Geothermal Energy

What is Geothermal Energy?

Basically, geothermal energy is the technique of gaining heat as energy source from earth’s surface. In order to produce electricity, most power plants require steam. Geothermal power plants use steam which is produced from hot water tanks discovered far below earth's surface. A turbine is rotated by steam which helps to run a generator for electricity production. Most power plants are using conventional fuels to boil water for steam. Earth’s surface holds huge amount of heat which can produce extremely huge amount of energy than all other natural resources like oil and gas in the world. Predicted heat extraction in geothermal energy is very small in comparison to heat content of earth. So, it is renewable.


Types of Geothermal Power Plant:

Geothermal power plants are of three types. They are - flash steam, binary cycle and small scale power plant.


Flash steam power plants: Here, geothermal tanks of water having temperatures higher than 183°C are used. This hot water flows up with its self-pressure through shafts in the ground. Pressure decreases with its upward flowing and some portion of hot water boils into steam. The steam is then separated from the water and used to rotate the turbine in order to generate power. Any excess water and compressed steam are injected back into the tank which is a significant example of sustainable resource.

Binary cycle power plants: These plants work on water at lower temperatures of about 108°-182°C. In order to boil a working fluid, these plants utilize the heat of hot water which is basically an organic compound having lower boiling point. In the heat exchanger, water fluid is evaporated which helps to rotate a turbine. For reheating, the water is then injected back into the ground. During whole process, working fluid and the water are kept separated. So, there is no possibility of air emissions.

Small-scale power plants: These plants are typically under 5 megawatts. They have good prospect of extensive application in rural areas as well as a distributed energy resource. Distributed energy resource is the diversity of small and flexible power producing technologies which is integrated to develop the process of the electricity delivery system.


Applications of Geothermal Energy:

Long time ago, geothermal energy was used for bathing and space heating. Now, it is known for generating electricity. It can also be used for industrial processes, purification and pumping system.


Benefits of Geothermal Energy:

No fuel is required in geothermal energy and its capital costs are very significant. So, it is very cost effective. It is also environmentally friendly, consistent and sustainable. Historically, geothermal energy is limited to areas close to boundaries of tectonic plate. Many areas of the world are already using geothermal energy as a reasonable and ecological solution. At present, countries like United States, Japan, New Zealand, Italy, Iceland, Mexico, El Salvador, Philippines, Indonesia and Kenya are generating the most electricity from geothermal sources. This technology helps to minimize the dependency on fossil fuels and also reduces the global warming. 




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