Japan has high hopes for geothermal power in Kyushu

The Yomiuri Shimbun
Yukio Goto, leader of Waitakai LLC, speaks to The Yomiuri Shimbun in Oguni, Kumamoto Prefecture, in October.

FUKUOKA — As expectations grow for the expansion of geothermal power generation as a renewable energy source to help realize a decarbonized society, development may be accelerated in Kyushu, which is blessed with hot spring resources.

Several pillars of steam were seen rising at the hot spring resort Waita Onsen Village in Oguni, Kumamoto Prefecture, located at the foot of Mt. Waita. A little farther up in the mountains, there is a geothermal power plant, from which white steam spews out with much greater vigor.

A group of 30 local residents established Waitakai LLC and began operating a geothermal power plant with a maximum output of 1.995 megawatts in 2015. The plant annually generates more electricity than is consumed by all the households in the town of Oguni. The residents’ company sells the electricity generated to a power company.

Courtesy of Kyushu Electric Power Co.
>Hachobaru Geothermal Plant, one of the largest such power plants in Japan, is seen on a plateau surrounded by mountains in Kokonoe, Oita Prefecture.

All the business aspects, from construction to daily operation of the plant, have been outsourced to another company, a subsidiary of Chuo Electric Power Co., a Tokyo-based power producer and supplier. This commissioned company also contributed ¥1.5 billion to the geothermal energy project.

Waitakai receives ¥120 million annually as the owner of the land and the wells from which high-temperature water and steam are extracted from the ground. This revenue from electricity sales minus commission fees is used to help the community by building tourist facilities and purchasing microbuses that are donated to the local high school.

A second power plant, with a maximum output of 5 megawatts, is in the planning stages, and the drilling of wells has already been completed.

“The steam in this area has the potential to generate more power,” said Yukio Goto, the 53-year-old leader of Waitakai. “We will use the local resources to create employment and industry in our hometown so that our grandchildren will come back [to live and work here].”

No. 3 in the world

According to the Natural Resources and Energy Agency, the volcanic nation of Japan has the third-most potential geothermal resources in the world, following the United States and Indonesia. The potential is estimated at 23,000 megawatts.

There were 70 geothermal power plants in Japan as of the end of March 2020, about 70% of which were in Kyushu, according to the Thermal and Nuclear Power Engineering Society.

There is a growing movement to use Kyushu’s geothermal potential as a renewable energy source. Kyushu Electric Power Co. is an operator of the Hachobaru Geothermal Plant in Kokonoe, Oita Prefecture, which is one of the largest geothermal plants in Japan with a maximum output of 110 megawatts. As a leader in geothermal power generation, the company has made it clear that it is actively seeking more potential, already launching resource searches in Oita, Kumamoto and Kagoshima prefectures.

Renova Inc., a Tokyo-based renewable energy developer, focused on the site of a hotel that closed 20 years ago in Minami-Aso, Kumamoto Prefecture. In cooperation with other companies, it began construction of a geothermal power plant in July. Renova plans to start operations at the plant in December 2022 as a “symbol of reconstruction” from the 2016 Kumamoto Earthquake.

“We would like to consider offering tours to make the plant a tourist destination,” an official of the company said.

Only 0.3% of energy mix

Geothermal plants use steam or hot water heated by underground magma to get turbines moving. Typically, the steam is extracted from geothermal reservoirs 1 to 3 kilometers underground.

The first such facility in Japan is the Matsukawa Geothermal Power Station in Hachimantai, Iwate Prefecture, which began operating in 1966. Its maximum output is now 23.5 megawatts.

Nearly 55 years later, the Basic Energy Plan approved by the government in October included a target to double the number of geothermal power generation facilities by 2030.

In general, geothermal development is hampered by the difficulty of finding heat sources. It takes at least 10 years to commercialize and requires huge costs for development. But the daily operating cost for power generation is low and geothermal power is more stable than solar or wind power as it is not affected by weather.

The government has positioned geothermal power as a baseload power source in its new Basic Energy Plan. However, geothermal power only accounts for 0.3% of Japan’s energy mix. With the plan’s goal of doubling the number of facilities, the aim is to raise the percentage to 1% by 2030.

The Environment Ministry is also pushing for the promotion of geothermal power generation. In September, the ministry effectively shifted its policy to allow development in national and quasi-national parks where 80% of the nation’s geothermal resources are concentrated, such as Aso-Kuju and Kirishima-Kinkowan, both in Kyushu.

Consent of residents needed

The biggest challenge is obtaining the consent of residents, especially those near hot spring resorts. There are strong concerns that the hot springs will run out or decrease in quantity. In Ibusuki, Kagoshima Prefecture, the municipality stopped the construction plan in 2016 due to opposition from hot spring hotels.

The plan in Oguni was also once halted because the large-scale development plan caused a split among the residents. So monitoring of the amount of hot spring water was begun by a council consisting of the Oguni town government and the five companies promoting the project in the town.

The companies will make a contribution based on the amount of electricity generated, which will be used for resource management. This is a rare initiative in Japan.

“There will be more geothermal development in the future,” said Ryuichi Itoi, a professor emeritus at Kyushu University, a specialist of geothermal reservoir engineering. “Local governments must play a role in coordinating between developers and residents.”