Tanbara Dam (玉原ダム, which can be mistakenly read Tamahara Dam
[) is a 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 ...
impounding the headwaters of the Hotchi River, a Tone River
The is a river in the Kantō region of Japan. It is in length (the second longest in Japan after the Shinano River) and has a drainage area of (the largest in Japan). It is nicknamed Bandō Tarō (); ''Bandō'' is an obsolete alias of the ...
tributary in Gunma Prefecture
is a landlocked Prefectures of Japan, prefecture of Japan located in the Kantō region of Honshu. Gunma Prefecture has a population of 1,937,626 (1 October 2019) and has a geographic area of . Gunma Prefecture borders Niigata Prefecture and Fuk ...
of Japan
Japan is an island country in East Asia. Located in the Pacific Ocean off the northeast coast of the Asia, Asian mainland, it is bordered on the west by the Sea of Japan and extends from the Sea of Okhotsk in the north to the East China Sea ...
. It is located north of Numata. It creates the upper reservoir for the Tamahara Pumped Storage Power Station (玉原発電所). Construction began in 1973 and the dam was complete in 1981 while the power station was commissioned in 1986. It is tall and withholds a reservoir with a storage capacity of . Of that capacity, is active (or useful) for power generation. The lower reservoir for the pumped-storage
Pumped-storage hydroelectricity (PSH), or pumped hydroelectric energy storage (PHES), is a type of hydroelectric energy storage used by electric power systems for load balancing.
A PSH system stores energy in the form of gravitational potent ...
power station is created by the Fujiwara Dam
is a gravity dam on the Tone River in Gunma Prefecture of Japan. It is located north of Minakami. It was constructed between 1951 and 1957. The dam itself supports a single Francis turbine hydroelectric generator with a 23 MW capacity which was ...
, located to the northwest on another Tone River tributary. Power is generated during periods of high energy demand and pumping occurs during times when energy demand is low such as at night. The power station contains 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 pro ...
pump-generators which serve to both pump water and generate electricity. The upper Tamahara Reservoir is at an elevation of and the lower Fujiwara Reservoir is at which affords the power station an effective hydraulic head of . When pumping, the pump-generators can move up to of water and when generating, they discharge up to .
See also
*List of power stations in Japan
A list is a set of discrete items of information collected and set forth in some format for utility, entertainment, or other purposes. A list may be memorialized in any number of ways, including existing only in the mind of the list-maker, but ...
*List of pumped-storage hydroelectric power stations
The following page lists all pumped-storage hydroelectric power stations that are larger than in installed generating capacity, which are currently operational or under construction. Those power stations that are smaller than , and those that are ...
References
{{Dams in Gunma Prefecture
Dams completed in 1981
Dams in Gunma Prefecture
Rock-filled dams
Pumped-storage hydroelectric power stations in Japan