past:
present:
Geothermal Energy
The first geothermal power plant to produce energy was at Lardarello, Italy, in 1904. Geothermal means “heat from the earth” in Greek. Later there will be information about geothermal energy and how they produce electricity; where in the world is it, and some advantages and disadvantages of it. There are three main types of geothermal plants.
Flash steam power plants operate by using tanks
of water with temperatures greater than 360o F. This sweltering
water goes up through wells that are in the ground under its own pressure.
As the water is going up, pressure decreases and some hot water flashes
into high-pressure steam. Then the steam is used to spin a turbine connected
to a generator, which makes electricity. The leftover water and 
condensed
steam goes back to the reservoir, which is a place where they store
water [1].
Dry steam power plants draw from underground resources of water. Steam goes through pipes from wells that are under ground to where the power plant is. Then the steam goes into a turbine, which drives a generator that produces electricity [1].
Binary-cycle power plants work by using water with temperatures
lower than 225o to 360o Fahrenheit. The heat energy
is used from the hot water to boil with operating fluid, usually an
organic compound with a low boiling point. The fluid is vaporized in
a heat 
exchanger and used to spin the turbine; a generator
is attached to the turbine and produces electricity. Then water goes
back into the earth to be reheated. The fluid is kept apart during the
whole process, so there are no emissions or if there is, then it’s very
little of it. All of these three kinds of power plants have magnets
spinning inside a coil of wire in their generators. These plants have
to be in places that have the heated water for geothermal power [1].
Geothermal plants need to be where
the earth’s crust is thin. Geothermal energy is
mostly found along the Pacific Rim, where deep
fractures occur in the earths crust. Some places
that molten material, or magma, pushes close
enough to the surface to heat geothermal reservoirs are in Hawaii, Italy, which has a
great amount of geothermal energy, New Zealand, and the United States. [2]. These
countries have found that there are many benefits in using geothermal energy.
One support of geothermal energy is that it is a renewable resource - it’s clean,
reliable, and easy on the land [2]. A different benefit is that it could produce electricity
without burning any fuels such as gas, coil, or oil and it is available twenty-four hours a
day all year [3]. There are also many drawbacks in using geothermal power.
One shortcoming of geothermal is that the system needs antifreeze to keep the loop water from freezing when the temperature is cold [4]. A different weakness is that every unit needs to have a plumbing and electrical service.
Geothermal energy can be a cheap form of energy those who live in the part of the world that could get into the heated underground water easily. Geothermal energy is a very good source of energy that manufactures electricity very easily without having to pollute. In the future, geothermal is likely to be used the most where it is available, compared to the other energy sources.
Sources
1. “Geothermal electricity production”, National Renewable Energy laboratory
www.nrel.gov/clean_energy/geoelectricity.html
2. “Geothermal energy facts”, Geothermal Education office
www.geothermal.marin.org/pwrheat.html
3. “Geothermal Energy program”, Renewable energy network,
www.eren.doe.gov/geothermal/geofag.html
4. “Geothermal Advantages & Disadvantages”, Geothermal Heat Pump System
http://www.tristate.apogee.net/geo/gdfdgad.htm
5. “Encarta 2002 Microsoft”
CD-ROM.
6. Pictures- http://www.eren.doe.gov/geothermal/geopowerplants.html