The New Era of Geothermal Energy Utilization with Aid of Nuclear Reactor Technology

摘要

Japan has about 120 active volcanoes. Estimated potential of geothermal power generation is 23,470 MWe from hydrothermal reservoirs to a depth of 3 km. Geothermal energy is expected to be an important role for zero-carbon era. Currently, 21 electric power units at 18 geothermal sites are in operation with a total capacity of 537 MWe, which amounts to about 2.3% of its potential power. The main reason of such a low utilization rate is mainly due to its high cost and impact on ambient surrounding of power plant. We start to develop a new system of geothermal energy conversion. In order to do its first pilot experiment for the proposed system, case studies are carried out by using the two-fluid model which is well developed in the nuclear reactor field. The two types of extraction of hot water, that is, two-phase flow and single-phase liquid flow, have been examined. According to the results of case studies, the required material properties, dimension of test apparatus, experiment conditions, such as inlet pressure and flow rate, have been cleared.