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 return wells that return hot water underground. By circulating water through wells and geothermal reservoirs *, heat can be extracted semi-permanently.
Japan, a volcanic country, is said to have many untapped geothermal Resources derived from underground magma, and further development is expected 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 rich in geothermal Resources
The United States ranks first in the world in terms of geothermal Resources, equivalent to 30 million kW. Japan boasts 23.47 million kW of geothermal Resources, which ranks third in the world after Indonesia. However, the current power generation capacity in Japan is only 530,000 kW, which accounts for approximately 0.3% of electricity demand. Expanding its introduction poses challenges such as long lead times, exploration risks, and transmission line connections and costs. However, since the Great East Japan Earthquake, there has been a desire for more active promotion of geothermal power generation, and the government is implementing and considering system reforms such as deregulation, shortening the permitting process, and making it one-stop.