Scaling Protection Technology for Hachijyo-Jima Geothermal Power Plant

Abstract

Hachijyo-jima geothermal Power Plant, the first geothermal power plant to be built on a remote island in Japan, was constructed in the Nakanogo district of Hachijyo-Jima. Hachijyo-jima is an island located approximately 400km south of the Tokyo metropolitan area, and has a circumference of 58.9km and area of 65.9 km2. This island is gourd-shaped, and has two volcanic mountains, Miharayama (or Eastern Mountain, located in the south eastern part of the island) and Hachijyo Fuji (or Western Mountain, located in the northwestern part).
In 1989, the New Energy and Industrial Technology Development Organization (NEDO) selected the island as a site to survey for the promotion of geothermal development, and exploratory drilling confirmed the existence of promising geothermal resources in the southern part of the Eastern Mountain.
In 1992, the Tokyo Electric Power Company began geothermal development work on site and performed production well drilling, blow-off tests, an environmental survey, and the basic planning and design for a power generation plant. After having completed various pre-construction procedures, The Tokyo Electric Power Company stated construction of the Hachijyo-jima Geothermal Power Plant in June 1998. This plant was put into commercial operation on March 25,1999.