Geothermal Energy

• Geothermal energy is natural heat from the interior of the earth that can be used to generate electricity and heat buildings.
• The earth’s crust has a layer of hot and molten rock, called magma, which continually produces heat.
• The amount of heat within 10,000 meters of the earth’s surface contains 50,000 times more energy than all the oil and natural gas resources in the world.
• Geothermal resources fall into three categories: geopressurized zones, hot-rock zones, and hydrothermal convection zones.
• Only geopressurized zones are currently being exploited on a commercial basis.
• Natural examples of geothermal energy include geysers, lava fountains, and hot springs.

Advantages:

• Renewable
• Easy to exploit in some cases
• CO2 production less than with fossil fuel
• High net energy yield

Disadvantages:

• Not available everywhere
• H2S pollution
• Geothermal energy harnessing produces some water pollution

How is it captured?

• Geothermal systems are found in regions with normal or slightly above normal geothermal gradient.
• Geothermal systems are commonly found around plate margins with significantly higher geothermal gradients.
• The most common way of capturing geothermal energy is by tapping into naturally occurring hydrothermal convection systems.
• Heated water is forced to the surface, making it easy to capture steam and use it to drive electric generators.
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Challenges

• Geothermal energy is limited to areas above suitable pockets of water and steam.
• Many of these areas are tectonically active, which makes it challenging to install large-scale power plants.
• Setting up infrastructure for geothermal energy is expensive, including drilling wells and staffing power plants.
• Geothermal energy is expensive to tap into, with upfront costs ranging from $2-$7 million for a plant with a 1 MW capacity.
• Geothermal energy is not unlimited, and wells can only extract a certain amount of water and steam before the source dwindles.
• Geothermal energy is location specific and can only be exploited in areas where the energy is accessible.
• Geothermal power plants must be located near specific areas near a reservoir, as it is not practical to transport steam or hot water over distances greater than two miles.
• Geothermal energy may release greenhouse gases stored under the Earth’s surface, although these emissions are far lower than those associated with fossil fuels.
• Geothermal energy may trigger earthquakes due to alterations in the Earth’s structure as a result of digging.
• Geothermal energy needs to be properly managed to maintain its sustainability.
• The plant must be able to contain any leaked radioactive gases and ensure safe disposal.

Geothermal Energy in India

• Geothermal exploration and study began in India in 1970.
• The Geological Survey of India has found 350 geothermal energy locations, with the most promising being in the Puga valley of Ladakh.
• India has seven geothermal provinces and numerous geothermal springs.
• The geothermal potential of India has been mapped by GSI, and the Ministry of New and Renewable Energy estimates a potential of 10 GW of geothermal power.
• In 2013, the Chhattisgarh government decided to establish a geothermal power plant in Tattapani in the Balrampur district.
• In 2021, an agreement was signed to establish the first geothermal power project in Ladakh.
• Satellites like the IRS-1 have helped locate geothermal areas through infrared photographs.
• The Indian government provides a capital subsidy of up to 30% for industrial geothermal projects.
• The first geothermal power plant in Chhattisgarh will be established through a joint effort of NTPC and CREDA in the Tattapani geothermal field.
• The Ministry of New and Renewable Energy provides incentives and subsidies for Research, Design, Development, and Demonstration (RDD&D) to harness geothermal energy in India.
• The Ministry of Renewable Energy aims to generate up to 1000 MW of geothermal energy by 2022.

Major sites for geothermal energy in India

• Puga geothermal field
• Chhumathang geothermal field
• Manikaran geothermal field
• Beas valley
• Satluj and spiti valley
• Tapoban geothermal field, Chamoli, Uttarakhand and Alaknanda Valley
• Tatapani geothermal field
• Salbardi region
• Anhoni- Samoni area
• Unkeshwar
• Godavari Graben
• Andaman-Nicobar region
• Damodar Valley basins
• Western thermal province
• Cambay geothermal region
• Konkan geothermal provinces
• Sohna thermal region
• Tuwa and Chhabsar geothermal fields, Gujarat
• Lasundra geothermal province