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CT: Geothermal has an even longer history in Iceland, where legend has it that people first used geothermal heat 1,000 years ago to warm their homes and bathed in the hot water. But it wasn’t until the first oil-price shock of the 1970s that Iceland used geothermal heat to generate electricity. Today, the National Energy Authority says, 30 percent of Iceland’s electricity is produced by geothermal sources and most of the rest comes from hydroelectric dams.
Iceland has abundant geothermal energy because it lies on a crack in the Earth’s crust where the North American and Eurasian plates are pulling apart. That makes it very different from the volcanic geothermal energy that lies beneath Hawaii Island, which is generated by a volcanic hotspot, not shifting continental plates. New Zealand, with both active and dormant volcanoes, is a better comparison with Hawaii’s situation.
S: http://www.hawaiibusiness.com/geothermal-is-a-red-hot-topic/ (last access: 10 January 2015)
N: Volcanoes and geothermal energy.
Geothermal energy is plentiful, but geothermal power is not. Temperatures increase below the Earth’s surface at a rate of about 30 °C per km in the first 10 km (roughly 90 °F per mile in the first 6 miles) below the surface. This internal heat of the Earth is an immense store of energy. In the upper 10 km of rock beneath the conterminous United States, it amounts to 3.3 × 1025 joules, or about 6,000 times the energy contained in the world’s oil reserves. The problem in utilizing geothermal energy is extracting it.
S: EncBrit – http://global.britannica.com/EBchecked/topic/632130/volcano/253608/Volcanoes-and-geothermal-energy (last access: 10 January 2015)
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