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 pumps.
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.
