A EURASIAN LOOK AT GEOTHERMAL

Claims Geothermal Energy Is Solution For Future
7 September 2010 (Eurasia Review)

"…Geothermal heat offers incredible potential. It is an inexhaustible energy source that is nearly emission-free. Heat energy is found in the different rock types that make up the Earth’s surface, and deeper in the crust. The deeper you get, the hotter it is…Around one-third of the heat flow comes from the original heat in the Earth's core and mantle (the layer closest to the Earth's crust). The remaining two-thirds originate in radioactivity in the Earth's crust…The heat is transported to rock layers that are nearer the Earth's surface…

"Geothermal energy that comes from 150-200 metres below the surface is called low temperature geothermal energy. At these depths…[heat] can be extracted with heat pumps, combined with an energy well. This type of geothermal energy is exploited at a fairly large scale."

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"The Norwegian company Rock Energy wants to be an international leader in geothermal heat and energy. A pilot plant has been planned for Oslo that will collect heat from 5500 metres deep. Temperatures from this depth…can be used in district heating plants…The normal lifespan for a well like this is approximately 30 years. After that the rock will be so cooled by the cold water that has been injected into the wells that it will no longer produce enough heat. However, after 20-30 years, the heat will have built up again, and the well can be used once more…

"…[T]o reduce CO2 emissions and provide clean energy on a scale that will make a difference, we will need go much further down into the Earth itself…[R]esearchers’ goal is to reach depths of 10,000 metres or more to exploit deep geothermal heat. Drilling that deep will enable wells to reach what is called supercritical water with a temperature of at least 374 degrees C and a pressure of at least 220 bar. That multiplies by a factor of 10 the amount of energy you can extract…and the amount of geothermal energy produced can match that created in a nuclear power plant…[but geothermal] heat does not create radioactive waste…"

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"Today's oil companies are making a good living by extracting oil that is as deep as 5000 metres, where temperatures are as high as 170 degrees C. Drilling any deeper than this results in a range of engineering problems…The Norwegian drilling and oil and gas industries all demand equipment that makes it possible to drill ever deeper at an affordable cost…

"One of the unique aspects of geothermal heat is that it is found everywhere throughout the world…How far down you have to drill into the Earth’s crust to reach the temperature that you’re interested in varies from country to country. This is because the crust varies in thickness…The United States, the Philippines, Mexico, Indonesia and Italy are the international leaders in terms of producing electricity from geothermal energy…"