Geothermal Energy
Geothermal Power Plants in Japan

Japan is one of the most distinguished volcanic countries in the world, and geothermal energy is its precious domestic energy. And as it emits very little CO2, it is also regarded as an effective means to deal with global warming issues as well as wind and small-to-medium scale hydroelectric power. However, geothermal energy has some difficult tasks. The initial investment cost is huge, and some measures are indispensable for preservation of natural scenery around the development site, and guarantee of the hot-spring utilization without any influence.

In Japan, actual survey for geothermal energy resources has begun around 1950, and the first geothermal power station started its operation in 1966. After 35 years, 16 geothermal power plants in the 14 geothermal power station sites (excluding small power generation facilities for household use) are currently operating in Japan. Total authorized rated output reaches 530 MW, or 0.2% of the whole Japanese power capacity of 250 GW. Actual power output of the geothermal power for FY 1999 was 3,440 GWh, and this is account for 0.3% of 1,000 TWh, the whole power output in Japan. Japanese geothermal power generation capacity accounts for 6% in the world and ranks sixth, following USA, the Philippines, Italy, Mexico and Indonesia.

Besides power generation, heat of geothermal energy itself is directly used. Heat of hot spring is utilized as heat source of air conditioning, greenhouses, fish culturing, thawing on road, and hot water supply for some facilities including swimming pool. Total amount of direct heat consumption in Japan reaches 1,000 TJ. Recently, sub-underground heat, which maintains even temperature throughout the year, is drawing public attention as a stable heat source. The sub-underground heat is utilized with geothermal heat pump or ground source heat pump for air conditioning. In Japan, seasonal variations in temperature are marked, and constant heat demands exist throughout the year. Further, heat use is considered as an effective measure to mitigate heat island phenomena in the urban area.