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The Thermal energy produced and kept in the earth is known as geothermal energy. It is the thermal energy produced by radioactive decay and ongoing earth formation heat loss. The earth’s geothermal energy is more than enough to meet all of humanity’s energy demands, but only a small portion can be used in a way that is profitable. Geothermal energy is derived from the Earth’s natural heat. The decay of naturally radioactive isotopes of uranium, thorium, and potassium produces geothermal energy. Heat is transmitted from the Earth’s core to the surface due to a large temperature difference.
The Earth’s thermal energy is enormous, yet only a part of it can be used. Geothermal Energy has only been employed in areas where geological conditions allow a carrier (water in liquid or vapour phases) to ‘carry’ heat from deep hot zones to the surface. This process produces geothermal resources. Other geothermal energy sources include hot springs, geysers, deep excavated wells (1-3 km), etc.
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Geothermal Energy Extraction Method
Wells 1.6 kilometres deep or deeper are drilled into underground reservoirs to produce geothermally generated electricity. These wells draw hot water and steam to power the turbines. Electricity generators are connected to the turbines in turn. In Larderello, Italy, geothermal electricity production began in 1904. Following are the methods to extract Geothermal heat.
Hydrothermal Heat Source
Water recharges into the earth through rain or surface bodies (such as rivers, lakes, or glaciers) and transfers heat to the surface where it is then heated by the hot rock beneath the surface brought about by seismic or volcanic activity. The Himalayas, the Alps, and Iceland all have hot springs, which proves this. For water to flow freely, both to replenish the system and to bring hot water to the surface, the area’s lithology must be porous.
Deep Geothermal System
Deep geothermal systems, include drilling a deep borehole to access hot basal rock and injecting water into the holes to generate steam. Using this method of resource extraction, a turbine is powered. Due to the high cost of accessing the deep base rock substrate, this method is rarely used.
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Geothermal Energy in India
Geothermal field research and exploration in India began in 1970. There are 350 areas in India where geothermal energy can be found, according to the GSI (Geological Survey of India). The Puga valley in Ladakh is home to the most promising of them. In India, there is a potential for geothermal energy of roughly 10 gigatonnes (GW) according to the Ministry of New and Renewable Energy, whose geothermal resources have been mapped (MNRE).
|Himalayas||J&K, Himachal Pradesh and Sikkim; PUGA hot spring in J&K and Manikaran in Himachal Pradesh.|
|Son-Narmada-Tapi (SONATA)||Madhya Pradesh, Chhattisgarh and Jharkhand; Tattapani spring in Chhattisgarh.|
|Cambay||Mainly Gujarat and some parts of Rajasthan|
|Mahanadi||Odisha, Taptapani Spring in Odisha.|
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Geothermal Energy Advantages
The benefits of using geothermal energy are listed below:
- Geothermal Energy emits only one-sixth as much CO2 as a natural gas plant, it is a cleaner fuel.
- Being unlimited and unending due to the constant flow of heat from the Earth, Geothermal energy is a renewable resource.
- Geothermal Energy is the only renewable energy source that is always available to humans, unaffected by day-night or seasonal fluctuations, and does not require storing.
- Geothermal Energy is essential to develop new energy sources, such as geothermal energy, given the need to replace power produced by coal with other energy sources.
- Geothermal energy can be used as a primary source of power as well as a replacement for electricity as a source of heat, depending on the geothermal characteristics and regional geographic conditions.
- Geothermal Energy is a site-specific renewable energy source that is great for supplying rural or interior populations’ energy demands.
- Geothermal heat pump systems use less room for equipment and consume 25% to 50% less electricity than conventional systems for heating or cooling.
- Hot spring mineral byproducts including silica, borax, and caesium may be employed.
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Geothermal Energy Disadvantages
The following list contains the drawbacks of using geothermal energy.
- Geothermal has been associated with other pollutants like sulphur dioxide and hydrogen sulphide despite producing minimal carbon dioxide.
- In the regions where they operate, geothermal generating facilities alter the topography and generate rifts and mild earthquakes. Building in a certain location is expensive upfront. It is sometimes referred to as “the most location-specific energy source known to man” due to its activity along the tectonic plates of the globe.
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Geothermal Energy Government Initiatives
- The government intends to offer a capital subsidy of up to 30% for industrial projects.
- Chhattisgarh’s first geothermal power plant is a collaboration between NTPC and the state’s renewable energy development agency (CREDA). Tattapani geothermal field in the province of SONATA.
- For research, design, development, and demonstration (RDD&D) for utilising geothermal energy in India, the Ministry of New and Renewable Energy (MNRE) offers significant incentives and subsidies.
- By 2022, the Ministry of Renewable Energy intends to produce up to 1000 MW of geothermal energy.
- According to the Geological Survey of India (GSI), India has been found to have a geothermal potential of 10,000 MW.
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Geothermal Energy UPSC
Due to the high cost of geothermal discovery, financial incentives may be introduced to promote the investigation of geothermal resources. Funding for exploration will motivate exploration organisations to undertake geothermal energy projects for electricity production and direct heat use. Additionally, it will draw private financiers for the expansion of geothermal energy. To entice private companies to develop geothermal energy in India, it may be urged to use foreign financing, knowledge transfer, and appropriate financial incentives.
India’s research has thus far mainly been surface-level, leaving a data gap for the design of power projects. Deciphering the properties of deep reservoirs is crucial for figuring out whether certain resources are viable for use in the production of electricity. Geothermal energy can help developing nations combat climate change while also raising living standards if there is strong international cooperation and backing from wealthy nations.