The electrical energy production from geothermal power plants in Europe comes almost
entirely from Iceland, Italy, Russia (Kamtchatka and Kurili islands), France
(Guadeloupe, French West Indies), Portugal (Azores) and Turkey. Installed generating
capacity are respectively 202, 790, 79, 15, 16 and 20.4MWe. The temperatures are
190-320ºC, 150- 350ºC, 200-300ºC, 250ºC, 250ºC and 140-240ºC, respectively. The
percentage with respect
to their National Energy is 16.6% for Iceland, 1,9% for Italy, 9% for France (only
referred to Guadeloupe Island), 25% for Portugal (only referred to San Miguel
Island), while it is ranked negligible for Russia and Turkey.
Exploited reservoir depths range from shallow in Guadeloupe, Azores (0.3-1.1km) to
medium in Iceland, Russia and Turkey (1-2km) to deep in Italy (1.5-4km). In most
cases the permeability is defined by fractures and faults, which are difficult to
locate prior drilling.
Although some of these geothermal areas are among the most important in the world,
they are probably not used at their maximum efficiency. EGS technology may enhance
production from conventional high enthalpy fields, and is used only to a certain
extent in some of these areas.
EGS methods that could be applied are various. Well stimulation methods to improve
permeability of poor-producer wells; tracer tests and improved geophysical imaging to
determine the extent of faulted reservoirs and prevent strong interference between
wells; complete reservoir modelling; efficient scale inhibitors to prevent scaling in
wells and surface pipes. All these are examples of goals that should be addressed in
high enthalpy systems in the near future, in order to increase the contribution of
geothermal power generation in Europe.
A review of the main characteristics of these geothermal areas will be given, as well
as a discussion of their EGS potentiality.