Spread over a hillside high above this city lies Ogura, a quiet neighborhood of single-family homes and traditional inns. White plumes of steam billow from dozens of metal chimneys that sprout from rooftops across the neighborhood, fed by the hot springs that lie underground and pipe scalding spring water into baths known in Japan as onsens.
When Kazunori Ueda sees this steam, he doesn’t think of a two-hour soak in a tub (not that he minds taking one). He sees untapped geothermal energy that can help power Japan, an industrial nation that relies on imported fossil fuels to keep the lights on, all the more so since the 2011 Fukushima nuclear-reactor meltdown.
Mr. Ueda is the managing director of Sanko Electric, a company founded by his father in 1975. In 2016, Sanko Electric installed its first power generator over an onsen in Ogura and is building another one in the nearby neighborhood of Horita. The generators are small, about 70 to 110 kilowatts each, but represent a modest geothermal boom in Japan, with support from a government mindful of the backlash against nuclear power.
Thanks to a nearby volcano, Beppu, a city of 120,000 people on the southwestern island of Kyushu, sits atop a geothermal gold mine: 2,217 wellheads that discharge a greater volume of hot water than any place in the world except Yellowstone National Park. “It would be a shame to let them go to waste,” Ueda says.
But not everyone in Japan is on board. For decades, many onsen hotel and bathhouse owners have opposed the development of geothermal energy for fear that it would divert water from their baths and spill effluent into the underground hot springs, spoiling a beloved form of relaxation that Japanese have indulged in for hundreds of years.
With dozens of geothermal plants scheduled to open in Beppu, Goto Mitsuteru, the manager of a local hotel where rooms can cost $190 a night, is anxious to see if they have any effect on the onsen where his guests go to soak. So far, the answer is negative, but he still seems on edge about the geothermal boosters making a play for his town’s aquifers.
“I haven’t noticed any changes in the water since we opened 12 years ago,” admits Mr. Mitsuteru. “I just don’t know how long that will last.”
'A lot of unknowns'
In many ways, the rise of geothermal energy in Japan is long overdue. The country has the world’s third-largest geothermal reserves, behind the United States and Indonesia. The International Energy Agency estimates that Japan only uses about 2 percent of its geothermal capacity, which, at 23 gigawatts, is the equivalent of 23 nuclear reactors.
“There are a lot of unknowns,” says Ali Kharrazi, an assistant professor at the University of Tokyo who has researched geothermal energy in Japan. “We’re still waiting for better technology and better modeling that can tell us what is happening to these underground springs.”
Here in Beppu, scientists successfully demonstrated for the first time in 1925 how onsens could be harnessed to generate electricity. Yet today only 0.3 percent of Japan’s electricity comes from geothermal plants; natural gas, coal, oil, and hydropower supply the rest.
Before the Fukushima disaster, Japan’s 54 nuclear reactors had generated 29 percent of the country’s electricity. All 54 were shut down and only three have been allowed to restart. To help fill the gap, Japan has begun to tap geothermal energy with a flurry of projects from the northernmost island of Hokkaido to Kyushu in the south.
The country’s first new geothermal plant in 15 years opened four years ago in Kumamoto Prefecture. Next year, a 42-megawatt plant, the largest built in Japan in 23 years, is scheduled to start operations in Akita Prefecture. And in Beppu, dozens of small-scale projects, like Sanko Electric’s generators, are getting underway.
Japan wants to triple its geothermal output by 2030. To reach that goal, the government has lifted a decades-old ban on building geothermal plants in national parks, which contain close to 80 percent of its reserves. It also plans to conduct more geothermal surveys this year.
Yoichiro Kono, director of the Fuel Policy Planning Officeat the Agency for Natural Resources and Energy in Tokyo, says while this progress is encouraging, geothermal represents a small part of Japan’s overall energy consumption.
“The public is generally in favor of geothermal energy,” Mr. Kono says. “The biggest opposition comes from onsen areas. We must do everything we can to protect them.”
A win-win for innkeepers
Some of the small-scale projects in Beppu may provide an answer to this problem.
Sanko Electric’s generators rely on onsen water, which is relatively low in temperature (about 250 to 300 degrees Fahrenheit) compared with traditional generators that need water at 575 degrees or hotter. That means they’re less invasive because they don’t need to pull water from springs deep underground. Instead, they can siphon off water from springs that lie just beneath the ground all over the city. Sanko Electric’s generator sits on a plot of land about the size of a semi-trailer behind a black metal fence on a residential street.
Mini-generators that run on 300-degrees-or-less water could even prove to be a boon for the innkeepers that currently stand in the way of geothermal energy.
In a report published in December, Frost and Sullivan, a US market-research company, estimated that thousands of hot springs could produce as much as 7.5 gigawatts of electricity. As the technology improves and prices drop, the report says, hotels and bathhouses could install their own geothermal generators to produce electricity before transferring the water into their spas, effectively a double dip on the same natural resource.
Since 2012, operators of small electricity plants can sell power to Japan’s grid at a preferential rate, compared with larger facilities, while plants rated at less than 7.5 megawatts don’t require the same environmental assessment that often delays larger projects for more than a decade.
Hori Hideki, director of Beppu’s Environmental Planning Office, says the city has approved the construction of 30 small-scale geothermal plants that will begin operating this year. “So far we haven’t turned down any new projects,” he says. When asked whether they pose a threat to the onsens that local hotels and bathhouses rely on, he says it’s too early to know and that the city is closely monitoring the water and temperature levels of hot springs.
Kenji Tsukazaki, an engineer at a geothermal plant at the Suginoi Hotel, an upscale resort in Beppu, tells a different story. When he started work at the plant 30 years ago, the average temperature of the water was 300 degrees Fahrenheit. It has since dropped to 250 degrees. If it drops any lower, it won’t be hot enough for the plant to operate. Mr. Tsukazaki predicts that will happen in the next 10 years as more plants are built. He admits that he doesn’t exactly know why the temperature keeps dropping, but he has a theory.
“There are too many wells,” he says. “Too many people have tapped into the onsens.”