In relation to the surface area, most use is currently
made of geothermal energy in Iceland and Switzerland. The prerequisites for this
differ between the two countries:
Iceland is a sparsely populated country
but with a great deal of volcanic activity. Geothermal energy at high temperatures
is used there for heating purposes, as well as for generating electricity.
Switzerland, on the other hand, exhibits only slightly above average geothermal
heat flow density. Here the greater part of exploitation is achieved using heat
Because the geothermal heat flow density is very small, heat stored
in the ground or in bedrock is exploited first of all. As a result of local cooling,
heat flows from the surroundings to replace that removed until such time that
equilibrium is restored. In the course of this, particular attention is to be
paid to long-term sustainability.
Furthermore, questions regarding usage rights
arise and above all in densely-populated areas, since heat extraction occurs across
plots of land or political borders.
The values are based on the Survey of
Energy Resources 2004, published by the World Energy Council WEC. They have been
used with permission of the editor Elsevier, Oxford.