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JAPAN claims to be desperately short of natural resources but many scientists
and engineers believe that the government is ignoring one of its most important
assets – geothermal energy. By tapping the vast reservoirs of superheated
water and steam that lie beneath Japan’s seismically lively archipelago,
the country could provide a fifth of its energy needs. The technology has
been around for a long time; the problems involved are not technical, but
political.

Japan has nine geothermal power stations, reaching from the northern
island of Hokkaido to Kyushu in the south, with a total electrical capacity
of some 214 megawatts. The plants run on superheated pockets of steam, buried
between 300 and 2800 metres below the surface at temperatures of around
150 Degree C. The steam, piped to the surface, drives turbines in the conventional
way to generate electricity.

The first geothermal plant, at Matsukawa in northern Honshu, was commissioned
in 1966. Most of the rest came on stream after the oil crisis of the early
1970s, which accelerated Japanese research and exploration for geothermal
energy.

Today, three Japanese organisations are involved in studying and developing
geothermal energy. They depend on donations from private industry, plus
a subsidy from MITI which amounts to about 16 billion yen (Pounds sterling
72 million) this year. Most geologists and engineers involved in the research
feel that they need more money to get results, especially in techniques
for heating buildings with geothermal energy. According to Shiro Tamanyu,
a geologist with the Geothermal Department of the Geological Survey, Japan
is lagging behind countries such as France and Iceland.

In Tamanyu’s view, ‘Japan could derive up to 20 per cent of its energy
needs from geothermal energy.

Susumu Nakagawa, a geologist and consulting engineer in geothermal power
at the New Energy Foundation, one of the three organisations supported by
MITI, agrees that research deserves more support. ‘With enough money, the
potential is very large,’ he says.

Yet estimates from the Geothermal Energy Division at Japan’s Ministry
of International Trade and Industry (MITI) suggest that, by the turn of
the century, energy from geothermal sources will generate only 0.8 per cent
of Japan’s electricity. Today it accounts for 0.2 per cent. Tetsuo Noguchi,
the head of the division, says that there are not only some technical problems
to overcome, but also opposition to exploiting geothermal energy for generating
electricity. The opposition comes from the owners of Japan’s 2189 commercial
spa baths, known as onsen (hot springs).

These traditional bathhouses hold a strong place in Japanese society.
They are places to go and relax with friends or to cure aches and pains,
and nowadays often form part of large hotels and leisure complexes. The
operators of the onsen fear that piping geothermal heat into power stations
will destroy their sources of hot water, and they have the political clout
to ensure that their voices are heard.

It is difficult to prove the onsen industry’s claims of water loss because
the level of hot water depends on many changing factors such as local seismic
activity and rainfall. Noguchi, however, says that there has not been a
single documented case of an onsen losing water near a geothermal power
station. Where less conservative bathhouse owners have agreed to cooperate,
geothermal plants have extracted superheated steam to drive turbines and
then passed the water, still at temperatures more than high enough to satisfy
customers, to the onsen.

Another hurdle for geothermal energy is that it is very expensive to
build the power stations. A 50-megawatt plant, for example, would cost about
25 billion yen, or about 500 000 yen per kilowatt of capacity. In Japan,
a nuclear power plant costs around a fifth less than this. Nuclear electricity
is also cheaper to generate: 10 yen per kilowatt-hour, as opposed to 12
to 15 yen per kilowatt-hour for the geothermal equivalent. However, research
into the principles of hydrology and new techniques of drilling are bringing
costs down.

Mitsubishi Metals, for example, built its Ohnuma plant in northern Honshu,
13 years ago at a cost of 3.2 billion yen, to supply electricity to a smelter.
The plant has a capacity of 10 megawatts, working out at around 320 000
yen per installed kilowatt. Yasunori Sakai, manager of geothermal energy
at Mitsubishi Metals, says that electricity from the plant now costs around
6 yen per kilowatt-hour. ‘If we were to buy it commercially, it would cost
about 10 yen per kilowatt-hour,’ he says. The company is now planning another
geothermal plant with five times the output, which it will feed into the
local electrical grid.

The plant at Ohnuma is a good example of what can be done with careful
research. It injects water back into the reservoir to prevent land subsidence,
and nearby onsen suffer no loss.

Most geologists agree that if the owners of the bathhouse and the national
park agencies, which control some of Japan’s best hot-spring land, cooperate
fully, the potential for geothermal energy in Japan is about 30 000 megawatts,
enough to replace perhaps 23 nuclear power stations.