What is Geothermal Energy
The word geothermal comes from the Greek words geo (earth) and therme (heat). So, geothermal energy is heat from within the earth. Geothermal energy is a form of renewable energy derived from heat deep in the earth’s crust. Our ancestors knew the value of geothermal energy; they bathed and cooked in hot springs. Today we have recognized that this resource has potential for much broader application. The core of the earth is very hot and it is possible to make use of this geothermal energy. These are areas where there are volcanoes, hot springs, and geysers, and methane under the water in the oceans and seas. Geothermal energy is a process where the Earth’s internal energy is tapped for a variety of uses, including electric power production and the heating and cooling of buildings.
Origin
Geothermal energy is generated in the earth's core, about 4,000 miles below the surface. Temperatures hotter than the sun's surface are continuously produced inside the earth by the slow decay of radioactive particles, a process that happens in all rocks. The earth's crust is broken into pieces called plates. Magma comes close to the earth's surface near the edges of these plates. This is where volcanoes occur. The lava that erupts from volcanoes is partly magma. Deep underground, the rocks and water absorb the heat from this magma. The temperature of the rocks and water get hotter and hotter as you go deeper underground.
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Geothermal Energy In India
In India, Northwestern Himalayas and the western coast are considered geothermal areas. The Geological Survey of India has already identified more than 350 hot spring sites, which can be explored as areas to tap geothermal energy. Satellites like the IRS-1 have played an important role, through infrared photographs of the ground, in locating geothermal areas. The Puga valley in the Ladakh region has the most promising geothermal field. An experimental 1-kW generator is already in operation in this area. It is being used mainly for poultry farming, mushroom cultivation, and pashmina-wool processing, all of which need higher temperature.
Geothermal Energy and Environment
The environmental impact of geothermal energy depends on how it is being used.
- Direct use and heating applications have almost no negative impact on the environment.
- Geothermal power plants do not burn fuel to generate electricity, so their emission levels are very low. They release less than 1 percent of the carbon dioxide emissions of a fossil fuel plant. Geothermal plants use scrubber systems to clean the air of hydrogen sulfide that is naturally found in the steam and hot water. Geothermal plants emit 97 percent less acid rain - causing sulfur compounds than are emitted by fossil fuel plants. After the steam and water from a geothermal reservoir have been used, they are injected back into the earth.
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