[Editors] MIT releases major report on geothermal energy

[Patti Richards]

MIT News Office
Massachusetts Institute of Technology
Room 11-400
77 Massachusetts Avenue
Cambridge, MA  02139-4307
Phone: 617-253-2700
http://web.mit.edu/newsoffice/www

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MIT releases major report on geothermal energy
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For Immediate Release
MONDAY, JAN. 22, 2007
Contact: Patti Richards
Phone: 617-253-8923
Email: prichards at mit.edu

PHOTO AVAILABLE

CAMBRIDGE, Mass.--A comprehensive new MIT-led study of the potential 
for geothermal energy within the United States has found that mining 
the huge amounts of heat that reside as stored thermal energy in the 
Earth's hard rock crust 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.

An 18-member panel led by MIT prepared the 400-plus page study, 
titled "The Future of Geothermal Energy." Sponsored by the U.S. 
Department of Energy, it is the first study in some 30 years to take 
a new look at geothermal, an energy resource that has been largely 
ignored.

The goal of the study was to assess the feasibility, potential 
environmental impacts and economic viability of using enhanced 
geothermal system (EGS) technology to greatly increase the fraction 
of the U.S. geothermal resource that could be recovered commercially.

Although geothermal energy is produced commercially today and the 
United States is the world's biggest producer, existing U.S. plants 
have focused on the high-grade geothermal systems primarily located 
in isolated regions of the west. This new study takes a more 
ambitious look at this resource and evaluates its potential for much 
larger-scale deployment.

"We've determined that heat mining can be economical in the short 
term, based on a global analysis of existing geothermal systems, an 
assessment of the total U.S. resource and continuing improvements in 
deep-drilling and reservoir stimulation technology," said panel head 
Jefferson W. Tester, the H. P. Meissner Professor of Chemical 
Engineering at MIT.

"EGS technology has already been proven to work in the few areas 
where underground heat has been successfully extracted. And further 
technological improvements can be expected," he said.

The expert panel offers a number of recommendations to develop 
geothermal as a major electricity supplier for the nation. These 
include more detailed and site-specific assessments of the U.S. 
geothermal resource and a multiyear federal commitment to demonstrate 
the concept in the field at commercial scale.

The new assessment of geothermal energy by energy experts, 
geologists, drilling specialists and others is important for several 
key reasons, Tester said.

First, fossil fuels--coal, oil and natural gas--are increasingly 
expensive and consumed in ever-increasing amounts. Second, oil and 
gas imports from foreign sources raise concerns over long-term energy 
security. Third, burning fossil fuels dumps carbon dioxide and other 
pollutants into the atmosphere. Finally, heat mining has the 
potential to supply a significant amount of the country's electricity 
currently being generated by conventional fossil fuel, hydroelectric 
and nuclear plants.

The study shows that drilling several wells to reach hot rock and 
connecting them to a fractured rock region that has been stimulated 
to let water flow through it creates a heat-exchanger that can 
produce large amounts of hot water or steam to run electric 
generators at the surface. Unlike conventional fossil-fuel power 
plants that burn coal, natural gas or oil, no fuel would be required. 
And unlike wind and solar systems, a geothermal plant works night and 
day, offering a non-interruptible source of electric power.

Prof. Tester and panel member David Blackwell, professor of 
geophysics at Southern Methodist University in Texas, also point out 
that geothermal resources are available nationwide, although the 
highest-grade sites are in western states, where hot rocks are closer 
to the surface, requiring less drilling and thus lowering costs.

The panel also evaluated the environmental impacts of geothermal 
development, concluding that these are "markedly lower than 
conventional fossil-fuel and nuclear power plants."

"This environmental advantage is due to low emissions and the small 
overall footprint of the entire geothermal system, which results 
because energy capture and extraction is contained entirely 
underground, and the surface equipment needed for conversion to 
electricity is relatively compact," Tester said.

The report also notes that meeting water requirements for geothermal 
plants may be an issue, particularly in arid regions. Further, the 
potential for seismic risk needs to be carefully monitored and 
managed.

According to panel member M. Nafi Toksöz, professor of geophysics at 
MIT, "geothermal energy could play an important role in our national 
energy picture as a non-carbon-based energy source. It's a very large 
resource and has the potential to be a significant contributor to the 
energy needs of this country."
Toksöz added that the electricity produced annually by geothermal 
energy systems now in use in the United States at sites in 
California, Hawaii, Utah and Nevada is comparable to that produced by 
solar and wind power combined. And the potential is far greater 
still, since hot rocks below the surface are available in most parts 
of the United States.

Even in the most promising areas, however, drilling must reach depths 
of 5,000 feet or more in the west, and much deeper in the eastern 
United States. Still, "the possibility of drilling into these rocks, 
fracturing them and pumping water in to produce steam has already 
been shown to be feasible," Toksöz said.

Panel member Brian Anderson, an assistant professor at West Virginia 
University, noted that the drilling and reservoir technologies used 
to mine heat have many similarities to those used for extracting oil 
and gas. As a result, the geothermal industry today is well connected 
technically to two industry giants in the energy arena, oil and gas 
producers and electric power generators. With increasing demand for 
technology advances to produce oil and gas more effectively and to 
generate electricity with minimal carbon and other emissions, an 
opportunity exists to accelerate the development of EGS by increased 
investments by these two industries.

Government-funded research into geothermal was very active in the 
1970s and early 1980s. As oil prices declined in the mid-1980s, 
enthusiasm for alternative energy sources waned, and funding for 
research on renewable energy and energy efficiency (including 
geothermal) was greatly reduced, making it difficult for geothermal 
technology to advance. "Now that energy concerns have resurfaced, an 
opportunity exists for the U.S. to pursue the EGS option aggressively 
to meet long-term national needs," Tester observed.

Tester and colleagues emphasize that federally funded engineering 
research and development must still be done to lower risks and 
encourage investment by early adopters. Of particular importance is 
to demonstrate that EGS technology is scalable and transferable to 
sites in different geologic settings.

In its report, the panel recommends that:

* More detailed and site-specific assessments of the U.S. geothermal 
energy resource should be conducted.
* Field trials running three to five years at several sites should be 
done to demonstrate commercial-scale engineered geothermal systems.
* The shallow, extra-hot, high-grade deposits in the west should be 
explored and tested first.
* Other geothermal resources such as co-produced hot water associated 
with oil and gas production and geopressured resources should also be 
pursued as short-term options.
* On a longer time scale, deeper, lower-grade geothermal deposits 
should be explored and tested.
* Local and national policies should be enacted that encourage 
geothermal development.
* A multiyear research program exploring subsurface science and 
geothermal drilling and energy conversion should be started, backed 
by constant analysis of results.

About this study:
In addition to Tester, Blackwell, Toksöz and Anderson, members of the 
geothermal panel include: Geomechanics expert Anthony Batchelor, 
managing director of GeoScience Ltd. in the United Kingdom; reservoir 
engineer Roy Baria from the United Kingdom; geophysicists Maria 
Richards and Petru Negraru of Southern Methodist University; 
mechanical engineer Ronald DiPippo, an emeritus professor at the 
University of Massachusetts at Dartmouth; risk analyst Elisabeth 
Drake of MIT; chemist John Garnish, former director of geothermal 
programs of the European Commission; drilling expert Bill Livesay; 
economist Michal Moore of the University of Calgary in Canada, former 
California energy commissioner and chief economist at the National 
Renewable Energy Laboratory; commercial power conversion engineer 
Kenneth Nichols; geothermal industry expert Susan Petty; and 
petroleum engineering consultant Ralph Veatch Jr. Additional project 
support came from Chad Augustine, Enda Murphy and Gwen Wilcox at MIT.