Tribe.net. Local Connections iona http://ionaisthebomb.tribe.net/thread/6dfb1065-0442-438c-bdd1-6cb7e01625d3#4870a84f-bc8b-48b4-b306-46f72a09fa22 2007-01-30T21:14:43Z 2007-01-30T21:14:43Z

http://www.boston.com/news/globe/health_science/articles/2007/01/29/the_power_of_rocks/ By Gareth Cook, Globe Staff | January 29, 2007 As the nation searches for environmentally friendly sources of electricity, some researchers say they have an answer: rock power. Article Tools * PRINTER FRIENDLYPrinter friendly * SINGLE PAGESingle page * E-MAILE-mail to a friend * RSS FEEDSHealth / Science RSS feed * RSS FEEDSAvailable RSS feeds * MOST E-MAILEDMost e-mailed * REPRINTS & LICENSINGReprints & Licensing * Share on Facebook * Tag with Del.icio.us Save this article * powered by Del.icio.us More: * Globe Health / Science stories | * Health & Fitness section | * Science section | * Globe front page | * Boston.com * Sign up for: Globe Headlines e-mail | * Breaking News Alerts The continental United States rests on vast slabs of blistering granite heated by the earth's mantle and other geological processes. Using a technology called heat mining, it should be increasingly possible to tap that energy and use it to generate electricity with virtually no pollution. Already the country is the world's leading producer of geothermal power, which taps steam from underground to turn turbines. This renewable resource generates more electricity than wind and solar combined. But geothermal power today is largely restricted to isolated spots in the West where rocks are hot at relatively shallow depths. Heat mining -- which takes advantage of advances in drilling and geological understanding -- could make geothermal power practical across much broader swaths of the country. "What was thought to be impossible 10 years ago is now possible," said Roy Baria , a British geophysical consultant. "The technology has moved significantly." Related stories from today's Globe Scientists protest draft of global warming report The power of rocks E.O. Wilson sees accord on climate action GLOBE EDITORIAL: When science isn't Last week the Massachusetts Institute of Technology released a study concluding that heat mining could generate enough energy by 2050 to replace the coal-fired and nuclear power plants that are likely to be retired over the next several decades. While the nation has focused on higher-profile technologies like wind power, scientists say innovative projects overseas show that the United States has a vast and largely overlooked underground treasure. "The public needs to understand that these are not just Western resources," said Joseph Moore , who was not involved in the MIT study and is a research professor at the Energy and Geoscience Institute at the University of Utah . "And unlike wind and solar, it is always available on demand." All geothermal systems are built on a simple fact : The deeper you go, the warmer it gets. More and more homes and businesses are tapping into that warmth, using it to save on their heating bills by installing heat pumps connected to relatively shallow wells. But it takes much higher temperatures and deeper wells to generate electricity efficiently. Power companies have traditionally placed plants at hydrothermal sites: geologically active places with plenty of water percolating through shattered rock, where simply drilling a well will bring up large amounts of steam. These hydrothermal sites are relatively rare, though, while hot rock is everywhere. With heat mining, engineers tap the massive amounts of heat energy stored in this deep rock, away from natural hydrothermal sites. In theory, this is straightforward. Engineers drill a deep well into hot rock. They pump down water under very high pressure to expand cracks in the rock, creating a chamber where water can flow and absorb the rock's heat. Finally, they drill another well to tap the superheated water.Continued...

iona 2007-01-30T21:14:43Z