The Okuyoshino Pumped Storage Power Station (奥吉野発電所) is located 15 kilometres (9.3 mi) north of Totsukawa in Nara Prefecture, Japan.

[3][4][5] During periods of low demand when electricity is cheap, the power station pumps water from the lower reservoir to the upper.

When energy demand is high, the water is released back down to the power station through the same tunnels to generate electricity.

Additionally, the six 201 megawatts (270,000 hp) Francis pump-turbine-generators are reversible and serve to both pump water and generate electricity.

The tunnel can divert a maximum of 140 cubic metres per second (4,900 cu ft/s) of water and discharges downstream of the Seto Dam.