再生エネルギー研究センターパンフレット（英語）

12/20

11Geothermal Energy Team－Technologies for the Effective and Sustainable Use of Geothermal Resources－Japan has many volcanoes and a vast amount of geothermal energy. Geothermal energy contribute to thestable power without effects of weather conditions. Geothermal energy has a potential to cover a base load power.Research Target　The team is conducting research and development to sustainably utilize geothermal energy on a suitable scale and in a proper style conforming to underground conditions and social situations with the following keyword: “Proper use of geothermal energy.” In the short term, the team is aiming to make direct contributions to the sustainable power generation and the increase in its amount through the development of monitoring system for coexistence of geothermal power generation with hot springs and the advanced monitoring of the change in the reservoirs. In the long term, furthermore, the team will make geothermal energy available on a large scale as a base load power source by developing an innovative power generation technology through the use of supercritical geothermal resources originating from the subduction zone and the derivation of a method for the social implementation of geothermal energy.A need for studying and developing geothermal energyRoad mapResearch Outline　The team is conducting various projects commissioned by the national government, private companies, and others to establish the proper utilization of geothermal energy in Japan. The team also conducts various basic studies in geosciences to improve the scientific understanding of geothermal systems. Since the underground is invisible and the properties of the geothermal resources largely depend on the specific areas, it is very important to acquire actual data in the field and conduct studies based on them in geothermal studies. The team, therefore, conducts field experiments, monitoring, equipment testing, etc. at many field sites mainly in the Tohoku region. 　The team mainly aims to accomplish the following goals:●Understanding and visualizing the phenomena that occur in the reservoir by developing a sensing system for monitoring geothermal energy using Micro Electro Mechanical Systems (MEMS), optical fibers, etc. and by developing advanced analysis technologies such as transient multicomponent signal processing and integrated interpretation method.●Compiling huge amounts of geothermal resource information possessed by AIST into an advanced database, presenting optimal development methods, and achieving the coexistence with hot springs by developing a geothermal energy simulator.●Developing an optimal creation and control technology of a reservoir using hydraulic stimulation and fluid injection. This allows us to derive a universal development and utilization method.●Exploring the possibility in developing supercritical geothermal resources originating from the subduction zone and making it available for large-scale base-load power generation in 2040.Concept of a supercriticalgeothermal systemDistribution of old caldera(Oyagi, 2003)The results of seismic and other analyses suggest the existence of magma-originated volcanic complexes containing about 1% of the supercritical fluid beneath the old caldera (4-5 km). There are more than 50 old calderas in the Tohoku region.The team proposed the possibility of generating several 10 GW-several 100 GW power by exploiting a supercritical geothermal resource originating from the subduction zone. The team is drawing out a research plan to make this geothermal resource available as a base-load power source in 2040.High-temperature hot springsStratovolcanoCalderaLow permeability rockMagma reservoirSlabBrittle zonelithostatic pressure equilibriumHot fluid upward flowTarget of this studyHydrostatic equilibriumNatural hydrothermal system2015FY2020FY2030FYDevelopment of monitoring and simulation technologiesDemonstration of the potential for developing supercritical geothermal resources originating from the subduction zoneDerivation of a high-resolution and high-reliability method for reservoirmonitoringRealizing innovative large-scale geothermal power generationBuilding a method to implement geothermal power generation in into societyTechnical support for companies in the disaster-affected areasResearch and development of innovative technologies originated from JapanSecuring the international advantages of JapanPromoting geothermal energy-related industries in the disaster-affected areasDevelopment of a geothermal energy simulatorDirect contribution for increasing amounts of power generation and for maintaining its sustainabilityImproving the reliability of geothermal power generationIntegrated understanding of a geothermal systemSubduction zones100- 200kmAbout 5km2-3kmShallower than 1 kmNatural geothermal reservoir (presence of steam and hot water)Hot spring resourcesInsufficient scientific understanding on relationship between hot springs and geothermal power generationDifficulties in identifying geothermal resources within very locally distributed natural cracksRelatively small-scale natural reservoirs in Japan (sustainable production capacity: 20–30 MW)Insufficient understanding of various phenomena that occur inside and outside a reservoirPossibility that there is a large amount of supercritical geothermal fluid in the cooling magmaInvisibility of the undergroundRisks of boreholes with low productivityMagma generated in the subduction　zone (supercritical conditions with　temperatures higher than 400–500℃ therein)