Survey of Energy Resources 2007
Geothermal Country Notes
Japan has a long history of geothermal utilisation, both direct and for power generation. It is one of the world leaders in terms of generation of electricity. The first experimental power generation took place in 1925, with the first full-scale commercial plant (23.5 MWe) coming on-line at Matsukawa, in the north of the main island of Honshu, in 1966. Following each of the two oil crises, development of Japan's geothermal resources was accelerated and by end-1984, 314.6 MWe capacity had been commissioned. Growth continued and unit size decreased as technological improvements occurred. By end-2003, installed capacity stood at 535.25 MWe (consisting of 20 units at 18 locations). The existing plants are all located in the Tohoku region of northern Honshu and on the southern island of Kyushu.
The country's geothermal potential is estimated to be in the order of 24.6 GWe. Only a small fraction of this potential has been used to date and until ways of tapping Japan's deep resources can be developed, this situation will prevail. In 2000 the planned government deregulation of the electricity sector took place. This was followed in 2003 by the Special Law Concerning the Use of Renewable Energy by Electric Utilities - a method for the encouragement of generation from renewable energies by means of a renewable portfolio standard (RPS). In the case of geothermal, the RPS is confined to binary-cycle plants.
In recent years, development of electricity generating plant has been slow but at the beginning of 2004 a 2 MWe power unit was installed at the Hatchobaru power station - the first binary-cycle plant in Japan.
Direct use of geothermal hot water has a long tradition in Japan, where enjoyment of natural baths (more than 25 000) is a national recreation. In 2005 it was estimated that total installed capacity for direct use totalled more than 400 MWt (excluding recreational hot-spring bathing). Of the total, hot water supply and swimming pools account for 26%, space heating 25%, snow melting 23%, greenhouse heating 11%, air-conditioning/cooling 10% (70%-30% split), fish breeding 4%, ground heat uses (including heat pumps) 1% and industrial and other uses negligible.