Orderer Tokyo Electric Power Company Holdings, Incorporated
Completion 2005
Structure and scale Headrace tunnel (NATM, minimum ventilation, rubber-tired system tunneling method): excavation cross-section: 79m², tunnel length 2,421m; headrace lower opening service tunnel: excavation cross-section: 28m², tunnel length: 360m; pressure-control tank: vertical shaft depth: 101.4m, finishing diameter: φ17m; connection road: light area: 821.5m, tunnel part: 678m; excavated soil treatment site: embankment volume: 564,000m³; concrete manufacturing and supply:
shipping volume: 141,000m³
Location Gunma Prefecture
Application Hydroelectric power station (water pumping type)

The Kannagawa Hydropower Plant is a large-scale pure water pumping-type power station that spans across Nagano Prefecture and Gunma Prefecture. Every second, 510t of water flows through a headrace tunnel with an effective head of 653m, and the plant boasts an output of 470 thousand kW per unit.