The term Geothermal originates from two Greek words 'GEO' and 'THERM'. The Greek word ‘geo’ means the earth whilst their word for ‘therm’ means heat from the earth. Geothermal energy is energy derived from the heat of the earth. The earth’s centre is a distance of approximately 4000 miles and is so hot that it is molten. Temperatures are understood to be at least 5000°C. Heat from the centre of the earth conducts outwards and heats up the outer layers of rock called the mantle. When this type of rock melts and becomes molten it is called magma. Magma can reach just below the earths surface. Rain water sometimes seeps down through geological fault lines and cracks becoming super heated by the hot rocks below. Some of this superheated water rises back to the surface of the earth where it emerges as hot springs or even geysers. Sometimes the hot water becomes trapped below the surface as a geothermal reservoir. One way of producing electricity from geothermal energy is by drilling wells into the geothermal reservoirs. The hot water that rises emerges at the surface as steam. The steam is used to drive turbines producing electricity. If the water is not hot enough to produce steam, it can still be used to heat homes and businesses, saving gas/electricity. Geothermal energy is the heat from the Earth. It is clean and sustainable. Resources of geothermal energy range from the shallow ground to hot water and hot rock found a few miles beneath the Earth's surface, and down even deeper to the extremely high temperatures of molten rock called magma.
Key words: Geothermal, energy, geothermal electricity, geothermal water, energy harnessed.
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