再生エネルギー研究センターパンフレット（英語）

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12Yanaizu-Nishiyama Geothermal Power Plant（Source：Tohoku Electric Power Co.,Inc.）Micro-earthquake data integration and visualization system(monitoring the behavior of the injected water)Status of installing the three-component seismometers　In order to prevent a decrease in steam production and to recover production, a water-recharge injection test has been conducted at the Yanaizu–Nishiyama Geothermal Power Plant in the Fukushima prefecture since FY2015. In this area, the geothermal energy team installed a precise micro-earthquake remote monitoring network using downhole three-component accelerometer for a geothermal well and other equipment, and operations were commenced. This enables the real-time monitoring of the microearthquake activities and advanced integrated analysis in FREA, and our plan is to contribute to the production recovery by proper water injection.Examination device of hot spring systemThe device simulates a pipeline of hot spring in the laboratory for the evaluation of hot spring monitoring sensors, the experiment of a hot spring power generator.Downhole three-component accelerometer for ageothermal wellIt is a downholetool that can detect extremely small earthquake motions occurring inside and outside the geothermal reservoir developed by AIST.Multiplexing sensing instrument for optical MEMS sensorThe team developed a device enabling the measurement of earthquake motion at many points with many optical MEMS sensors fabricated on an optical fiber.Main Research FacilitiesActivities and Achievements①Development of a simulator of water injection to a geothermal well　In some case, the capacity of a geothermal reservoir is improved by water injection to the reservoir through a geothermal well. The geothermal energy team collaborated with US and European researchers and developed a simulator for simulat-ing the response of a crack for water injection. As a result of conducting a demonstration test on a well with the reduced capacity in a geothermal field of the Tohoku region, the team achieved the capacity improvement as predicted from the prior simulation and succeeded in increasing the power generation (to about 1.1 MW).②Development of a remote and continuous monitoring system of a hot spring’s quality 　The team began to develop a system enabling the measurement of spring qualities of the hot springs’ temperature, flow rate, electric conductivity, etc., producing a prototype to scientifically explain the relationship between the geothermal power generation and the hot springs. This system enables stand-alone measurements and continuously transfers the obtained data to a server through the Internet. The performance evaluations by labora-tory experiments and field demonstration tests run for practical application at the end of FY2017.Simulation of a subsurface crackResult of a water injection testNumber of spinner revolutions (flow rate in a well) (rps)After water injectionBefore water injectionBefore water injectionDepth of excavation (m)Optical MEMS sensor