Short essay on Geothermal Energy

Geothermal energy is the heat energy stored beneath the surface in the form of hot spring! And geysers it is the exploitation of heat energy of earth within the upper 10 km of the earth crust. Heat from the molten core of the earth offers a huge and sustainable energy source.

Origin:

The limitless heat from the interior of earth is used to convert water into steam. In volcanic regions of the earth, the hot rock is relatively close to the surface. Also in such regions sometimes, the natural groundwater comes in contact with the hot rock and the heated water or steam may find its way to the surface through natural steam vents.

In such regions, holes can be drilled into the hot rock groundwater structure and make the rising steam to drive turbo generators to produce electric power.

Uses:

We utilise this type of heat for power generation. For developing countries, the overall’ projected potential was estimated at 400×1018 joule for geothermal energy with the projected capacity in 1990. Efforts are being made to use this energy for generating power and creating refrigeration. Geothermal energy can either be used to produce electricity in power station or can be used directly as primary heat.

Advantages:

The green house gas emissions of geothermal stations are much less than that of coal burning power stations. In Ohaake in New Zealand about 320 gm of C0₂ is produced for each KW hour of electricity produced against 950 to 960 gm. if coal was used.

Limitations

Geothermal energy is a proven economical resource with energy technology. It has some environmental problems:

1. The steam brings hydrogen sulphide gas to the surface and pollutes the air unless controls are instituted.

2. Water contains many salts and minerals capable of causing water pollution.

3. The earth in a geothermal field may subside as the water is pumped out.

Suitable Areas and Possibilities

Geothermal energy is fast emerging as a significant source of electricity in several countries, mainly in the Indian oceans and the Pacific region. Indonesia is setting up two geothermal power plants, each of 55 MW capacities in Java.

Geothermal energy accounts for eight per cent of New Zealand’s installed power capacity. France as well as Germany is also using geothermal energy for domestic heating. In Iceland, geothermal energy provides heating and hot water for more than 85 per cent of the houses.

The world’s largest geothermal energy production facilities exist at a location known as “The Geysor” near San Francisco in US. As early as 1904 underground steam was trapped at Larderello, Italy and used as a heat source in generating electricity about 300 geothermal plants at the Geysers, north of San Francisco, California, Italy and U.S.A. are the largest users of geothermal energy today. Other users are New Zealand, Japan and Mexico.

At present, nearly 350 geothermal hot springs have been located in the country. India’s most promising geothermal field is Puga Valley in Ladakh. As Ladakh has no energy resources like coal, petroleum etc., harnessing of geothermal energy has been engaging the attention of scientists from RRL, Jammu who have successfully used this energy for extraction and refining of borax, sulphur and salt in the valley, besides demonstrating its use for space heating.

Another ongoing project for effective utilisation of geothermal energy is a 5 Kw. pilot power plant at Manikaran, and using F-113 as working fluid, the plant has been successfully run at full load of 5 KW under simulated conditions at NAL and installed at Manikaran. Other areas to be screened are in Tattapani (Surguja District (C.G.)), Combay basin (Alakhnanda Valley (U.P.)) and Parvati Valley (H.P.). The thermal manifestation was spread in about 10,000 square metres with the highest temperature being 98.5°C. There are in all 12 different regions in M.P., some of them are Satna, Rewa, Sidhi, Jabalpur and Itarsi etc.