What is Geothermal Energy

The rise in price per barrel of oil from US $27-30 in 2000 to US $70-90 today is by far the best reason as to why we need to start looking beyond the conventional sources of energy and invest in alternative sources. Even though the list of alternative energy sources is quite lengthy, we need to critically evaluate these sources before we invest in them. One of the most promising alternative source of energy is geothermal energy, which also boasts of being one of the cleanest source of energy available today. Even though it is quite promising, it does have some disadvantages and we cannot tap it to its full potential unless these disadvantages are sorted out.

Geothermal Energy

As its name suggests, geothermal energy is the energy derived from within the Earth. The word 'geothermal' is derived from a combination of two Greek words geo meaning the Earth and thermos meaning heat. It is tapped by recovering heat from beneath the Earth's crust in the form of steam, and using the same to generate electricity. The presence of this heat in the interior of the Earth can be attributed to many factors including origin of the planet, volcanic activity beneath the Earth's crust, radioactive decay of minerals, etc. Its environment friendliness and relatively low cost make it an apt alternative for replacement of fossil fuels. Whether the entire concept is actually feasible is something that can be determined only after the pros and cons of geothermal energy are evaluated, and to evaluate them one has to get a better understanding of how the entire concept works.

How Does it Work?

As in case of coal plants and nuclear power plants, there also exist geothermal power plants. These geothermal plants generate electricity by harnessing geothermal dry steam or hot water which is derived from within the Earth's crust. This steam or hot water is accessed by digging the ground or by using pipeline to bring the same to the surface of the Earth. On the basis of how the steam or hot water is accessed, geothermal plants are divided into three types - dry steam plants (wherein steam is brought to the surface using a pipeline,) flash steam plants (wherein water is brought to the surface and sprayed into a tank to create steam) and binary cycle plants (wherein certain chemicals are added to hot water derived from the Earth to form steam.) Irrespective of which type of geothermal plant it is, the steam produced is eventually used to rotate turbines, and this rotation of turbines produces electricity.

What is it Used For?

When we talk about geothermal energy application, the first thing that is likely to come to your mind is geothermal heat pump system. The fact that Environmental Protection Agency (EPA), Department of Energy (DOE) and other such agencies have given a thumbs up to these heat pump systems has made them very popular in the United States of America. Other than geothermal heating and cooling systems, this energy is also utilized for heating water in the United States. If the International Geothermal Association (IGA) reports are to be believed, 67,246 GWh of electricity is produced by geothermal power plants all over the world. In the United States of America, alone, there exist as many as 77 power plants which boast of a total installed capacity of 3,086 MW of power generation.

While the advantages of geothermal energy may make it seem quite promising, you also need to take its disadvantages, such as limited locations and unreliability, into consideration. When its advantages and disadvantages are weighed against each other, one can see that we still need to work on certain aspects of this energy source to make it an apt replacement for fossil fuel.