Kasumi Yasukawa

Model study of the thermal storage system by FEHM code

The use of low-temperature geothermal resources is important from the viewpoint of global warming. In order to evaluate various underground projects that use low-temperature geothermal resources, we have estimated the parameters of a typical underground system using the two-well model. By changing the parameters of the system, six different heat extraction scenarios have been studied. One of these six scenarios is recommended because of its small energy loss.

Numerical modeling of a hydrothermal system around Waita volcano, Kyushu, Japan, based on resistivity and self-potential survey results

A self-potential survey has been conducted around Waita volcano, Kyushu, Japan. A large negative anomaly, generally interpreted as a surface recharge zone, has been observed at medium altitude. However, combined resistivity and self-potential modeling suggests that this anomaly is not necessarily related to surface recharge but to a high permeability column within the body of the volcano. This column encourages lateral flow, which results in a mixture of meteoric water and hot fluid flowing laterally towards the Takenoyu geothermal system. Such a combined modeling analysis has proved to be a useful technique for imaging subsurface fluid circulations.

Issues Around Geothermal Energy and Society in Japan

From 1967 geothermal power generation in Japan increased rather rapidly till 1999. The main players had been private sector supported by government’s subsidies. However various socio-economic reasons prevented private sectors from investing in new geothermal development in the 21st century. Legal frameworks and regulations kept geothermal power generation in Japan quite costly and opposition by local people involved in “hot-spring business” delayed geothermal projects. Then finally after the great east Japan earthquake and its following nuclear accident in 2011, the federal government renewed economic supports for geothermal development and modified some regulations which had been limiting geothermal development. Therefore, the currently remaining biggest barrier to geothermal development is social acceptance especially by local hot-spring business people. Although social study on this matter has just started recently and has not been applied to real system yet, experience from the past failure project enables us to consider possible solutions to apply to the society. Thus the federal government has begun supporting activities by developers or local governments for social acceptance.