Geothermal energy is a clean and renewable source of energy that comes from the magma typically found underneath the earth's surface. Specifically, the heat of the magma is indirectly utilized to generate large amounts of electricity using modern technology.
Geothermal Power Plants
Geothermal power plants have a definite advantage over other types of energy production mechanisms in terms of cleanliness and abundance. Since only naturally occurring steam and hot water are needed to generate electricity, almost no hazardous materials are produced by such facilities.
As of today, there are 3 main types of geothermal plants. One is called the dry-steam geothermal power plant. This type of geothermal power plant makes use of steam as it naturally occurs underground. Another type is called a flash plant, where very hot water (usually at 200 degrees Celsius) is taken up from underneath the ground; water and steam are separated and the steam is used to spin the turbines that generate electricity. The third type of geothermal power plant is called a Binary power plant. This type of geothermal power plant uses the hot water found below the ground to heat a working liquid through heat exchangers. The heated working liquid is used to spin the blades of the turbine.
History of Geothermal Energy
Records show that the early use of geothermal energy could be dated back 10,000 years ago when the Paleo-Indians of North America used hot springs to cook their food. Such hot springs were also used for temperature control purposes. It should also be noted that early humans bathed in hot springs.
The late 18th century marked the time when geothermal energy was harnessed in a larger scale and for industrial purposes. A field in Pisa, Italy (today known as the Larderello fields) was used for the extraction of Boric acid that could be found in hot pools. In 1904, with the hopes of solving problems with an electricity provider, Prince Pierro Conti (owner of the Lardello fields) decided to install a generator was driven by the steam from a well found on his field. Prince Pierro Conti's "steam-powered" generator led to the construction of the first geothermal power plant in 1913. The said power plant had a capacity of 250 kilowatts and, by 1975, a capacity of 405 megawatts.
How Geothermal Energy Works
Geothermal power plants mainly depend on steam to be able to produce electricity. Geothermal power plants use naturally occurring heat to produce steam which could turn generator turbines. Other power plants, on the other hand, burn fossil fuels such as coal or other petroleum products to generate steam.
Geothermal plants vary in the process of producing electricity, though. The dry steam type uses steam directly from an underground source. The flash type uses hot water from a well; steam is separated from the water and only the steam is used to spin the turbine. The binary type also uses hot water, not to generate steam but to heat liquid that would become the driving force for electricity generators.