Geothermal energy is naturally occurring thermal energy found within rock formations and the fluid held in thine formations. Geothermal energy is naturally occurring thermal energy found within rock formations and the fluid held in thine formations. In the inner core of the earth, there is a layer of hot and molten rock called ‘magma’ which has temperature as high as 4,000°C. The sources of this heat energy are magnetic or radioactive decay processes occur within the interior of the Earth.
- In geothermal power plant, water to be seeping into the underground over time gains heat energy from the geothermal reservoirs. This water is heated and then sent through a steam turbine where the thermal energy (heat) is converted into electricity through, a generator. The next step in the cycle is cooling the fluid and sending it back to the heat source.
- The injection wells ensure that the water that is drawn up is to be returned to the geothermal reservoir where it regains the thermal energy and this cycle continues.
Advantages of Geothermal Energy
- Geothermal energy is the most versatile and least polluting renewable energy source.
- The power generation levels are higher for direct uses such as space heating, geothermal heat pumps, hot water bath stores, aquaculture, green houses, industrial processes and enhanced oil recovery systems.
- It delivers greater amount of net energy than other conventional or non-conventional energy sources.
- Within the electric supply system, geothermal sources could provide steady base load power with very low variable costs.
- Geothermal energy is relatively inexpensive.
Limitations of Geothermal Energy
- Overall efficiency of power production is low which is about 15% compared to fossil fuel plants.
- The withdrawal of large amounts of heat may result in surface subsidence.
- The steam and hot water gushing out of the earth may contain H2S, CO2, NH3 and radon gas, etc. If these gases are vented out, the air pollution will be a real hazard. These gases are to be removed by chemical action before they are discharged.
- Drilling operation is noisy.
- Large areas are needed for extraction of geothermal energy.