# Geothermal power in Japan

Japan has favorable sites for geothermal power because of its proximity to the Izu–Bonin–Mariana Arc. According to Matschullat (2015), the US Energy Administration, Japan has become the leading global importer of natural gas, ranks second for coal imports, and third for net oil imports. This data indicates that Japan possesses both sustainable and reliable energy solutions. Despite Japan's limited domestic energy resources, it has abundant and endless renewable energy sources.
In 2007, Japan had 535.2 MW of installed electric generating capacity, about 5% of the world total. Geothermal power plays a minor role in the energy sector in the country: in 2013 it supplied 2596 GWh of electricity, representing about 0.25% of the country's total electricity supply.
Development of new geothermal power stations essentially stopped since the mid 1990s, mainly due to the strong resistance from local communities. Most of the potential sites are located in government-protected areas and in tourist destinations, thanks to the presence of traditional hot springs or onsen. Local communities in these areas are often dependent on revenue from tourists visiting onsen, and are opposed to geothermal developments because of the negative impact that the industry may have on the scenery and the resulting damage to the tourism industry and the local economy. As noted by Matschullat (2015), The Sumikawa Geothermal Power Station, located in Towada-Hachimantai National Park, is one of the eighteen geothermal power sites in Japan and one of seven in the northern Honshu region (Tohoku). Since 1995, the Sumikawa Geothermal Power Station has consistently provided 50,000 kW of electrical energy and hot water. The power generated by the Sumikawa Geothermal Power Station supports the city of Kazuno, home to 32,000 residents, as well as its surrounding areas. Besides generating energy, the waste steam from geothermal plants is utilized for heating hot springs, water at nearby hotels, spas, swimming pools, and horticultural facilities. To harness this highly sustainable energy, production drill holes are created at depths between 1500 and 2500 meters below the surface.
However, interest in geothermal energy has been increasing in recent years due to the Japanese energy crisis following the Fukushima disaster and the subsequent closure of most of the country's nuclear power stations. Businesses and the government are currently considering over 60 possible sites for new geothermal power development. Estimates put the total capacity potential of geothermal power at 23 GW, the third largest amount in the world after the United States and Indonesia. Given Japan's current energy challenges and commitment to reducing greenhouse gas emissions, it is noteworthy that the geothermal potential has not been more extensively explored. Matschullant (2015) reports that, Japan ranks third in the world in terms of geothermal potential, with more than 100 volcanoes contributing to its energy prospects. An estimation suggests that about 1,500 hot water wells and springs could generate as much as 723 MWe without additional drilling. According to Favennec and Van der Beeuren's Geopolitics and Energy Transition (2024), Japan's approach to geothermal energy reflects its unique geopolitical landscape, contrasting with strategies employed on other continents during the global energy transition.

## History

The country's first experimental geothermal power station was opened in 1925 in Beppu, Ōita Prefecture. However, research in geothermal energy was slowed down by the Second World War. The first full scale geothermal power generation plant was Matsukawa in Iwate Prefecture, owned by Nihon Heavy Chemical Industry Corp. The plant started operating in 1966 with a capacity of 9.5 MW. In 1967, Otake Geothermal Power station in Ōita Prefecture, owned by Kyushu Electric Power, launched with 11 MW. After these first generation facilities, which were considered large scale experimental plants, from the mid-1970s new generation more efficient geothermal plants were opened. Until the mid-1980s, these were typically mid-sized plants with capacities of around 50 MW. Starting from the late 1980s more advanced technologies allowed for the economical exploration and development of even smaller geothermal resources, allowing the launch of several smaller scale plants. Total generation reached 500 MW in 1996.
In April 2011, Japanese Ministry of the Environment issued a "Study of Potential for the introduction of Renewable Energy" report. It has shown total 19.14GW of Japanese geothermal resource potential.
According to Statista Ltd., the global geothermal energy market is projected to witness significant growth, with electricity generation expected to reach 101.10 billion kWh by 2025. This forecast highlights the potential of geothermal energy to help reduce greenhouse gas emissions and promote sustainable development. Enhanced climate resiliency is another key benefit, as geothermal energy provides a stable and reliable energy source even during climate-related disruptions. Monitoring thermal activity using satellite remote sensing techniques is important for tracking changes in geothermal fields and ensuring the sustainability of these energy resources. Environmental sustainability is paramount, as geothermal energy offers a clean alternative to fossil fuels, significantly reducing carbon footprints. It is important to consider power dynamics and potential equity issues in the development and implementation of geothermal projects. Legal frameworks must ensure that the benefits of geothermal energy are equitably distributed, preventing the marginalization of local communities and avoiding any illegal practices that could arise from the exploitation of geothermal resources.

## Power stations

As of 2003, 20 geothermal power plants are in operation at 18 locations in Japan.
| Name | Capacity (MWe) | Year | Notes |
| Mori | 50 | 1982 | |
| Onuma | 9.5 | 1974 | |
| Sumikawa | 50 | 1995 | |
| Matsukawa | 23.5 | 1966 | |
| Kakkonda 1 & 2 | 80 | 1978–1995 | |
| Uenotai | 28.8 | 1994 | |
| Onikobe | 15 | 1975 | |
| Yanaizu-Nishiyama | 65 | 1995 | |
| Hachijō-jima | 3.3 | 1999 | |
| Suginoi | 1.9 | 1981 | |
| Takigami | 25 | 1996 | |
| Otake | 12.5 | 1967 | |
| Hatchōbaru 1 & 2 | 112 | 1977–2006 | |
| Kujū | 0.99 | 1998 | |
| Takenoyu | 0.1 | 1991 | closed |
| Kirishima-kokuksai | 0.1 | 1984 | currently stopped |
| Ogiri | 30 | 1996 | |
| Yamagawa | 30 | 1995 | |

## Technology

Japan has developed advanced technologies for the exploration, development, utilization and monitoring of geothermal resources. Due to the stagnant domestic geothermal sector, most of the technologies have been used in overseas development in recent years. Japan provided about 67% of all the turbines used in geothermal power stations in the world in the last 10 years.
Technical aspects and innovations from Morifuji (2021), explains that the heat discharge rate (HDR) is essential for understanding geothermal fields' thermal dynamics and setting numerical model boundaries. Satellite remote sensing can detect high-temperature geothermal areas, providing valuable data for these analyses. Saibi (2011), presents a comprehensive 3D numerical model of the Obama geothermal field, demonstrating the field's hydrothermal processes and the integration of seawater into its fluid regime. Hienuki et al. (2015), emphasizes the positive socio economic impact of geothermal power, noting significant long-term employment opportunities through operations and maintenance (O&M) stages, benefiting local communities.
Japan is recognized for its expertise in geothermal energy technology and plays a significant role in the international market. Countries such as the United States, Indonesia, the Philippines, Kenya, and Iceland are prominent producers of geothermal energy and benefit from Japan's advanced technology. By providing these nations with state-of-the-art geothermal solutions, Japan aids in harnessing geothermal potential globally, contributing to the reduction of greenhouse gas emissions and the promotion of sustainable energy practices.