Thursday, April 12, 2007

Geothermal power for the entire U.S.

From the Energy Blog...

The following is a summary—newly posted on the Energy Blog—of claims made by MIT's Jefferson Tester and his team that studied the capacity of geothermal energy in the U.S.

  • Geothermal resources are available nationwide, although the highest-grade sites are in western states.
  • Geothermal energy using enhanced geothermal system (EGS) technology would greatly increase the fraction of the U.S. geothermal resource that could be recovered commercially.
  • The United States, generating 300 megawatts, is already the biggest producer of geothermal.
  • If geothermal is going to be anything more than a minor curiosity, it has to reach at least the level of hydro and nuclear power, or 100,000 megawatts out of 1 million—one-tenth of total capacity," he said.
  • The study found that geothermal could supply a substantial portion of the electricity the United States will need in the future, probably at competitive prices and with minimal environmental impact.
  • The process involves drilling to as deep as 30,000 feet, pumping water under pressure into fractures to break apart underground rock formations and freeing up reservoirs.
  • Seismic activity is a risk, he said. "The big challenge is to show you can do it not only in California, but also in the Midwest and ultimately on the East Coast, where you have to go deeper."
  • Among geothermal's advantages are its below-ground, out-of-sight nature, making it easier to site, and its high capacity and because, unlike solar or wind, it runs a the time. Environmental impacts are "markedly lower than conventional fossil-fuel and nuclear power plants."
  • Meeting water requirements for geothermal plants may be an issue, particularly in arid regions."
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