Thursday, April 28, 2011

Harnessing Volcanoes Themselves for Energy?

Harnessing Volcanoes Themselves for Energy?: "

A derailed 2009 project in search of improved geothermal resources has been found to have uncovered a new way to harness energy from volcanic magma itself, according to a paper just published at Geology: Origin of a rhyolite that intruded a geothermal well while drilling at the Krafla volcano, Iceland by Wilfred Elders, a professor emeritus of geology in the Department of Earth Sciences at the University of California, Riverside.

An unexpected intrusion of volcanic magma destroyed the original geothermal test, conducted by a consortium of US universities including UCDavis and Stanford, the US and Icelandic governments, including the USGS, and Iceland’s GeoSurvey and Landsvirkjun Power.

Before they could complete the drilling of what was to be 15,000 foot borehole, volcanic magma breached the wall, filling 30 feet at the bottom of the 6,900-foot-deep open borehole, forcing the researchers to terminate the drilling. Instead they turned it into a production well.

However, in the meantime, the turn of events gave them a chance to study the magma and test the volcanic system as an energy source. The magma poured in at temperatures of 1,652 F, which is far hotter than normal geothermal fluids. What they found is promising for other regions with very hot young volcanic rock formation.

Elders believes it should be possible to find reasonably shallow bodies of magma, elsewhere in Iceland and the world, wherever young volcanic rocks occur, and that the economics of generating electric power from such geothermal steam improves the higher its temperature and pressure.

“As you drill deeper into a hot zone the temperature and pressure rise, so it should be possible to reach an environment where a denser fluid with very high heat content, but also with unusually low viscosity occurs, so-called ‘supercritical water’” says Elders. “Although such supercritical water is used in large coal-fired electric power plants, no one had tried to use supercritical water that should occur naturally in the deeper zones of geothermal areas.”

The high-pressure dry steam flowing to the surface from a depth shallower than the magma was heated to 400 C (750 F), the researchers found.

That steam could have a generating capacity of five times that of typical geothermal fluid.


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