Abstract
Technologies to develop the Hot Dry Rock (HDR) geothermal energy was reviewed. Since 1985, the New Energy and Industrial Technology Development Organization (NEDO) has promoted HDR project at Hijiori with the technical support from National Institute for Resources and Environment (NIRE) under New Sunshine Program. The objective of this project is to develop and confirm technologies which are required for the development of HDR. In 1991, a heat extraction test was successfully conducted with a 1, 800 m deep reservoir for three month using one injection well (SKG-2) and three production wells (HDR-1, HDR-2 and HDR-3). Water recovery during the test was about 80 % and the thermal output of the produced water and steam was about 8 MW. Deep reservoir with the depth of 2, 200 m has been developed for future heat extraction test for about two years.
