Small Capacity Geothermal Binary Power Generation System

Japan is a volcanic country having abundant geothermal resources. To date, Japan has 20 geothermal power generation facilities, with a total installed capacity of 550 MW. Most of these facilities are large capacity geothermal power plants constructed by utility power companies, but due to various circumstances, there are no further plans to build large capacity plants in the near future. The New Energy and Industrial Technology Development Organization (NEDO) is continuing its program of Geothermal Development Promotion Surveys, which since 2003 have targeted the development of small and medium capacity resources. There are many high temperature wells and steam discharge sites in Japan which are not utilized. Various studies are being carried out to expand the usage of such geothermal energy sources that are not currently utilized for domestic energy generation. Efforts are underway to promote the use of natural resource-based energy systems, including geothermal energy, and this initiative is known as EIMY (energy in my yard). In addition, RPS (renewable portfolio standard) legislation mandating the utilization of electricity generated from renewable energy has been enacted in many countries. In Japan, the RPS became effective in April 2003. The renewable energy required for use in accordance with the RPS includes geothermal energy. Consequently, utilization of low temperature geothermal resources for electricity generation, which was not considered previously, is now being planned. For small scale or low temperature geothermal resources, it is sometimes more economical to use a binary power generation system having a lower boiling point medium than that of conventional geothermal steam turbines. In consideration of these circumstances, Fuji Electric is developing a small capacity geothermal binary power generation system.