10:10 AM - 10:30 AM
[U05-04] Current status and issues of geothermal utilization
★Invited Papers
Keywords:Geothermal power plant, New Zealand, Volcano, hot spring
1. Introduction
When using geothermal energy as a renewable energy source, stable power generation can be expected throughout the year, regardless of weather conditions. In addition, greenhouse gas emissions are extremely low. Then, geothermal energy is being developed as a baseload power source, mainly in volcanic countries.
2. History of geothermal power generation development
In Japan, research and development progressed rapidly from 1970s, and total power generation reached 52MW until 1996. But new development has stagnated due to issues such as a decrease in the national budget, development restrictions within national parks, the difficulty of coexisting with hot springs, and the need for large development investments.
After 2011, policies repromote geothermal power generation. For example, along with the introduction of Feed-in Tariff, the shortening of the environmental assessment period. At the same time, research is being conducted on EGS and supercritical geothermal energy for future technologies.
3. Progress and challenges of geothermal power generation since the earthquake
At 2019, 45MW size geothermal power plant started at Wasabizawa and there are several geothermal power plants with a capacity around 5MW. And there are more than 100 new geothermal power generation facilities as small-scale binary power plants using hot spring exhaust heat.
The advantages of developing small-scale binary power generation are that it is easy to gain the understanding of hot spring owners because it does not affect the hot spring production, the lead time is short, and the FIT price is high. However, the total increase in facility capacity by small binary power generation is only about 50 MW. And at several geothermal power plants that began operation by the 1990s, the output is declining. In order to increase geothermal power generation as a renewable energy source in the future, it is necessary to build new large-scale power plants and restore the output of existing geothermal power plants.
4. Comparison between Japan and New Zealand
Japan's geothermal resource potential is estimated at about 23,500MW based on the number of active volcanoes, ranking third in the world. However, Japan's current geothermal power generation capacity is about 550MW, ranking 10th. In case study, we would like to compare Japan with New Zealand, which is a volcanic island nation like Japan and has a similar area and latitude.
The current installed capacity of geothermal power plants in New Zealand is about 1,064MW, about twice that of Japan. In addition, the turbines of New Zealand's geothermal power plants are large. For example, the Nga Awa Purua Geothermal Power Plant has the world's largest geothermal turbine at about 139MW. The amount of geothermal power generated per site is relatively larger in New Zealand, and production is stable. The reason for this is that the Taupo volcanic belt, where many geothermal power plants in New Zealand are located, is located in the Taupo Rift, and geothermal fluid at about 300°C is stored in a porous aquifer made of Quaternary volcanic and sedimentary rocks at 1km depth. This makes it easy to develop large-scale geothermal power plants.
In addition, the social situation is also easier for geothermal development in New Zealand than in Japan. For example, shorter lead time than Japan; thorough environmental monitoring by local governments; coexistence Maori culture; geothermal related companies have good collaboration with academic and research organizations such as the University of Auckland and GNS Science.
5. Conclusion
Japan's geothermal power generation capacity is low compared to its geothermal potential. However, potential surveys of promising areas are progressing rapidly, and Japan has the world's top share of technologies such as power generation turbines, so it is expected that the use of geothermal power will be promoted in the future.
When using geothermal energy as a renewable energy source, stable power generation can be expected throughout the year, regardless of weather conditions. In addition, greenhouse gas emissions are extremely low. Then, geothermal energy is being developed as a baseload power source, mainly in volcanic countries.
2. History of geothermal power generation development
In Japan, research and development progressed rapidly from 1970s, and total power generation reached 52MW until 1996. But new development has stagnated due to issues such as a decrease in the national budget, development restrictions within national parks, the difficulty of coexisting with hot springs, and the need for large development investments.
After 2011, policies repromote geothermal power generation. For example, along with the introduction of Feed-in Tariff, the shortening of the environmental assessment period. At the same time, research is being conducted on EGS and supercritical geothermal energy for future technologies.
3. Progress and challenges of geothermal power generation since the earthquake
At 2019, 45MW size geothermal power plant started at Wasabizawa and there are several geothermal power plants with a capacity around 5MW. And there are more than 100 new geothermal power generation facilities as small-scale binary power plants using hot spring exhaust heat.
The advantages of developing small-scale binary power generation are that it is easy to gain the understanding of hot spring owners because it does not affect the hot spring production, the lead time is short, and the FIT price is high. However, the total increase in facility capacity by small binary power generation is only about 50 MW. And at several geothermal power plants that began operation by the 1990s, the output is declining. In order to increase geothermal power generation as a renewable energy source in the future, it is necessary to build new large-scale power plants and restore the output of existing geothermal power plants.
4. Comparison between Japan and New Zealand
Japan's geothermal resource potential is estimated at about 23,500MW based on the number of active volcanoes, ranking third in the world. However, Japan's current geothermal power generation capacity is about 550MW, ranking 10th. In case study, we would like to compare Japan with New Zealand, which is a volcanic island nation like Japan and has a similar area and latitude.
The current installed capacity of geothermal power plants in New Zealand is about 1,064MW, about twice that of Japan. In addition, the turbines of New Zealand's geothermal power plants are large. For example, the Nga Awa Purua Geothermal Power Plant has the world's largest geothermal turbine at about 139MW. The amount of geothermal power generated per site is relatively larger in New Zealand, and production is stable. The reason for this is that the Taupo volcanic belt, where many geothermal power plants in New Zealand are located, is located in the Taupo Rift, and geothermal fluid at about 300°C is stored in a porous aquifer made of Quaternary volcanic and sedimentary rocks at 1km depth. This makes it easy to develop large-scale geothermal power plants.
In addition, the social situation is also easier for geothermal development in New Zealand than in Japan. For example, shorter lead time than Japan; thorough environmental monitoring by local governments; coexistence Maori culture; geothermal related companies have good collaboration with academic and research organizations such as the University of Auckland and GNS Science.
5. Conclusion
Japan's geothermal power generation capacity is low compared to its geothermal potential. However, potential surveys of promising areas are progressing rapidly, and Japan has the world's top share of technologies such as power generation turbines, so it is expected that the use of geothermal power will be promoted in the future.