leading to individual users. See our animation below.