The Shin-Takasegawa Pumped Storage Station (新高瀬川発電所) uses the Takase River (a tributary of the

Shinano River The , known as the in its upper reaches, is the longest and widest river in Japan and the third largest by basin area (behind the Tone River and Ishikari River). It is located in northeastern Honshu, rising in the Japanese Alps and flowing g ...

) to operate a

pumped storage Pumping may refer to: * The operation of a pump, for moving a liquid from one location to another **The use of a breast pump for extraction of milk * Pumping (audio), a creative misuse of dynamic range compression * Pumping (computer systems), the ...

hydroelectric scheme about west of Ōmachi in

Nagano Prefecture is a landlocked prefecture of Japan located in the Chūbu region of Honshū. Nagano Prefecture has a population of 2,052,493 () and has a geographic area of . Nagano Prefecture borders Niigata Prefecture to the north, Gunma Prefecture to the ...

, Japan. Part of the system is within

Chūbu-Sangaku National Park is a national park in the Chūbu region of Japan. It was established around the Hida Mountains and encompasses parts of Nagano, Gifu, Toyama and Niigata prefectures. It was designated a national park on December 4, 1934, along with Daisetsuza ...

. Construction on the complex began in 1971, concluded in 1978 and the power station was commissioned in 1980. The power plant has a installed capacity and its upper reservoir is created by the Takase Dam, a rock-fill dam — which at in height is the tallest of its type in Japan. It is also the second tallest dam in Japan, next to

Kurobe Dam The or , is a high variable-radius arch dam on the Kurobe River in Toyama Prefecture, Japan. The tallest dam in Japan, it supports the 335 MW Kurobe No. 4 Hydropower Plant and is owned by Kansai Electric Power Company. It was constructed betwee ...

Design and operation

When energy demand is low and therefore electricity less expensive, the turbines reverse and pump water from the lower reservoir back into the upper reservoir. This process repeats depending upon energy demand and water availability. Water released from the lower reservoir is used to power the Nakanosawa Power Station which uses of

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, ...

to power a single Francis turbine generator. It was commissioned in May 1980.

Takase Dam

Creating the upper reservoir is the Takase Dam which is a tall and long rock-fill

embankment dam An embankment dam is a large artificial dam. It is typically created by the placement and compaction of a complex semi-plastic mound of various compositions of soil or rock. It has a semi-pervious waterproof natural covering for its surface and ...

with a structural volume of . The Takase Reservoir has a capacity of which only is active (or "useful") for power generation. The low active capacity of the reservoir is due to the high levels of silt in the Takase River which cause the reservoir to reserve 79 percent of its capacity for this purpose. During operation, the upper reservoir only draws down . During periods of high energy demand, water from the Takase Reservoir is released down to the power station. After received by the intake, water initially travels along two diameter and long head-race tunnels. At the terminus of these tunnels, they split into four long

penstock A penstock is a sluice or gate or intake structure that controls water flow, or an enclosed pipe that delivers water to hydro turbines and sewerage systems. The term is inherited from the earlier technology of mill ponds and watermills. H ...

s which drop down a deep shaft 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 ...

. At the power station, the water operates four reversible

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 ...

-generators before being discharged into the lower reservoir, created by the Nanakura Dam.

Nanakura Dam

The Nanakura Dam is a tall and long rock-fill

with a structural volume of . The reservoir created by the dam, the lower reservoir, has a capacity of which is active. To protect in against rapid draw-down in water levels (as much as ), the top of the dam is coated in hard rock materials.

References

External links

Shin-Takasegawa Power Station
at TEPCO {{Authority control Dams in Nagano Prefecture Pumped-storage hydroelectric power stations in Japan Ōmachi, Nagano Chūbu-Sangaku National Park Energy infrastructure completed in 1980 Underground power stations

Design and operation

Takase Dam

Nanakura Dam

See also

References

External links