YOKOHAMA, Japan, Oct 5, 2020 – (JCN Newswire) – Mitsubishi Power, a major subsidiary of Mitsubishi Heavy Industries (MHI) Group, has completed its renovation of the Otake Geothermal Power Station (Kokonoe-machi, Oita Prefecture) operated by Kyushu Electric Power Company. Commercial operation of the renovated facility began in October 2020. The stable electric power supply generated by the highly efficient and reliable steam turbine installed as part of this renovation project will curb CO2 emissions, and contribute to a decarbonized economy.
This renovation project was conducted under an engineering, procurement and construction (EPC) contract by a joint venture comprising Mitsubishi Power, which supplied the steam turbine, Mitsubishi Power Industries Co., Ltd., which handled the supply and installation of auxiliary equipment, and Mitsubishi Electric Corporation, which supplied the generator and electrical facilities.
The power generation system utilizes a “double flash and dual pressure” method, the first of its type in Japan. This allows for stable operation of the steam well and efficient use of geothermal resources, and has increased the power output by two megawatts (MW) compared to the previous facility, to 14.5MW. Construction was completed two months ahead of schedule from the plan when work began in May 2019, allowing for the start of commercial operation in October.
In the double flash and dual pressure method, high pressure primary steam from a powerful production well, and low-pressure secondary steam from a weak production well, are supplied to the steam turbine. Steam is further obtained by lowering the pressure of the hot water extracted from the primary steam, which is then used as secondary steam.
Geothermal energy utilizes the heat energy of the magma chamber inside the earth, and because no combustion takes place above ground, little CO2 is emitted into the atmosphere, making it an effective method of power generation for