An overview on Japan’s geothermal energy potential
How Japan can meet its future energy needs is not necessarily something you think about while enjoying a nice long soak in a hot-spring bath.
But the hot water you’re soaking in is part of the solution, say advocates of geothermal power.
Renewable energy sources such as geothermal have been getting more attention since the 2011 Fukushima disaster exposed the risk — or folly — of nuclear power.
One expert says geothermal power could supply 10 percent of the country’s energy needs by 2050.
That looks like a pipe dream compared to the current situation. Geothermal plants currently produce just 0.2 percent of Japan’s electricity.
The Japan Oil, Gas and Metals National Corp. estimates the country’s geothermal potential at 23,400 megawatts, putting it at No. 3 in the world behind the United States and Indonesia.
However, Japan has an installed geothermal capacity of only some 500 megawatts, placing it in 10th spot worldwide.
Even a much smaller country such as Iceland — which, like Japan, has lots of seismic activity — has a geothermal capacity of 665 megawatts.
So why doesn’t Japan make better use of this theoretically abundant energy resource?
Well, it’s complicated.
Long before the Fukushima catastrophe, some people realized that Japan’s geothermal resources could play a bigger role in helping the country meet its energy needs.
In his 1985 novel, “Kirikirijin” (“The People of Kirikiri”), Hisashi Inoue imagines an independent Tohoku that relies on geothermal energy.
As one of the characters in the book — a local policeman — explains to a visitor to the new republic: “Electricity is free here thanks to this national geothermal power plant. Hot water heated by underground hot springs is also supplied to each household through pipes. So hot water is also free.”
The visitor asks why the rest of Japan doesn’t take advantage of the abundant energy lying underground.
“It’s simply because leaders of our country have more brains than the leaders of Japan,” is the policeman’s caustic reply.
The policeman might have also mentioned environmental concerns — including the possibility of a negative impact on hot-spring resorts — and the high cost of exploratory drilling and building geothermal plants.
Over the years, Japan has made tentative moves to exploit its geothermal resources.
The country’s first geothermal power plant was an experimental one that began operating near the hot-spring resort city of Beppu, Oita Prefecture, in 1925. However, it wasn’t until 1966 that the first full-scale plant was constructed in Japan. Built by Japan Metal & Chemicals Co., Ltd. in Matsukawa, Iwate Prefecture, it has an annual output capacity of 23.5 megawatts.
More geothermal plants were developed and went online in the years that followed. At the time of the Fukushima nuclear accident, there were 17 plants in Japan — primarily in Tohoku and Kyushu — with a total generating capacity of approximately 500 megawatts. Twenty-three small-scale plants have gone online since then, mainly due to the introduction of the feed-in tariff system.
Geothermal power plants operate on the same principle as nuclear plants: Steam turns turbines that produce electricity. The difference is that with geothermal, the steam comes from water that has been heated by subterranean seismic activity, instead of water that’s heated through atomic fission.
“The strong points of geothermal power plants are the same as nuclear power plants,” says Kasumi Yasukawa, deputy director of the Renewable Energy Research Center at the National Institute of Advanced Industrial Science and Technology.
Yasukawa says that both are stable, high-capacity energy sources that are not affected by the weather. They have low carbon dioxide emissions and they have a high energy return — in other words, the ratio between the energy they use and the energy they produce.
The difference, of course, is that geothermal plants don’t pose threats to the environment such as meltdowns or radioactive waste disposal. They can also be operated 24 hours a day, seven days a week.
The government has set a target of renewable energy sources supplying between 22 and 24 percent of electricity by 2030, with geothermal providing 1.6 gigawatts, or 1 percent of Japan’s power.
“We support a more aggressive target of around 40 percent for renewables,” says Tatsuya Wakeyama, a senior research fellow at the Tokyo-based Renewable Energy Institute. “We think the target for geothermal is too low.”
Wakeyama says most researchers believe 2.6 gigawatts is a realistic goal for 2030.
Harnessing the energy from all the hot water produced by the archipelago’s abundant seismic activity sounds like a no-brainer. However, advocates of renewable energy who want Japan to make better use of the resource face a powerful opponent: hot-spring resort operators.
Yutaka Seki, executive managing director of the Japan Spa Association, says onsen operators believe geothermal development has a negative impact on hot springs.
“However, we can’t prove it scientifically,” Seki says. “We can guess geothermal development will have a certain influence on hot springs, but we cannot scientifically prove that geothermal development will certainly cause hot springs to dry up and or change the quality of hot springs. The onsen industry hasn’t collected such data at all.”
Seki says the association’s 1,300 members make daily checks of the quality and temperature of the water they use.
“We’ve heard that geothermal development could affect hot springs in 10, 20 or 30 years, so we may be able to gather data by then,” he says.
Seki points to the hot springs at Ebino Kogen in Kyushu. They’ve dried up.
“Operators of the spa facilities argued that geothermal development was to blame,” he says. “However, the central and local governments insisted geothermal development had nothing to do with the drying up of the hot springs.”
Seki says the Yanaizu-Nishiyama geothermal power plant in Fukushima Prefecture has affected the quality of local hot springs and reduced the amount of hot-spring water.
“Developers can’t say with full confidence that geothermal development does not affect nearby hot springs at all,” he says.
Onsen operators need capital — and time — to conduct surveys in order to find the subterranean hot water they need. The same goes for geothermal power developers.
“It takes a lot of time to carry out a geothermal resource survey,” Wakeyama says.
It also takes a lot of money. Drilling costs mean it’s about three times as expensive to build a geothermal power plant as it is to build a coal-fired plant.
In the 1970s, concerns over their possible impact on the landscape led to revision of relevant legislation to avoid development of new geothermal plants.
“Most of Japan’s geothermal resources are in volcanic areas, and most of those (80 percent is the figure he cites) are in natural parks,” Wakeyama says.
“From my point of view, a landscape with a geothermal plant is acceptable if the building isn’t too tall,” Wakeyama says. However, he admits that pipelines and steam rising from the ground can be a blot on the landscape.
He points to the example of Japan’s biggest geothermal plant, Hatchobaru, in Oita Prefecture. It has a generating capacity of 110 megawatts.
“It’s in a national park,” Wakeyama says. “It’s a sightseeing spot. I think most visitors accept the power plant.”
Katsuki Ishimaki, deputy director of the Natural Resources and Fuel Department at the Ministry of Economy, Trade and Industry’s Agency for Natural Resources and Energy, believes geothermal plants can co-exist and co-prosper with national parks and hot-spring resorts.
“The operators of the plants are required to provide relevant information to the local authorities and local residents,” Ishimaki says. “In particular, they must respond to concerns of hot-spring managers with the data obtained through the monitoring process of the hot-spring wells. We encourage the operators to make an effort to deepen mutual understanding with local residents.”
Seki says onsen operators are willing to sit down with geothermal power developers to find ways of working together.
“We’ve talked with them before, but we then both became radical, and communication became difficult as a result,” Seki says. “But this year we are going to set up a committee with the development side to hold talks again to find common ground.”
One is tempted to suggest that the two sides try to work out their differences in the convivial atmosphere of a hot-spring bath.
Ishimaki says that the hot water used by geothermal plants can be utilized by local hotels and greenhouses, for example, after power generation in what he terms “multi-stage usage.”
Political support for geothermal development in Japan transcends party lines. The Bipartisan Parliamentary Committee for Geothermal Energy Promotion is working to promote the resource in various ways. In 2012, for example, the committee signed a memorandum of understanding with Iceland to share geothermal knowhow.
“We need deregulation and public understanding to develop Japan’s geothermal resources,” says Teruhiko Mashiko, co-president of the committee and a Democratic Party for the People lawmaker from Fukushima Prefecture in the Upper House.
The regulatory framework for geothermal power has in fact been changing. In 2015, legislation was revised to permit drilling for geothermal resources in some sections of national parks.
Ishimaki says the government is committed to making full use of the country’s geothermal energy potential. Its guiding principle is “3E+S” — achieving energy security, economic efficiency and environmental protection without compromising safety.
“We announced the ‘Long-term Energy Supply and Demand Outlook’ in July 2015 on the basis of that viewpoint,” Ishimaki says. “It indicates that there is no single energy source capable of achieving 3E+S by itself. We set the target to introduce geothermal energy to 1.0-1.1 percent of the power supply by fiscal 2030.”
Ishimaki says that figure isn’t etched in stone.
“We do not intend to limit the geothermal energy target to 15 gigawatts in the future,” he says. “The target for 2030 is simply one objective to aim for and, in the future, we will make full use of Japan’s potential to maximize the introduction of geothermal energy.”
Hurdles that developers face include the high cost of finding and developing geothermal resources. The Ministry of Economy, Trade and Industry’s Energy Agency provides subsidies of up to 50 percent of the cost of drilling exploratory wells, low-interest loans and insurance for “development risk.”
Others include power grid constraints, coordination with local residents, environmental assessment and compliance with relevant regulations. The Japan Oil, Gas and Metals National Corp., which operates under the Ministry of Economy, Trade and Industry, carries out surveys of geothermal resources by helicopter. If a promising site is identified, the corporation conducts a heat flow drilling survey to get data about the structure and the temperature underground. That information is provided free of charge to geothermal developers.
In 2016, the corporation established an Advisory Committee for Geothermal Resources Development. Its aim is to help local governments play a bigger role in developing and managing geothermal resources.
Yasukawa says the biggest potential of geothermal energy lies in development of “supercritical” resources at depths of 4 to 5 kilometers in subduction zones — areas where tectonic plates meet and one plate moves under another, and is forced by gravity into the Earth’s mantle.
“We think we have this kind of geothermal reservoir in Tohoku,” she says. Here, subterranean seawater is in a supercritical condition of high pressure and high temperature.
“The chemistry is very hard to handle,” Yasukawa says. “It’s very acidic, so it’s very hard to develop. We have to develop new tools, methods and materials.” This work is being funded by the Ministry of Economy, Trade and Industry’s New Energy and Industrial Technology Development Organization.
Other promising areas being looked into include binary geothermal power, which uses ammonia vapor produced when hot-spring water reaches a temperature close to 100 degrees Celsius, and hot dry rock power, in which water that is poured into cracks in the ground is turned into steam on contact with hot rocks 2 to 3 kilometers underground.
Ishimaki says priorities for the geothermal sector include:
• Improving exploration accuracy through seismic surveys to image structure of geothermal reservoirs;
• Reducing drilling costs by developing polycrystalline diamond compact bit cutters; and
• Stabilizing the flow of geothermal fluids through artificial-recharge and reservoir-management technology.
Ironically, three Japanese companies — Toshiba Corp., Mitsubishi Heavy Industries Ltd. and Fuji Electric Co., Ltd. — hold about 70 percent of the global market for the development of geothermal turbines.
Japan obviously has the scientific and technological skills needed to make full use of its untapped geothermal potential. What’s missing is the political will and leadership needed to make Inoue’s “Kirikirijin” more than just a pipe dream.
BySteveMcClure via JT