Japanese spa town in a lather over geothermal plans

Residents concerned power plant will compromise integrity of ancient spring

In pictures: Kusatsu's hot water
Hot Springs in Kusatsu, Japan
Hot steam rises from the Yubatake 'Field of Hot Water' spring in the centre of Kusatsu town, Japan Photograph: Jeremy Sutton-Hibbert

A deep breath is all that's needed to appreciate why Kusatsu is ideally suited to lead Japan's quest for new sources of renewable energy.

As the steam rises from myriad holes in the ground, the air is filled with the unmistakable stench of sulphur. The pong is inescapable - it hangs on your clothes for days - but the volcanically heated water that creates it is the lifeblood of this spa town 90 miles northeast of Tokyo.

As Japan seeks new ways to honour its Kyoto protocol commitments on CO2, Kusatsu's bathers are up in arms over plans to tap into rich reservoirs of geothermal energy, a move they say threatens their inalienable right to soak in the restorative waters of a natural spa.

In April a government panel of industry experts and academics is expected to call for substantial investment in geothermal plants for the first time in more than two decades.

The envisioned new generation of power plants will tap into Japan's vast supply of heated water and steam, nestling deep below ground and sustained by the country's 108 active volcanoes.

The result, the government says, will be an inexhaustible supply of cheap, clean energy that will also ease the country's $183bn a year dependence on Middle East oil.

Geothermal developers insist that power plants and Japan's thousands of spas - or onsen - can happily coexist.

But the 7,400 people of Kusatsu, more than 90% of whom depend on the tourist trade for their living, are not convinced.

The fear that energy development will rob the town of its precious supply of hot, mineral-rich water has propelled them to the forefront of the anti-geothermal movement.

Their nemesis is the nearby village of Tsumagoi, whose mayor has proposed the construction of a geothermal plant 4km from its nervous neighbour.

"It is one thing to achieve global standards on the environment, but does that mean we have to destroy thousands of years of culture to achieve it?" says Kusatsu's mayor, Takashi Nakazawa. "We are representing every threatened onsen in Japan. There are thousands of other places they could build a geothermal plant. We are very lucky to have this natural resource and we want to use it to bring more people to our town, not throw it away."

Kusatsu's revered hot springs are fed by water resting deep underground and kept at a piping-hot 54C by the 2,160-metre volcano Mount Shirane. The water, which gushes out of the ground at a rate of 34,000 litres a minute, is then cooled for the benefit of the three million bathers who visit the town every year.

Unlike many other spas, the water rises to the surface naturally and is used to heat schools, homes and roads during the town's bitterly cold winters.

The spa was discovered 1,800 years ago, according to local legend, and by the Edo era the shogun Tokugawa Yoshimune had Kusatsu water delivered to the capital.

Though faced with centuries of tradition and legions of irate bathers, Japan's power companies view geothermal power as a potential bonanza at a time when plans to dramatically increase nuclear power have fallen foul of accidents and opposition from towns near the proposed sites of new reactors.

Japan's 18 geothermal plants account for a mere 0.2% of total electricity output, according to the trade and industry ministry. But scientists believe the sector's share could rise significantly if the envisaged plants are built.

Critics say Kusatsu's businesses are guilty of squandering much of the potential energy, lost when the water is allowed to cool before being released into dozens of bathhouses and ryokan inns.

"In Japan, the steam used in geothermal power generation is turned to water and returned underground," Yuzuru Ashida, a professor at Kyoto University who has advised the Tsumagoi town government, told the Yomiuri Shimbun. "There is no scientific proof that geothermal power generation negatively impacts hot springs."

After failing to secure government subsidies last year, Tsumagoi has put its plans on hold.

But with official enthusiasm for geothermal power about to reach boiling point, the residents of Kusatsu say the battle to save the historic waters is far from over.