Gas Turbines, Plant Optimization, Renewables

Mitsubishi companies contribute steam turbine, generator to Otake geothermal plant

Mitsubishi Power has completed its renovation of a geothermal power station in its native Japan.

The subsidiary of Mitsubishi Heavy Industries installed a new steam turbine as part of the renovation to reduce carbon emissions at the Otake Geothermal Power Station operated by Kyushu Electric Power Co.

Several Mitsubishi entities, including the Power and Electric subsidiaries, combined to form a joint venture for the engineering, procurement and construction (EPC) contact at the Otake plant. Mitsubishi Power supplied the team turbine, Mitsubishi Power Industries the auxiliary equipment and Mitsubishi Electric provided the generator and electrical facilities.

The power generation system utilizes a “double flash and dual pressure” method, the first of its type in Japan. 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.

The renovation increased power output by two MW to 14.5-MW capacity. Work began in May 2019 and was completed this month.

Kyushu Electric Power’s Otake Power Station began commercial operation in August 1967 as Japan’s first commercial geothermal power station. This plant is also Japan’s first wet steam geothermal plant, and Mitsubishi Power’s first commercial geothermal facility. Over more than fifty years in operation, this plant has contributed to a stable energy supply, and the decarbonization (sustainability) of society.

Mitsubishi Power split from its former joint venture with Hitachi in a break finalized earlier this year.