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Regarding pumped storage hydropower,

In the case of some high altitude upper reservoir that feeds several turbines located at the bottom of a valley, where there's a lower reservoir too.

Assuming in this case turbines are not reversible by design, and cannot act like pumps, and therefore separate dedicated pumps are required to pump up water to the upper reservoir.

Should those pumps be fed electrically? Or should those pumps be directly linked to turbines using some clutch? How does efficiency of "converting hydraulic to electrical and back to hydraulic" compare to only "convert hydraulic to hydraulic" ?

  • why would the pumps be connected to the turbines? ... what would be the purpose of the turbines then? – jsotola Feb 23 '23 at 20:22
  • Why don’t you check out Dinorwig aka the water mountain before posting.? – Solar Mike Feb 23 '23 at 20:28
  • @SolarMike I don't know about Dinorwig and very little about hydropower in general, hence the question. thanks btw I'm reading about it and will remove this post if it answers my question –  Feb 23 '23 at 20:50
  • @jsotola pumps would be connected to turbines' shaft to pump water back up in upper reservoir. Purpose of the turbine is to power an electric generator, and in this case to allow to switch from powering a generator to powering a pump, when required. –  Feb 23 '23 at 21:01
  • that makes no sense ... just shut off the water flow ... why waste water to pump some of it back – jsotola Feb 23 '23 at 21:49

1 Answers1

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Yes, electrically.

The normal purpose of these systems is to provide peak power generation capacity. Peak power often has to be generated via expensive fossil fuel systems. Peak power demand is often the late afternoon due to heat loads and people returning home at the end of the work day, plus additional line losses (I-squared-R losses) due to high power draw. These systems can provide peak generating capacity by drawing down the water level in the upper reservoir.

The water is pumped back up when electrical demand is low (like at 3 am) and lower cost power can be used (such as a base-loaded nuclear plant).

Tiger Guy
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