Two University of Minnesota researchers have developed technology that
solves one problem--the proliferation of atmospheric carbon dioxide
(CO2)--to work improving another: how to more efficiently tap the heat
inside the earth for geothermal energy systems.
Earth sciences faculty member Martin Saar and graduate student Jimmy
Randolph have applied for a patent and plan to form a startup company
to commercialize the technology, according to a press release.
The CO2-plume geothermal system (CPG) uses high-pressure CO2, rather
than the conventional water, to carry the heat from deep in the earth.
CO2 travels more easily through porous rock and can extract heat more
readily, according to the researchers. The research was published in the
most recent issue of Geophysical Research Letters.
The technology was "born in a flash of insight on a northern Minnesota
road trip," according to the release, as the two conducted separate
research on geothermal energy capture and geologic CO2 sequestration.
"We connected the dots and said, 'Wait a minute--what are the
consequences if you use geothermally heated CO2?'" states Saar through
the press release.
The consequences, according to Randolph, include being able to capture
heat "in areas you couldn't even think about doing regular geothermal
for electricity production," Randolph says in the release, stating that
the technology could double efficiency in some areas.
The research was jump-started with a $600,00 grant in 2008 from the university's Institute on the Environment's Initiative for Renewable Energy and the Environment
The grant came from an annual pool of $5 million from Xcel Energy's
Renewable Development Fund. IREE disburses a number of grants each year
through a competition, says Rod Larkins, IREE's associate director.
That funding leveraged another $1.5 million grant from the U.S.
Department of Energy, and the researchers are hoping to receive an even
larger grant, says Larkins, which would require a 20 percent match, of
which IREE would cover half (10 percent of the grant amount). That
funding would help move the technology into the pilot phase, according
to the release.
Saar called the IREE grant "really critical" in the release. "I think
it's fair to say that there's a good chance that it wouldn't have gone
anywhere without IREE support in the early days," he says.
Larkins says IREE's interest in funding the research stems from the fact
that the technology reduces a waste stream in achieving its main
objective of capturing heat for geothermal energy.
Source: Rod Larkins, Initiative for Renewable Energy and the Environment
Writer: Jeremy Stratton