Research and Development of Geothermal Energy Generation Technologies

Given the desire for increased introduction of renewable energy, hopes are riding on the utilization of geothermal power generation in Japan, which possesses the world's third largest geothermal resource potential. In addition—unlike solar and wind power—stable output has been achieved for geothermal power, so it is attracting considerable attention as a base load power source.

In recent years, progress has been made in terms of new large-scale geothermal development in the Wasabisawa and Akinomiya regions of Akita Prefecture, the Appi region of Iwate Prefecture, and elsewhere. In addition, Medipolis Ibusuki power station, Sugawara binary power station, Takigami binary power plant, and others have started binary power generation operations.

At the same time, according to the 2017 Report of the Geothermal Power Promotion Society (Ministry of Economy, Trade and Industry), as of the end of FY2017—even if all geothermal development projects are included, regardless of whether they are at the initial-survey or development stage—total output is only around 320,000 kW. To achieve the FY2020 geothermal power goal, additional projects equivalent to around 600,000 kW are necessary.

In addition, many geothermal resources are located within natural parks. There are many important issues that need to be addressed in order to promote development within such parks, including the necessity of pursuing environmentally friendly efforts, the establishment of specific rules for development, and the improvement of environmental-conservation technology.

Furthermore, examples of small-scale geothermal power generation by utilizing existing hot spring wells are increasing little by little. There are also successful examples of the utilization of heat in combination with power generation which are contributing to the development of local industries, including agriculture in particular. These efforts contribute to the development of local economies and offer possible solutions in cases where it is difficult to achieve consensus between the geothermal development and hot springs industries. Therefore, it is considered important to demonstrate successful results such as those described above in order to promote geothermal development in areas where hot springs are located.

In addition, a decrease in the power generating capacity of existing geothermal power plants is a major issue, so efforts are also necessary in terms of developing technology that contributes to the restoration, maintenance, or improvement of the capacity of such plants.

Therefore, this project is focused on promoting the increased introduction of geothermal power generation in Japan by examining the following areas to more effectively utilize geothermal resources:

• Developing equipment for environmentally-friendly, high-performance geothermal power generation systems
• Developing binary power generation systems in the low-temperature range
• Developing technology that contributes to the facilitation of environmental assessments and environmental conservation measures
• Developing technology aimed at the advanced utilization of power plants
• Developing technology aimed at more advanced utilization of geothermal energy