Mining heat from the earth? New technology shows promise.
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Here's one vision for easing America's energy and emissions woes: Hundreds of drilling rigs are deployed throughout the country. But they're not prospecting for oil; they're looking for underground rock hot enough to produce steam-driven electricity. The potential? Enough power to provide 10 percent of US electricity by 2050 – with near-zero emissions of greenhouse gases.Skip to next paragraph
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That's the promise of "enhanced geothermal systems," or EGS, says a recent report by the Massachusetts Institute of Technology in Cambridge, Mass.
There are just two major catches. First, about $800 million in research and development is needed over the next decade to make the drilling technology cost-effective. Second, the Department of Energy is trying to kill the program by ending its funding.
On Monday, the DOE unveiled a $24.3 billion fiscal 2008 budget with more funding for nuclear power, alternative fuels, and science programs – but nothing for geo- thermal.
"The department will conduct our own internal review and assessment of the [MIT] report and its recommendations," DOE spokesman Craig Stevens said in an e-mail. But geothermal energy has "already entered the mainstream," he added. The DOE aims to fund new technologies.
Some parts of the technology are indeed mature. For years, conventional geothermal technology has been tapping mostly hot springs formations in a few isolated locations in the Western US, providing about 0.3 percent of the nation's electricity. The newer, enhanced approach identified by MIT could be developed virtually anywhere.
"It appears that large areas of the United States are suitable for future geo- thermal exploitation in the near term that have not been considered in the past," states the recent report, sponsored by the DOE and written by an 18-member panel convened by MIT. "Most of the key technical requirements to make [it] work economically over a wide area of the country are in effect, with remaining goals easily within reach."
The report, released Jan. 22, corroborates other reports – by the National Renewable Energy Laboratory last year and the Western Governors Association in 2005 – of a massive "deep geothermal" resource.
"We should give strong credence to the MIT report," says Dan Reicher, former assistant secretary for energy efficiency and renewable energy in the Clinton years. "With these deep resources, we have the potential to access new energy over most of the country, including the East Coast. This is the moment to be adding to, not cutting, the geothermal R&D budget."
Since the 1970s, a few EGS systems have been tested in a half-dozen places in the US, and test systems are now being developed in France and Australia. The EGS promise has grown along with advances in oil and gas drilling technology and US-industry research partnerships.
Unlike drilling for oil, often done in softer, permeable rock, the enhanced geo- thermal approach requires boring down one to six miles into solid rock. Power plants would inject water down one well, passing it through crevices in the hot rock, then extract steam through another well. Federal research should focus on drilling, rock fracturing, and thermal energy conversion technologies, advocates say.
That's because the cost of digging wells can be as much as 60 percent of the total capital investment of a 25- to 100-megawatt geothermal plant, the MIT study says. Today, drilling a 23,000-foot-deep well into New Hampshire granite would cost about $15 million and take nearly half a year, the report estimates. By contrast, drilling a 15,800-foot-deep oil well in 2004 cost $7.5 million on average, the report says. Advocates say more research could dramatically reduce drilling costs.
"One and all, these recent reports agree there is an enormous resource out there [that] we're still learning how to use," says Karl Gawell, executive director of the Geo- thermal Energy Association, a Washington trade group. "That's why it's so ironic when the White House and DOE say, 'Hey, we're done. There's nothing out there left to learn.' It totally contradicts what the studies are saying."
Geothermal's research budget at DOE was $24 million in fiscal 2006 – the smallest among major federal renewable energy research. But at White House budget office urging, the department eliminated geothermal funding for 2007.
In response, Congress last fall voted to restore at least $5 million to keep the program alive. Last week, Congress moved to add $300 million to the DOE's Office of Energy Efficiency and Renewable Energy – but left it up to the department to allocate some of those 2007 funds to geothermal. Now there is growing concern it won't happen.
"The administration has been surprisingly hostile to geothermal energy research development and deployment," Senate majority leader Harry Reid wrote in a Feb. 1 letter to Energy Secretary Samuel Bodman, obtained by the Monitor. Calling the zero budget for EGS in fiscal 2007 "counterproductive," Senator Reid asked the DOE to restore funding to at least 2006 levels and to assure Congress of continued funding. "Geothermal has the potential to cleanly and renewably satisfy the new electricity needs of the West," he wrote.
With such funding, the cost of enhanced geothermal power could fall from 8 to 9 cents a kilowatt hour today to less than 5 cents as the technology is deployed, making it competitive even with big coal-fired power plants, the MIT report says. Because EGS emits little carbon dioxide, it could become competitive with coal power if regulation makes carbon emissions costly.
One possible result: Geothermal plants could supply about 100,000 megawatts – the equivalent of 200 big coal-burning power plants – by 2050, according to the report. That power could help replace the 50,000 megawatts of coal-fired power and 40,000 megawatts of nuclear power that the US is expected to lose over the next 25 years as it closes old power plants.