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Power from the bowels of the earth |
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Wednesday, 14 March 2007 |
After 10 years, the experimental
geothermal heating project at Soultzsous-
Forêt in northern Alsace is ready to
produce electricity in commercial
amounts.
The project is based at the world’s
oldest exploited oilfield where the Earth’s
crust is particularly thin, making drilling
easier. A pilot power station is to be built
which will produce electricity from 2008.
The contract has been awarded to the
Franco-Italian company Cryostar/
Turboden. The scheme is financed jointly
by the European Union, the Agence de
l’Environnement et de la Maîtrise de
l’Énergie – Ademe – and the German
ministry of the environment. It will finally
test whether pumping water deep into the
earth and bringing it back to the surface
again is a viable undertaking for
producing cheap, environmentally clean
electricity. The benchmark will be whether
the system can continuously bring to the
surface 35 litres of water at 175°C per
second via a closed circuit.
Jacques Graff, co-director of the
European Geothermal Project (GEIE),
commented that the new development was
possible following the successful
completion of three trial drillings at 5,000
metres. He said: “The trials have taught us
to extract calories without causing a
disturbance.” He was referring discreetly
to the rather unsettling tendency of these
experiments to cause minor earthquakes
similar to those experienced at Basel near
another geothermal research site in the
Rhine valley. “At a depth of 5km there
is a pressure limit that should not be
exceeded otherwise we start to move the
rock,” he added.
If the pilot plant is a success the plan
is to build the first full-scale geothermic
power plant capable of supplying
20,000 people with electricity by 2015.
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