Waita, Japan geothermal development in harmony with onsen operations
Geothermal plants at Waita, Kumamoto, Japan (source: Baseload Power)
Alexander Richter
14 Aug 2022
The small-scale geothermal development at Waita in Kumamoto Prefecture, Japan is a great example on developing in geothermal in close harmony with local onsen operations.
A recent article by Japan’s national public broadcasting corp., NHK provides some interesting insights on current geothermal ambitions and efforts in Japan.
Deep in the mountains of Aso in Kumamoto Prefecture, there is a geothermal power generation company supported by an investment fund in which Bill Gates and Jeff Bezos also invest. NHK visited the hot spring resort “Waita Onsenkyo” in Oguni Town, Kumamoto Prefecture. It is a high-class ryokan with a wooden structure in one corner and a sense of history.
Mr. Kazuaki Kumagai, the president of the ryokan who welcomed us, is also the manager of a power generation company. At the site is also a small geothermal power plant with a height of about 5 meters.
This ryokan started geothermal power generation in February this year using the steam from the hot spring well.
Electricity generated for 200 households was supplied to an apartment building in Fukuoka City as clean energy.
Japan has a long history of geothermal power generation, but the development site is inevitably close to a hot spring area, and there is concern that the amount of water in the hot spring will decrease due to excavation and extraction of steam. The composition of hot spring associations confronting each other has occurred in various places.
However, even so, it is surprising that a hot spring inn will handle geothermal power generation by itself.
Mr. Kazuaki Kumagai, said that “actually, about 30 years ago, the town was divided into two groups, one in favour of the other and the other in opposition, and the plan of the business operator was set aside. Many residents are now concerned about the impact on the hot springs. It was so bad that even the local Bon dance could not be held. In the end, the plan was canceled. After that, a new power generation method that did not affect the hot springs was developed, and a system was created to work on geothermal power generation throughout the region. Now all the townspeople agree.”
Hot spring-friendly new technology
A new power generation method that does not affect hot springs is “binary power generation.” Conventional geothermal power generation requires very high temperature steam, and after power generation is completed, the cooled water is returned to the ground.
At that time, there was concern that the temperature of the underground source would drop.
Binary power generation uses a gas with a boiling point lower than that of water as an intermediary, making it possible to use the steam that has accumulated in hot spring areas as it is. It is a technology that does not directly affect the underground source.
With the advent of this technology, residents’ concerns are said to have been resolved.
In 2011, the Waita Hot Spring Village established a geothermal power generation company, Waitakai. The company is owned by all residents.
We introduced a system that digitally manages the amount and temperature of hot springs, and monitors the entire area to see if there is any impact on the hot springs.
The system has been opened to power generation companies other than Waitakai, and geothermal power generation is currently being carried out at seven locations in this hot spring area.
Mr. Kazuaki Kumagai, “We can effectively use the steam that was released into the atmosphere as it is. We can also earn income from power generation, and I hope that this area’s efforts will become a model.”
Source: NHK Japan
