by Graeme » Tue 08 Nov 2011, 18:51:31
Geothermal Energy’s Promise and Problems
$this->bbcode_second_pass_quote('', 'G')eothermal energy is touted as one of the few renewable resources that could be used for base-load (round-the-clock) power generation: Earth’s heat is always on, and it’s not dependent on the vagaries of wind or sun. New research from Southern Methodist University—sponsored by Google’s philanthropic arm—suggests massive potential for geothermal power in the United States. But exploiting that resource will be slowed by the cost of the technology—and the fact that it can cause small earthquakes.
"We know that creating these EGS reservoirs involves making earthquakes. That’s just going to happen," Williams says. "The question then becomes, Are we going to be able to control the process of generating the microseismicity so that we don’t generate earthquakes that are magnitude 3.5 or 4.0 or something like that?" There will likely need to be geographic restrictions on development so that such a potential quake doesn’t occur near a large fault and possibly cause an even bigger quake. The U.S. National Academy of Sciences and the National Academy of Engineering have launched an investigation, looking across many energy technologies; their report is expected in 2012.
After EGS was blamed for a 3.4-magnitude earthquake in Basel, Switzerland, projects in Europe and the United States have struggled to get off the ground. Karl Gawell, the executive director of an industry group called the Geothermal Energy Association, says that the scrutiny now placed on the issue suggests that projects won’t move forward without strong indications of safety. "You won’t see another Basel, Switzerland, at least not in the United States," he says.
For the moment, cost is also a primary barrier to widespread adoption. USGS’s Williams says traditional geothermal electricity is "in the ballpark" in terms of cost with other electricity sources. A 2009 report by the investment bank Credit Suisse quoted a conventional geothermal cost of 3.6 U.S. cents per kilowatt-hour, below the 5.5 cents for coal. EGS is costlier. A 2007 report by consulting firm GeothermEx estimated the best possible cost for EGS systems in the future at 5.4 cents per kilowatt-hour and suggested that the technology won’t be truly cost competitive until 2050. "Until EGS is developed on a wide scale, initially it probably wouldn’t be competitive," Williams says. "Right now we’re looking at sort of slow but steady development."
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Human history becomes more and more a race between education and catastrophe. H. G. Wells.
Fatih Birol's motto: leave oil before it leaves us.