The Kazunogawa Pumped Storage Power Station is a pumped-storage hydroelectric power station near

Kōshū Kōshū or Koshu may refer to: * ** Kōshū, another name for Kai Province. ** Kōshū, Yamanashi, the present city in Yamanashi Prefecture. ** Koshu (grape) Koshu (甲州 ''kōshū'') is a white wine grape variety that has been grown primarily ...

in Yamanashi Prefecture, Japan. The station is designed to have an installed capacity of and three of the four generators are currently operational, for a total operational capacity of 1200 MW. Construction on the power station began in 1993 and the first generator was commissioned on 3 December 1999. The second was commissioned on 8 June 2000. The third one became operational on 9 June 2014, six year early due to post-power demand from the Great East Japan earthquake. The fourth and final generator is slated to be commissioned by 2024. It is owned by TEPCO and was constructed at a cost of US$2.2 billion.

Design and operation

The upper reservoir for the power station is created by the Kamihikawa Dam at which is a tall and long rock-fill embankment type. It has a fill volume of . The upper reservoir's capacity is of which is active (or "useful) for power generation. The lower reservoir is formed by the Kazunogawa Dam (葛野川ダム), which uses water from the Sagami River system. The Kazunogawa Dam is tall and long

roller-compacted concrete Roller-compacted concrete (RCC) or rolled concrete (rollcrete) is a special blend of concrete that has essentially the same ingredients as conventional concrete but in different ratios, and increasingly with partial substitution of fly ash for Po ...

gravity dam A gravity dam is a dam constructed from concrete or stone masonry and designed to hold back water by using only the weight of the material and its resistance against the foundation to oppose the horizontal pressure of water pushing against it. ...

. It has a structural volume of . The lower reservoir's capacity is of which is active (or "useful) for pumping into the upper reservoir. When energy demand is high, water from the upper reservoir is released down to the

underground power station An underground power station is a type of hydroelectric power station constructed by excavating the major components (e.g. machine hall, penstocks, and tailrace) from rock, rather than the more common surface-based construction methods. One or mor ...

via a single long headrace tunnel which splits into two tunnels before each separate into two long penstocks. Each penstock feeds a single reversible 400 MW

Francis turbine The Francis turbine is a type of water turbine. It is an inward-flow reaction turbine that combines radial and axial flow concepts. Francis turbines are the most common water turbine in use today, and can achieve over 95% efficiency. The proces ...

-generator with water before it is released into a long tailrace tunnel which discharges into the lower reservoir. When energy demand is low and therefore inexpensive, the turbines reverse into pumps and send water from the lower reservoir back to the upper reservoir. The process is repeated when necessary to help balance electricity loads. The difference in elevation between the upper and lower reservoirs affords an effective

hydraulic head Hydraulic head or piezometric head is a specific measurement of liquid pressure above a vertical datum., 410 pages. See pp. 43–44., 650 pages. See p. 22. It is usually measured as a liquid surface elevation, expressed in units of length, ...

of and maximum of .

References

{{Dams in Yamanashi Prefecture Dams completed in 1999 Energy infrastructure completed in 1999 Energy infrastructure completed in 2000 Energy infrastructure completed in 2014 Buildings and structures in Yamanashi Prefecture Pumped-storage hydroelectric power stations in Japan Underground power stations 1999 establishments in Japan

Design and operation

See also

References