Japan should tap the great potential of carbon-free geothermal resources

Japan, which has many volcanoes, is rich in geothermal resources. The public and private sectors should work together to strengthen their efforts to make the most of this energy source.

Environment Minister Shinjiro Koizumi has announced that the government will accelerate the development of geothermal power generation. By reviewing the operation of relevant laws and regulations, the government plans to shorten the period between surveys of suitable locations and the start of operations, which usually takes more than a decade, to as little as eight years.

As 80% of geothermal heat sources are concentrated in national and quasi-national parks, it has been pointed out that the criteria for allowing their development are unclear. Therefore, the government intends to present detailed requirements for the screenings.

The government has set a target of reducing Japan’s greenhouse gas emissions by 46% from the fiscal 2013 level by fiscal 2030.

To achieve this goal, it is essential to expand the use of renewable energy. Solar and wind power generation will play a central role. However, geothermal power generation also has great potential. It is only natural to seek ways to utilize geothermal power.

Geothermal power generation taps into magma-heated water and steam from a layer about 2,000 meters underground to rotate turbines that generate electricity. Unlike solar and wind power, this system can generate electricity at a stable output regardless of weather conditions. It also does not emit greenhouse gases.

Japan has an estimated 23,470 megawatts of geothermal resources, the third largest in the world after the United States and Indonesia. However, Japan’s current generation capacity of 600 megawatts is less than that of one nuclear reactor, standing at 10th in the world.

In fiscal 2019, geothermal power generation accounted for 0.3% of the nation’s total electricity supply, a figure that has not increased over the past 10 years. The government needs to closely examine the cause and expedite improvement measures.

It costs about ¥500 million to drill a well for geothermal power generation. However, since it is difficult to know in advance whether such a well will actually produce hot water, the success rate of such geothermal power generation projects is said to be about 30%. Technological innovation is needed to improve development accuracy and reduce related costs.

Technology has already been put into practical use to measure underground magnetism from helicopters and determine the locations of hot water. Efforts should be made to use such technology to improve the success rate of drilling for geothermal power generation. It is also important to reduce the drilling costs by measures such as downsizing equipment.

It is also vital to gain the understanding of local people. Those in the hot spring businesses, such as hotels and Japanese-style ryokan inns, often oppose the development of geothermal power generation because they are concerned about a potential decrease in the amount of hot water and changes in the water quality.

The Wasabizawa geothermal power plant in Yuzawa, Akita Prefecture, which started operating in 2019 as the nation’s first such large-scale power plant in 23 years, will serve as a useful reference. The operating company reached an agreement with the local people on such matters as the company monitoring the amount of hot water and sharing the data with them.

The hot water used for geothermal power generation is also utilized to grow vegetables in greenhouses in an effort to vitalize the local community. It is hoped that such efforts will be expanded to other regions.

— The original Japanese article appeared in The Yomiuri Shimbun on May 21, 2021.