Stimulated geothermal
systems
Detailed information
Technological principle with history
The principle was already used 30 years ago by a national research lab
in new Mexico (USA). The project was stopped however before the
construction of a power plant. Later on, test plants were built in Great
Britain, in Germany and in Japan. Then the european research project in
Soultz sous Forêts (Alsace, France) followed. Also in the desert of
Australia several drillings were already provided, in order to build a EGS
power plant. The interest in this technology increased world-wide.
Challenges of the overall system
The past research and development in the area of the deep Geotherm
concentrated primarily on questions, which concern resources and their
development, i.e. particularly on geology, the drilling technics and the
creation of the necessary water circulation, also on the production of a
reservoir etc.. Beside questions of the transformation and use of the won
geothermal warmth play a just as important role. The procedures to the
generation of electricity from warmth lower to middle temperature, are
well-known in principle, since they are used in another place already for
years in geothermal power stations in addition, other plants, e.g. for the
use of the industrial -heatwaste or -biomass.
The use of the geothermal warmth exhibits however different
characteristics, which can have a large influence on the system choice. As
important aspect, the fact that the use temperature decreases over the
life span of a geothermal system, eventhough in principle the warmth is
flowing and renewing. Besides losses of water as well as loss of pressure
are possible in the primary cycle with the EGS concept. Thus high
achievements of the circulating pumps are required. The mass throughput
and thus thermal achievements are limited.
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