Geothermal Binary Power Generation System

Abstract

In utilization of geothermal resources in Japan, high temperature geothermal resources have been used for power generation but intermediate and low temperature geothermal resources which are widely distributed in Japan are mostly left unused, only a part of which is directly used for some purporses such as bath and heating. In consideration of such a situation, New Energy and Industrial Technology Development Organization in Japan (NEDO) started a project to generate electric power by utilizing the low level geothermal resources with a binary power generating system and the function of Mitsubishi Heavy Industries was to engineer, manufacture, and supply all major equipment for power generation. The results of the project were verified with a 500 kw class pilot plant which was built in Takigami in Oita Prefecture in February 1997 and operated for one year. In Takigami area, there is one 25 MW geothermal power plant, which is owned operated by Kyusyu Electric Power Corporation. And there are many production and injection wells for the 25MW power generation. The binary power plant utilized the hot water from the separater which had been injected. This paper introduces the system, specification of main equipment and operating results of the pilot plant.