Pumped-storage hydroelectricity: Difference between revisions

The largest one, Saurdal, which is part of the [[Ulla-Førre]] complex, has four 160 MW [[Francis turbine]]s, but only two are reversible. The lower reservoir is at a higher elevation than the station itself, and thus the water pumped up can only be used once before it has to flow to the next station, Kvilldal, further down the tunnel system. And in addition to the lower reservoir, it will receive water that can be pumped up from 23 river/stream and small reservoir intakes. Some of which will have already gone through a smaller power station on its way.

 

Conventional hydroelectric dams may also make use of pumped storage in a hybrid system that both generates power from water naturally flowing into the reservoir as well as storing water pumped back to the reservoir from below the dam. The [[Grand Coulee Dam]] in the United States was expanded with a pump-back system in 1973.<ref>{{Cite book |title=Alternative Energy and Shale Gas Encyclopedia |publisher=Wiley |year=2016 |isbn=978-0470894415 |editor-last=Lehr |editor-first=Jay H. |edition=1st |page=424 |editor-last2=Keeley |editor-first2=Jack}}</ref> Existing dams may be repowered with reversing turbines thereby extending the length of time the plant can operate at capacity. Optionally a pump back powerhouse such as the [[Richard B. Russell Dam|Russell Dam]] (1992) may be added to a dam for increased generating capacity. Making use of an existing dam's upper reservoir and transmission system can expedite projects and reduce costs.