13. Can cuase minor earth quakes like those caused by Hydraulic fracturing.
Editor's Notes
This is the front slide
7 0% comes from the decay of radioactive nuclei with long half lives that are embedded within the Earth Some energy is from residual heat left over from Earths formation. The rest of the energy comes from meteorite imp acts.
Around the world geothermal energy is used in various different ways. In New Zeland the Maori people have traditionally used heat rising from the ground to cook food. Other cultures, like the Japanese, have used hot springs which are naturally heated by geothermal energy as hot water for spas. The most convientent use is in the generation of electricity. Around the world some are more suitable for geothermal energy use because they lie on the boundry of a tectonic plate. At tectonic plates the earth's crust is very thin and, in case of vocaneos, sometimes the magama, the molten rock from the mantel, can erupt onto the land. Hence some places are rich in geothermal energy, such as Iceland, the west coas of North American, New Zealand etc. The UK does not lie on a fault line so there is not much geothermal energy for us to use, but the government is investing money into its development. An early scheme in the UK is in Southampton. The well in Southamoton is 1,800 metres deep and water is extracted from it at a temperature of 76°C. The scheme now heats a number of buildings in the city centre, including the Southampton Civic Centre and the WestQuay shopping centre, by providing 8% of the heat distributed by a larger city centre district heating system that includes other combined heat and power sources. Geothermal energy provides 16 GWh of heat per year. Worldwide power generation was 67,246 GWh of electricity in 2010 Research is being done to use the North Sea which has a thinner crust.
There three types of geothermal power plants. They all follow the same sort model in that they use steam turbines to generate electricity. Dry steam plants are the simplest and oldest design. They directly use geothermal steam of 150°C or greater to turn turbines. Flash steam plants pull deep, high-pressure hot water into lower-pressure tanks and use the resulting flashed steam to drive turbines. They require fluid temperatures of at least 180°C, usually more. This is the most common type of plant in operation today. Binary cycle power plants are the most recent development, and can accept fluid temperatures as low as 57°C. The moderately hot geothermal water is passed by a secondary fluid with a much lower boiling point than water. This causes the secondary fluid to flash vaporize, which then drives the turbines. This is the most common type of geothermal electricity plant being constructed today. Both Organic Rankine and Kalina cycles are used. The thermal efficiency of this type plant is typically about 10-13%.
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