What is geothermal power generation?
Geothermal power generation is a type of renewable energy
Geothermal power generation is one type of renewable energy. Power is generated by turning a turbine using the power of high-temperature water or steam heated by underground magma. Compared to power generation methods using solar and wind power, which are also renewable energies, it is possible to obtain a stable amount of power generation regardless of the weather.
Geothermal power generation mechanism
A geothermal power plant consists of production wells that extract steam and hot water from underground, above-ground equipment such as separators, turbines, and generators, and injection wells that return the hot water underground. Heat can be extracted semi-permanently by circulating water through the wells and the geothermal reservoir *.
Japan is a volcanic nation, and it is believed that there is a great deal of untapped geothermal Resources derived from underground magma, and further development is anticipated in the future.
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Geothermal reservoir: A layer containing high-temperature groundwater heated by underground magma, etc.
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Rain that falls on the ground permeates into the ground and remains in some strata, becoming groundwater.
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Production wells are dug in areas where groundwater is at high temperatures due to magma reservoirs, etc., and steam and hot water are pumped up from underground.
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Steam and hot water pumped up from underground are separated using a device called a separator.
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The steam sent from the separator rotates a turbine and generates electricity. The hot water is returned underground.
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The steam used in the turbine is cooled with cooling water in a condenser and condensed into water.
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The water produced in the condenser is further cooled. The cooled water is recycled in a condenser. From the cooling tower, the warm water vapor that removes heat from the water is cooled by contact with the outside air and comes out as steam.
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Returning underground is done at a suitable distance from production wells. The water returned to the ground is heated underground before being pumped out of the ground again.
Japan: A country with great geothermal Resources
The United States ranks first in the world in geothermal Resources, with 30 million kW equivalent. Japan ranks third in the world after Indonesia, boasting 23.47 million kW of geothermal Resources. However, Japan's current power generation capacity is only 530,000 kW, which is about 0.3% of electricity demand. There are issues with expanding geothermal power generation, such as long lead times, exploration risks, and the connection and costs of transmission lines. However, since the Great East Japan Earthquake, there has been a desire to promote geothermal power generation more actively, and the government is currently reviewing and considering systems such as deregulation and shortening and one-stop license procedures.