Tohoku Electric Power increased capacity of the dammed hydroelectric Kamigo Power Plant in Asahi Town, Yamagata Prefecture, by 800kW from May 1, 2025.
According to a statement issued on the same day, the company raised the asset’s capacity from 15.4MW to 16.2MW without making any equipment upgrades. Instead, it increased the water flow to the turbine from 100m3 to 116m3 per second.
The project marks the second time for Tohoku EPCO to increase the capacity of an existing hydropower plant without replacing equipment. In February 2022, it boosted the capacity of its Daini Kanose Power Plant in Aga Town, Niigata Prefecture, by 2.2MW to 57.2MW. The increase led to about 3.1GWh in additional annual output.
Separately, the company has also been repowering its aging power plants to extend their useful life. Among other assets, it completed repowering the 2.6MW Miyanohara Power Plant in February 2025 and the 38.5MW Horai Power Plant in January 2025. While rated capacity stayed the same in both cases, expected annual generation was increased due to efficiency and reliability improvements.
Tohoku EPCO’s hydro portfolio included 203 power plants totaling 2.45GW as of May 1, 2025.
