The
International Geothermal Association (IGA) has reported that 10,715 megawatts
(MW) of geothermal power in 24 countries is online, which is expected to
generate 67,246 GWh of electricity in 2010.
This represents a 20% increase in online capacity since 2005. IGA projects
growth to 18,500 MW by 2015, due to the projects presently under consideration,
often in areas previously assumed to have little exploitable resource.
In
2010, the United States led the world in geothermal electricity production with
3,086 MW of installed capacity from 77 power plants. The largest group of
geothermal power plants in the world is located at The Geysers, a geothermal
field in California. The Philippines is the second highest producer, with 1,904
MW of capacity online. Geothermal power makes up approximately 18% of the
country's electricity generation.
|
COUNTRY |
CAPACITY (MW) 2007 |
CAPACITY (MW) 2010 |
PERCENTAGE OF NATIONAL PRODUCTION |
|
USA |
2687 |
3086 |
0.3% |
|
Philippines |
1969.7 |
1904 |
27% |
|
Indonesia |
992 |
1197 |
3.7% |
|
Mexico |
953 |
958 |
3% |
|
Italy |
810.5 |
843 |
1.5% |
|
New Zealand |
471.6 |
628 |
10% |
|
Iceland |
421.2 |
575 |
30% |
|
Japan |
535.2 |
536 |
0.1% |
|
Iran |
250 |
250 |
|
|
El Salvador |
204.2 |
204 |
25% |
|
Kenya |
128.8 |
167 |
11.2% |
|
Costa Rica |
162.5 |
166 |
14% |
|
Nicaragua |
87.4 |
88 |
10% |
|
Russia |
79 |
82 |
|
|
Turkey |
38 |
82 |
|
|
Papua-New Guinea |
56 |
56 |
|
|
Guatemala |
53 |
52 |
|
|
Portugal |
23 |
29 |
|
|
China |
27.8 |
24 |
|
|
France |
14.7 |
16 |
|
|
Ethiopia |
7.3 |
7.3 |
|
|
Germany |
8.4 |
6.6 |
|
|
Austria |
1.1 |
1.4 |
|
|
Australia |
0.2 |
1.1 |
|
|
Thailand |
0.3 |
0.3 |
|
|
TOTAL |
9,981.9 |
10,959.7 |
|
Geothermal
electric plants were traditionally built exclusively on the edges of tectonic
plates where high temperature geothermal resources are available near the
surface. The development of binary cycle power plants and improvements in
drilling and extraction technology enable enhanced geothermal systems over a
much greater geographical range. Demonstration projects are operational in
Landau-Pfalz, Germany, and Soultz-sous-Foręts, France, while an earlier effort in Basel,
Switzerland was shut down after it triggered earthquakes. Other demonstration
projects are under construction in Australia, the United Kingdom, and the
United States of America.
The
thermal efficiency of geothermal electric plants is low, around 10-23%, because
geothermal fluids do not reach the high temperatures of steam from boilers. The
laws of thermodynamics limits the efficiency of heat engines in extracting
useful energy. Exhaust heat is wasted, unless it can be used directly and
locally, for example in greenhouses, timber mills, and district heating. System
efficiency does not materially affect operational costs as it would for plants
that use fuel, but it does affect return on the capital used to build the plant.
In order to produce more energy than the pumps consume, electricity generation
requires relatively hot fields and specialized heat cycles. Because geothermal
power does not rely on variable sources of energy, unlike, for example, wind or
solar, its capacity factor can be quite large – up to 96% has been
demonstrated. The global average was 73% in 2005.