New geothermal maps show vast potential energy source

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Geothermal energy is hardly new. There is evidence that it was used in the U.S. as early as the 1800s. In 1904, a fellow named Piero Ginori Conti opened the first geothermal plant in Larderello, Italy. It was a dry steam reservoir that was used to generate electricity.

But geothermal, like a lot of alternative energy technologies, barely registers in a nation that still depends mostly on oil and coal. Currently, there is only about 3,000 megawatts of installed geothermal energy capacity in the U.S., according to the Southern Methodist University Geothermal Laboratory. That’s in a nation with a total energy generating capacity, from all sources, of 1 million megawatts.

Now, the SMU laboratory has released a new series of geothermal maps of the U.S. that show a practically limitless source of energy -- if it can be tapped.

David D. Blackwell, a geophysics professor at the lab, said the ‘technical potential’ of what could be tapped was roughly equal to about 3 million megawatts, or three times the nation’s current energy production.

‘The technical potential is our best estimate of what actually might be extracted,’ Blackwell said. ‘The question is, ‘Do we have the will to go ahead and try to really develop it?’’

The new maps, such as the one displayed here at a depth of 6.5 kilometers underground, show heat sources that range from a relatively cool 50 degrees Celsius (about 122 degrees Fahrenheit) to 300 degrees Celsius.

Most of the hottest spots are in the Western U.S., but SMU officials said that newer technologies for tapping geothermal sources could take advantage of cooler hot spots in West Virginia, Texas and along the Gulf Coast.

‘The eastern two-thirds of the country were always dismissed in terms of geothermal potential,’ said Cathy Chickering, an SMU lab geothermal specialist, adding that the newer technologies could produce energy in those areas.

As an example of the new technologies, Pickering cited the Chena Hot Springs in Alaska, where geothermal energy is being produced in water that is 74 degrees Celsius. ‘That’s significantly cooler than the temperatures people think of as necessary for generating geothermal energy. Other technologies can exploit dry heat by injecting water underground.

The maps were funded in part using by a three-year $480,000 grant from Google. They can be viewed here.

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-- Ronald D. White

Graphic: One of the SMU Geothermal Laboratory’s new ‘temperature at depth’ maps of potential new sources of energy. Credit: Courtesy of SMU Geothermal Laboratory.