Challenges of TEPCO

  1. Energy & Resources


Hydro power generation

Hydro power is a purely domestic energy source for resource-scarce Japan and excels in both eco-friendliness and stability.

TEPCO owns 163 hydro power stations with a total output of approximately 8,980 MW. They are located in the Tonegawa River system mainly in Gunma and Tochigi Prefectures, the Shinanogawa River system running across Nagano and Niigata Prefectures, and the Sagamigawa and Fujigawa River systems in Yamanashi Prefecture.

Hydro power generation was once the mainstream power generation system in Japan. However, as demand for electricity soared with the nation's economic development, the primary type of power generation shifted from hydro power to thermal power by 1959.
Nevertheless, because of their favorable characteristic of being easy to start and shut down, hydro power plants today play the crucial role of adjusting output during peak demand hours.

Although large-scale plants have been dominant in hydro power generation, there is a recent trend toward effectively using even unused water resources. Hydro power generation for a maximum output of up to 1,000kW is particularly called "small hydro power generation."


TEPCO's small hydro power stations

TEPCO operates 19 hydro power stations with a maximum output up to 1,000 kW to utilize untapped energy sources (as of May 15,2012).

Prefectures with TEPCO's small hydro power stations (site in Tokyo is the Mikura Island)
List of TEPCO's small hydro power stations
Plant name Prefecture Maximum Output (kW) Number
Type River system River Commence-
ment of
Sawanagawa Tochigi 190 1 Waterway Nakagawa river Sawanagawa river 1925.10
Kurokawa Tochigi 920 1 Waterway Nakagawa river Kurokawa river, Yosasagawa river 1921.7
Syoubugahama Tochigi 450 1 Waterway Tonegawa river Jigokugawa river 1916.12
Togawa Tochigi 240 1 Dam Tonegawa river Togawa river 2011.1
Ayado Gunma 670 2 Waterway Tonegawa river Tonegawa river 1998.4
Nerigawa Gunma 1,000 1 Waterway Tonegawa river Nerigawa river, Akagisawagawa river 1920.12
Torao Gunma 270 1 Waterway Tonegawa river Kannagawa river 2011.11
Oshino Yamanashi 800 1 Waterway Sagamigawa river Sagamigawa river 1922.8
Tsuchimurogawa Yamanashi 350 1 Dam Sagamigawa river Tsuchimurogawa river 1999.12
Kamanashigawa Daisan Yamanashi 1,000 1 Waterway Fujigawa river Fujigawa river 1938.2
Tsugane Yamanashi 700 1 Waterway Fujigawa river Daimongawa river 1924.9
Ashigawa Daisan Yamanashi 530 1 Waterway Fujigawa river Ashigawa river 1912.1
Ashigawa Daini Yamanashi 380 1 Waterway Fujigawa river Ashigawa river 1906.7
Ashigawa Daiichi Yamanashi 470 1 Waterway Fujigawa river Ashigawa river 1900.8
Mikurajima Tokyo 50 1 Waterway Kawadagawa river Kawadagawa river 1957.9
Tonokuchizeki Daini Fukushima 850 1 Waterway Aganogawa river Kanayamakawa river 1919.6
Inekoki Nagano 510 1 Dam Shinanogawa river Azusagawa river 1999.4
Tochigawa Nagano 1,000 1 Waterway Shinanogawa river Nakatsugawa river, Tochigawa river 2010.12
Omachishinsegi Nagano 1,000 1 Waterway Shinanogawa river Kagogawa river 2012.5

Torao Hydro Power Station

Torao Hydro Power Station in Gunma Prefecture is a small hydroelectric power station with a maximum output of 270 kW that commenced operation on November 25, 2011.

It is TEPCO's first power station that uses a water bypass way. The plant effectively utilizes the head from the water bypass way for the Ueno Dam, which is the lower dam of our Kanagawa Pumped Storage Hydro Power Station.

To prevent river water from being stored in the reservoir more than necessary, the water bypass way is designed to bypass river water in the upstream of the reservoir and release it in the downstream of the dam. TEPCO has enabled the use of natural energy by building a small power station that takes advantage of the waterway's drop of about 101 meters.

Place Ueno-mura, Gunma prefecture
Maximum output 270kW
Effective head approx. 101 m
Maximum water use 0.35m3/s
Type of facility Waterway system

*Please see our press release for further information.