IAVCEI 2013 Scientific Assembly - July 20 - 24, Kagoshima, Japan
Forecasting Volcanic Activity - Reading and translating the messages of nature for society

1A1_1E-O7

Room A3

Date/Time: July 21 10:15-10:30

A business model of hot spring power generation and its current progress in Japan
Hirofumi Muraoka1 , Seiichiro Ioka1 , Norio Yanagisawa2 , Munetake Sasaki2 , Hajime Sugita2 , Masatake
Sato3 , Kazumi Osato3
1

North Japan Research Institute for Sustainable Energy (NJRISE), Hirosaki University, Japan, 2 Institutefor Geo-Resources and Environment (GREEN), AIST, Japan, 3 Geothermal Energy and Development
Co., Ltd. (GERD), Japan
E-mail: hiro@cc.hirosaki-u.ac.jp

A business model of hot spring power generation was proposed by Muraoka (2007) and Osato and Muraoka(2008) to efficiently utilize low-temperature hydrothermal resources such as the numerous hot springs in Japan.
About 28,000 hot spring sources are distributed all over Japan and their pre-existence is one of the serious
barriers to develop new geothermal power plants in Japan. However, current binary cycle technology enables
power generation by hot spring water even less than 100°C. Most of high-temperature hot springs are mainly used
for bathing in Japan until the present where they have to be cooled down to the adequate bath temperature 42°C
without any serious dilution of balneological constituents. It means that high-temperature hot springs need moreworks in terms of the bath use compared to the moderate-temperature hot springs. Then, we proposed to introducea very small binary cycle in the upper reach of high-temperature hot springs. If we do that, we could make power
generation with the high-temperature range above the bath-use temperature and we could make the cooling down
to the adequate bath use temperature without any serious dilution of balneological constituents at the same time.
This is our business model of hot spring power generation. This business model gives a further merit, that is, if hotspring owners adopt the business model of hot spring power generation, the conflict between hot spring owners
and geothermal power development will be gradually reduced, because the hot spring power generation itself issome sort of geothermal power development. At the time of the proposal, we did not have any small binary cycle
power generation systems suitable for the small discharge rate of hot springs and therefore we made our efforts
to develop a 50 kW class Kalina cycle hot spring power generation system. This system was almost completed
and is now under the operation experiment in the Matsunoyama hot spring field, Niigata Prefecture. In addition tothis, many makers recently manufactured small-scale binary cycle power generation systems such as 70 kW, 50kW, 20 kW and 3 kW classes in Japan. The feasibility studies of hot spring power generation are recently made in
Niigata, Shizuoka, Nagasaki, Oita, Nagano, Toyama and Aomori Prefectures. The profitability of hot spring power
generation is still marginal even by the new Feed-in Tariff system at 42 Yen/kWh introduced in July 2012, but thehot spring power generation market will be established within the coming ten years.
References: Muraoka, H. (2007) Current withering and possible future revival of geothermal energy development
in Japan. Journal of the Japan Institute of Energy, 86, 153-160 (in Japanese with English abstract). Osato, K. andMuraoka, H. (2008) Hot spring binary cycle power generation. Journal of the Japan Institute of Energy, 87, 812-818(in Japanese with English abstract).

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