Review of the HDR Development at Hijiori Site, Japan

Hijiori HDR (Hot Dry Rock) project was one of the famous HDR development programs. NEDO (New Energy and Industrial Technology Development Organization) carried on this domestic HDR project from 1985 to 2002. Much new knowledge were found in Hijiori project and contributed to the progress of the international HDR development. Although Hijiori project successfully reached to the final long-term circulation test, conducted from 2000 to 2002, development of HDR in Japan stops for the time being not because of technical reasons but political ones. A review program was started just after the final experiment at Hijiori site to summarize and to discuss the potential of Hijiori project for the future. A review committee was organized and discussions were started. At the start of our discussions, recognition of the current HDR concept was the main theme. On the next step, which has a technical theme, five subgroups, overall system design, field characterization, reservoir creation, circulation/heat extraction and monitoring, were set up and discussions were continued both in the subgroups and in the whole committee. A brief history of the Hijiori project, an outline of the review and several interesting topics discussed in the review will be presented in this paper.