LOWER SIXTH - KGP SCHEDULE, WEEKS 2-9 - ENERGY
MODULE 1 THE DYNAMICS OF CHANGE
10.2 PEOPLE AND THE ENVIRONMENT -POPULATION AND RESOURCES
RENEWABLE ENERGY - HEP
NON-RENEWABLE ENERGY -OIL
   
GEOTHERMAL
Geothermal energy is the heat that occurs naturally within the earth and can be found stored in rock and water. Near the surface, this energy can be extracted from heated rocks and molten magma in volcanic areas, in places where earthquakes occur, or from hot springs or geysers. Examples include the Pacific Rim, the Mediterranean, New Zealand, Iceland and the Rift Valley (East Africa).
To produce electricity, cold water can be pumped downwards, heated naturally, then returned to the surface as steam in insulated pipes. This can be used to drive turbines which generate electricity, or used directly and immediately for heating purposes. Geothermal energy was first used in 1904 in Tuscany, Italy. It has now been developed as an energy source in locations such as the U.K., Iceland, New Zealand, Japan, U.S.A, and Kenya.
World Examples
In the U.K. at Southampton, a geothermal power station was opened in 1988. The water that is pumped down reaches 76C at a depth of 1700 metres below the surface. When pumped back up to the surface, the water goes to an exchanger to heat water in three large buildings. Any spare electricity left over from running the power station is sold to the electricity grid.

In the U.S.A., the world's largest geothermal power station is in Northern California. Steam from the geysers generated 1400MW in 1991. Throughout the world, installed geothermal capacity in 18 countries was about 5,800 MW in 1990, and as much as 9,000 MW was planned by 1995.
In Kenya, geothermal energy is being used as an alternative to steam and oil-fired power stations, which use imported coal. As the demand for power increases, the supply of geothermal energy can add to the electricity being produced. Also, despite the high capital costs due to the technology involved, geothermal energy is half the cost of oil-fired heating, operating costs are lower, and the life of the station is much greater. The energy is obtained from underground water, heated by the earth in the Rift Valley. By 1999, 15% of Kenya's energy supplies were planned to come from geothermal energy.
Possible Problems
Earth movements can damage power stations.
RENEWABLE ENERGY - HEP
NON-RENEWABLE ENERGY -OIL