By Hiroko Tabuchi
A treasured getaway for travelers in Japan is a retreat to one of thousands of hot spring resorts nestled in the mountains or perched on scenic coasts, some of which have been frequented for centuries.
All are powered by Japan’s abundant geothermal energy. In fact, Japan sits on so much geothermal energy potential, if harnessed to generate electricity, it could play a major role in replacing the nation’s coal, gas or nuclear plants.
For decades, however, Japan’s geothermal energy ambitions have been blocked by its surprisingly powerful hot spring owners.
“Rampant geothermal development is a threat to our culture,” said Yoshiyasu Sato, proprietor of Daimaru Asunaroso, a secluded inn set next to a hot spring in the mountains of Fukushima prefecture that is said to date back some 1,300 years. “If something were to happen to our onsens,” he said, using the Japanese word for hot springs, “who will pay?”
Japan, an archipelago thought to sit atop the third-largest geothermal resources of any country on Earth, harnesses puzzlingly little of its geothermal wealth. It generates about 0.3% of its electricity from geothermal energy — a squandered opportunity, analysts say, for a resource-poor country that is in desperate need of new and cleaner ways of generating power.
One answer to that puzzle lies in Japan’s venerable hot springs like the one at the inn run by Sato. For decades, inns like his have resisted geothermal projects out of fears that they will damage their mineral-rich hot springs.
In a preemptive move, Sato has fit Asunaroso with monitoring equipment that tracks water flows and temperatures in real time, and is pushing for onsens across the country to do the same. He has led the opposition to geothermal development as the chair of an organization that translates loosely as the Society to Protect Japan’s Secluded Hot Springs.
Bureaucrats in Tokyo, Japan’s giant electrical utilities and even the nation’s manufacturing giants have been no match. “We can’t forcibly push a project forward without the proper understanding,” said Shuji Ajima of the Tokyo-based Electric Power Development Co., also called J-Power, which operates just one geothermal plant in Japan, accounting for 0.1% of its power generation. The utility has been forced to give up on a number of geothermal projects in past decades.
“Geothermal plants are never going to be game-changers, but I believe they can still play a role in carbon-free energy,” he said.
‘It’s all the things Japan needs’
Hot springs are a small miracle of nature, fed by rainwater that seeps into the rock that is heated by the Earth’s interior before bubbling up to the surface, a process that takes years, even decades.
More than 13,000 onsen inns and baths dot the country. There are strict rules, displayed in numerous languages on posters plastered on onsen walls. No bathing suits. No soapy bodies allowed. And an additional COVID-era requirement, “mokuyoku,” or silent bathing — no chatter in the baths.
Geothermal power plants, on the other hand, draw on wells drilled deeper in the Earth’s crust, pumping up steam and hot water to power giant turbines that generate electricity. Developers say that because plants draw from sources deep beneath onsen springs, there is little possibility one will affect the other.
Still, the interconnection between hot springs and deeper geothermal heat remains something of a mystery. When hot spring flows change, it’s often difficult to pin down a cause.
We don’t yet fully understand the full consequences of geothermal development, said Yuki Yusa, a professor emeritus and expert in geothermal sciences at Kyoto University.
Japan, the world’s fifth-largest emitter of planet-warming gases, needs more clean energy to meet its climate goals and to rein in its dependence on fossil fuel imports. Much of its nuclear power program remains shuttered after the 2011 Fukushima nuclear disaster. Geothermal power’s green credentials, combined with its relatively low cost and its ability to produce electricity consistently round the clock, have made it a promising source of renewable energy.
The Japanese government, which seeks to triple the country’s geothermal capacity by 2030, has tried to smooth the way for more projects by opening up geothermal development in national parks and speeding up environmental assessments.
If Japan were to develop all of its conventional geothermal resources for electricity production, it could provide about 10% of Japan’s electricity, according to the Institute for Sustainable Energy Policies in Tokyo. That would be more electricity than Japan generated from hydropower, solar, wind or nuclear in 2019.
“It’s domestic. It’s renewable,” said Jacques Hymans, an energy expert at the University of Southern California. “It’s all the things Japan needs.”
But across Japan, local governments have recently introduced a fresh round of restrictions. Kusatsu, an onsen resort town north of Tokyo, passed an ordinance last year that would place the onus on developers seeking the town’s approval to prove that a geothermal project wouldn’t affect local hot springs, a difficult hurdle. Oita, a prefecture that has more onsen springs than any other in Japan, recently expanded a no-drill zone in the city of Beppu, considered Japan’s onsen capital.
“We understand the nation’s energy needs,” said Yutaka Seki, an executive director at the National Hot Spring Association, which represents inns nationwide. “We aren’t opposed to geothermal energy for the sake of opposing it,” he said. “But we strongly caution against unchecked large-scale development.”
Signs of change
Yuzawa, in the snowy northern province of Akita, is a rare example of a hot spring town that has embraced geothermal energy.
An early developer, Dowa Mining, involved local community leaders in its planning, hiring the city’s best graduates, sending officials to local festivals and even offering to drill springs for local onsens. The local government, for its part, was eager to foster a new industry in a remote region of Japan. A local milk farmer now uses the hot spring water to pasteurize his milk and yogurt.
Japan had hoped for more Yuzawas. The nation opened its first commercial, large-scale geothermal power plants in 1966, and in the following decades, operators added about a dozen more, including one in Yuzawa. But with rising local opposition from hot spring inns, Japan has added almost no geothermal capacity since the 1990s.
That’s even as Japanese manufacturing giants, like Toshiba, have come to dominate the global market for geothermal turbines. Very little of their business is on their home turf.
So in 2019, when Japan’s first large geothermal plant in 23 years opened in Yuzawa, with the ability to power almost 100,000 homes, it was a breakthrough.
The toughest challenge facing any geothermal project in Japan isn’t related to the geology or technology, said Shun Iwata, a retired Dowa Mining executive who embedded in Yuzawa for nearly two decades to bring locals round on the idea. He is now an adviser to the city. “What’s more important is working on the community and building relationships,” he said.
Even in Yuzawa, though, there has been controversy. Since late 2020, a local inn has had to periodically close after its spring dwindled.
Yuzawa city maintains the city’s geothermal development wasn’t the cause.
“I can’t say I’m not concerned,” said Masami Shibata of Abe Ryokan, one of Yuzawa’s hot spring inns. Still, geothermal energy has become a part of Yuzawa city’s fabric, she said. “I think it’s possible for both hot springs and geothermal to coexist.”