'Geo' means 'earth' and 'thermal' means ' heat'. Thus, geothermal energy is the heat energy from hot rocks present inside t earth. This heat can be used as a source of energy to produce electricity. Please note that geothermal is one of t few sources of energy that do not come directly on indirectly from solar energy (or sun's energy).
At some places in t world, the rocks at some depth below the surface of the earth 🌎 are very, very hot. This heat comes from the fisdiiy of radioactive materials which are naturally present in these rocks. The places where very hot rocks occur at some depth below the surface of earth are called 'hot spots', and are sources of geothermal energy.
The geothermal energy is harnessed as follows:
The extremely hot present below the surface of earth heat the underground water and turn it steam. As more and more steam is formed between the rocks, it gets. compressed to high pressures.
A hole is drilled into the earth up to the hot rocks and a pipe is put into it. The steam present around the hot rocks comes up through the turbine of a generator to produce electricity.
Sometimes two holes are drilled into the earth in the earth 🌎 in the region of hot rocks and two pipes are put into them. Cold water is pumped in through one of the pipes. This cold water is turned into steam by the the hot rocks. The steam thus formed comes out through the other pipe and used to generate electricity.
Some of the advantage of using geothermal energy are as follows: It is econmical to use geothermal energy. This is because the cost of electricity produced by using geothermal energy is almost half of that produced from conventional energy sources. Another advantage is that the use of geothermal energy does not cause any pollution.
So, it is a clean and environment friendly source of energy. Some of the disadvantage Of geothermal energy are as follows: Geothermal energy is not available everywhere. It is available only in those areas where there are hot rocks near the earth's surface. Another disadvantage is that deep drilling in the earth to obtain geothermal energy is technically very difficult and expensive.
In our country there are a very limited number of places where geothermal energy can be harnessed on a commercial scale. Two places where geothermal energy can be explained on commercial scale are located in Madhya Pradesh and Himachal Pradesh . In U.S.A and Newzealand, a number of geothermal energy power plants are working successfully.
