Geothermal Energy
Geothermal energy is a source of energy that comes from heat deep below the surface of
the Earth. This heat produces hot water and steam from rocks that are heated by magma.
Power plants that use this type of energy get to the heat by drilling wells into these rocks.
The hot water or steam comes up through these wells. Then, the hot water or steam makes
a turbine spin to make electricity. Because the hot water or steam can be used directly to
make a turbine spin, geothermal energy is a resource that can be used without processing.
The fact that it does not need to be processed makes geothermal energy different from most
other energy resources. Geothermal energy is clean and safe. It is renewable, too, because
the power plant can pump the hot water back into the underground pool. There, the water
can pick up heat to make more steam.
This source of energy is an excellent resource in some parts of the world. For example,
Iceland is a country that gets about one fourth of its electricity from geothermal sources. In
the United States, California leads all states in producing geothermal energy. Geothermal
energy in California is concentrated in a few areas in the northern part of the state. The
largest geothermal power plant in the state is in the Geysers Geothermal Resource Area in
Napa and Sonoma Counties. The source of heat is thought to be a large magma chamber
lying beneath the area, a part of the Pacific Ring of Fire. Many parts of the world do not
haveundergroundsourcesofheatthatarecloseenoughtothesurfaceforbuildinggeothermal
power plants.
Lesson Summary
- Solar energy, water power, wind power, biomass energy and geothermal energy are
renewable energy sources. - Solar energy can be used either by passively storing and holding the sun’s heat, con-
verting it to electricity or concentrating it. - There are many ways to use the energy of moving water including hydroelectric dams.