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Mitsui Fudosan and two other companies start closed-loop geothermal power demonstration in Ibusuki

Three companies including Mitsui Fudosan have begun a joint demonstration of closed-loop geothermal power generation in Ibusuki, Kagoshima Prefecture, which is described as the first of its kind in Japan.

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Mitsui Fudosan and two other companies start closed-loop geothermal power demonstration in Ibusuki
写真はイメージ / 写真: W. Bulach / CC BY-SA 4.0 / Wikimedia Commons ライセンス

Mitsui Fudosan and two other companies have started a joint demonstration of closed-loop geothermal power generation in Ibusuki, Kagoshima Prefecture. The project is described as the first of its kind in Japan and is drawing attention as a move to test a new geothermal method within the country.

Geothermal power generation extracts high-temperature heat from underground and uses the resulting steam to turn turbines to produce electricity. Japan, a volcanic nation, is said to have abundant geothermal resources. Unlike solar and wind power, geothermal power is not affected by weather or time of day and can supply electricity relatively steadily day and night. It is expected to serve as baseload power, which helps keep output stable.

Conventional geothermal power plants pump underground hot water and steam directly from wells for use. Because this method draws on underground hot water, there are concerns about its effects on nearby hot springs and groundwater, and gaining local understanding has become a key challenge for development.

In a closed-loop system, underground hot water is not extracted directly. Instead, a working fluid circulates through sealed pipes to recover heat. The heat medium absorbs heat underground, releases it at the surface, and then returns underground, so underground hot water and steam are not taken out. The method is expected to ease concerns such as the impact on hot springs.

Ibusuki is known as a hot spring resort. Balancing the use of geothermal resources with protecting the environment of a tourist area has long been a challenge for the community. The start of a demonstration of a new method there is significant for considering how geothermal development and local resources can coexist.

The demonstration is being jointly conducted by Mitsui Fudosan and two other companies. Going forward, the project will enter a stage in which the stability of power generation and the practicality of operations will be assessed. From the standpoint of decarbonization, geothermal power, a renewable energy source that emits no CO2 when generating electricity, needs to be expanded. The results of testing the new method will serve as material for deciding on its wider use.

Geothermal development requires time and money for surveys and drilling, so demonstrations at the early stage are important for establishing the technology. Attention is focused on whether the work in Ibusuki will serve as an example of how future geothermal projects should proceed.

BLUE NOVA Hydrogen Journal view

Geothermal power is a renewable energy source that can generate electricity steadily day and night, regardless of weather. Conventional methods use underground hot water and steam, which has raised concerns such as effects on hot springs. Closed-loop systems use a working fluid in a sealed circuit underground, which is seen as a way to ease those concerns. Because the demonstration in Ibusuki is described as the first of its kind in Japan, it is a test case for expanding geothermal power in the country. Results there will also serve as a reference point for how geothermal regions and hot spring resorts can coexist.

Source: Sustainable Japan
This article was written by the editors based on the cited report and translated from Japanese. AI is used to assist in writing and translation.

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