Presentation Information
[O02-05]Current status and issues of geothermal utilization★Invited Papers
*Norio Yanagisawa1 (1.Geoinformation Services Center, Geological Survey of Japan, National Institute of Advanced Industrial Science and Technology)
Keywords:
Geothermal power plant,Geo-heat pump system,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. Geo-heat pump system
While the use of geothermal power is limited to volcanic regions (countries), geo-heat pump system is becoming increasingly popular worldwide, particularly in Europe and the United States. This method utilizes the fact that temperatures several dozen meters underground remain nearly constant year-round to efficiently provide air conditioning in the summer. Its advantages include:
- It can be used anywhere in Japan, at any time.
- It saves electricity, energy, and reduces CO2 emissions.
- It can be used in environments where outdoor temperatures below -15°C are insufficient for conventional air conditioners (air-source heat pumps).
- Because the geot-heat exchanger is sealed, there is no risk of environmental pollution.
- It contributes to mitigating the heat island effect by not releasing heat outdoors.
As an example, in an office building in central Tokyo, when the air conditioning system was upgraded from an air-source heat pump (conventional air conditioner) to a geo-heat pump, a comparison of the actual electricity consumption of air-source and geo-heat pumps revealed a 49% annual energy savings, with the energy savings being particularly significant in the summer.
Despite this, the introduction of geo-heat pump system in Japan is lagging far behind that of several countries such as the United States, China, and Sweden, with the number of installations at less than 1/100. One reason for this is the high cost of drilling. To promote geo-heat pump system, several local governments are currently creating maps of the potential map, and we can look forward to its future spread.
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. And we have to effort to promote geo-heat pump systems.
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. Geo-heat pump system
While the use of geothermal power is limited to volcanic regions (countries), geo-heat pump system is becoming increasingly popular worldwide, particularly in Europe and the United States. This method utilizes the fact that temperatures several dozen meters underground remain nearly constant year-round to efficiently provide air conditioning in the summer. Its advantages include:
- It can be used anywhere in Japan, at any time.
- It saves electricity, energy, and reduces CO2 emissions.
- It can be used in environments where outdoor temperatures below -15°C are insufficient for conventional air conditioners (air-source heat pumps).
- Because the geot-heat exchanger is sealed, there is no risk of environmental pollution.
- It contributes to mitigating the heat island effect by not releasing heat outdoors.
As an example, in an office building in central Tokyo, when the air conditioning system was upgraded from an air-source heat pump (conventional air conditioner) to a geo-heat pump, a comparison of the actual electricity consumption of air-source and geo-heat pumps revealed a 49% annual energy savings, with the energy savings being particularly significant in the summer.
Despite this, the introduction of geo-heat pump system in Japan is lagging far behind that of several countries such as the United States, China, and Sweden, with the number of installations at less than 1/100. One reason for this is the high cost of drilling. To promote geo-heat pump system, several local governments are currently creating maps of the potential map, and we can look forward to its future spread.
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. And we have to effort to promote geo-heat pump systems.