The Low Carbon Partnership
Solar Power
Geothermal Energy
Geothermal power plants harness the energy from the natural heat of the Earth.
This
geothermal heat is very close to the Earth’s surface in some places (such
as volcanoes and hot springs), but elsewhere it can be several miles
down into the ground. Geothermal energy is a reliable renewable resource
because heat is always being produced by the Earth. It is a clean source
of energy as no fuel is burned and therefore no carbon dioxide is released
into the air.
Dry steam power plants at The Geysers in California
Source: The Office of Energy Efficiency and Renewable Energy, US Department of Energy
www1.eere.energy.gov/geothermal/powerplants.html
The first geothermal power plant was a dry steam plant built in 1904
in Italy. Today there are similar plants in New Zealand, Japan, Iceland
and the USA. Steam technology is still used today at The Geysers in California,
which is the world's largest single source of geothermal power.
Different types of power plant can be used depending on the temperature and pressure of the geothermal reservoir. In dry steam plants, the geothermal energy is extracted by drilling wells deep into the ground where the Earth’s crust is fractured. The heat in the Earth below causes steam to rise up the well, which passes through turbines that generate electricity. The water is then injected back into the ground to be heated again. These plants emit only steam and very small amounts of gases.
Source: The Office of Energy Efficiency and Renewable Energy (EERE), US Department of Energy
