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Asahi Kasei to renovate a hydroelectric power plant in the Nobeoka area

August 31, 2021
Asahi Kasei Corp.

Asahi Kasei has decided to implement a large-scale renovation of the Suigasaki Hydroelectric Plant, completed in 1950 with a capacity of 18,000 kW, in Takachiho-cho, Nishiusuki-gun, Miyazaki Prefecture, Japan.

  • The Suigasaki Hydroelectric Plant
    The Suigasaki Hydroelectric Plant

1. Background

The Asahi Kasei Group operates business in harmony with the environment and local communities based on a Group Vision of providing new value to society by enabling “living in health and comfort” and “harmony with the natural environment.”

Ever since our founding, we have supplied our business operations in the Nobeoka area with power from hydroelectric plants on the Gokase River system. We now have 9 hydroelectric power plants with a maximum total output of 56,380 kW. Although some of the hydroelectric plants are more than 90 years old, we have continued safe operation by systematic maintenance. Ultimately, however, it was determined that successive large-scale renovations of the hydroelectric plants would be required, beginning with the November 2018 decision to implement a large-scale renovation of the Gokasegawa Hydroelectric Plant, which was completed in 1925 with a capacity of 13,500 kW, followed by the August 2019 decision to implement a large-scale renovation of the Mamihara Hydroelectric Plant, which was completed in 1926 with a capacity of 5,000 kW.

The decision to implement a large-scale renovation of the Suigasaki Hydroelectric Plant is part of this plan to enhance the reliability of our hydroelectric plants and secure a stable supply of clean energy over the long term in accordance with our management strategy prioritizing sustainability.

2. Overview of the Suigasaki Hydroelectric Plant

Location Takachiho-cho, Nishiusuki-gun, Miyazaki Prefecture, Japan
Water system Gokase River
Plant type Run-of-river
Maximum water flow 27.16 m3/sec

Main renovations: Replacement of turbines and generators, partial renewal of water channel

  Current After renovation (planned)
Licensed output 18,000 kW 19,000 kW

The large-scale renovation of the Suigasaki Hydroelectric Plant will enhance the efficiency of the hydraulic turbines and generators, resulting in an annual reduction in CO2 emissions of approximately 10,000 tons as we aim to further reduce the environmental burden of our operations.

Renovation work is scheduled to begin in October 2022 and the rebuilt plant is scheduled to begin operation in April 2025. Work will be performed with due consideration for nearby residents and the surrounding environment.

3. Moving forward

Asahi Kasei operates 9 hydroelectric power plants and 4 thermal power plants which provide in-house supply of around 90% of the power used by our operations in the region of Nobeoka and Hyuga. To further increase the ratio of clean energy in addition to the hydroelectric plants, in 2012 we began power generation using biomass fuel and in September 2020 we began work to convert our 3rd coal-fired thermal power plant, completed in 1971 with a capacity of 34,000 kW, into an LNG-fired thermal power plant of equivalent capacity.

Asahi Kasei continues to further advance successive measures to utilize clean energy as part of an ongoing effort to proactively contribute to a society of clean environmental energy through our environmentally-friendly business operations.