Japan ranks 8th in hydroelectric generation, with a 50 gigawatt capacity generating 8 per cent of total power generation in 2022. This piece will focus on the Japanese government’s ambition and strategy regarding hydropower. I will talk about prominent companies within the hydropower industry and the challenges faced by the sector.


The Japanese government 2021 set a target to attain 36 to 38 per cent of its electricity generation from renewable energy sources by 2030, up from 20.3 per cent in 2021, out of which 11 per cent will be from hydropower from 7.5 per cent in 2021. Through the above strategy, it will be able to reduce its carbon emissions by 46 per cent by 2030. Moreover, it intends to become a carbon-neutral nation by 2050.

Biggest Hydropower plants:

  • Kannagawa pumped hydro storage plant is on the Minamiaiki River in Nagano, owned and developed by Tokyo Electric Power Co Holdings. Construction commenced in 1997, and the project was completed in 2005, boasting a total capacity of 2820 megawatts.
  • Okutataragi pumped hydro storage plant is on the Ichikawa River Basin in Hyogo and is under Kansai Electric Power. It was developed in a single phase and commissioned in 1974 with a total capacity of 1932 Megawatt.
  • Okukiyotsu pumped hydro storage plant is on the Tashiro River in Niigata, owned and developed by Electric Power Development. Construction commenced in 1972, and the project was commissioned in 1978, achieving a total capacity of 1600 megawatts.
  • Okawachi pumped hydro storage plant is on the Inumi River in Hyogo, owned by Kansai Electric Power. Construction began in 1980, and the project reached completion in 1992, featuring a total capacity of 1280 megawatts.
  • Shintakasegawa pumped hydro storage plant is on the Takese River in Nagano, owned by Tokyo Electric Power Co Holdings. It was developed in a single phase and commissioned in 1979 with a total capacity of 1280 Megawatt.

Top Operators:

  • Hitachi Mitsubishi Hydro Corporation, based in Tokyo, was founded in 2011. A collaboration between Hitachi and Mitsubishi, this joint venture provides services encompassing marketing, engineering, installation, construction, and maintenance of hydropower generation systems.
  • Renewable Japan Co., Ltd, headquartered in Tokyo, was established in 2012. It is engaged in developing, operating and managing power stations employing solar, wind and hydropower.
  • J-Power Group has a head office in Tokyo, created in 1952. It is an electric utility producing electricity from coal and hydropower stations.
  • Toshiba Corporation, the main office in Tokyo, was set up in 1939. The company manufactures hydroelectric generation equipment for electric utilities, including hydraulic turbines and generators.
  • JAG Energy Co Ltd, based in Tokyo, began in 2006. It is involved in power generation across solar, wind, hydro and biomass.


  • The biggest challenge is that building large hydropower plants harms the ecology. For example, they have the potential to alter river temperatures and water quality, as well as obstruct the flow of nutrient-rich sediment.
  • The second issue is that most easily exploitable rivers have already been exhausted, and finding new locations with the necessary water resources and environmental considerations is difficult.
  • The third issue is water insecurity in certain regions, as hydropower plants necessitate a dependable and ample water supply. Balancing the needs of agriculture, industry, and hydropower can be challenging, especially during drought.


Japan, ranking 8th globally in hydroelectric generation, harnesses 50 gigawatts, constituting 8% of its total power generation in 2022. Focusing on the government’s ambition, Japan aims to attain 36-38% of electricity generation from renewables by 2030, with hydropower accounting for 11% of this target. This strategy targets a 46% reduction in carbon emissions by 2030, aligning with Japan’s goal to become carbon-neutral by 2050.

The top hydropower plants, like the Kannagawa and Okutataragi, showcase Japan’s prowess. Leading operators, including Hitachi Mitsubishi Hydro and J-Power Group, contribute significantly. However, challenges persist, such as ecological impacts from large plant construction, the scarcity of viable river locations, and water supply uncertainties, highlighting the delicate balance needed for sustainable hydropower growth. Japan’s journey towards an eco-friendly energy landscape remains both ambitious and complex.

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