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" ?

  • $\begingroup$ why would the pumps be connected to the turbines? ... what would be the purpose of the turbines then? $\endgroup$
    – jsotola
    Feb 23 at 20:22
  • $\begingroup$ Why don’t you check out Dinorwig aka the water mountain before posting.? $\endgroup$
    – Solar Mike
    Feb 23 at 20:28
  • $\begingroup$ @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 $\endgroup$
    – jkztd
    Feb 23 at 20:50
  • $\begingroup$ @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. $\endgroup$
    – jkztd
    Feb 23 at 21:01
  • $\begingroup$ that makes no sense ... just shut off the water flow ... why waste water to pump some of it back $\endgroup$
    – jsotola
    Feb 23 at 21:49

1 Answer 1


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).


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge that you have read and understand our privacy policy and code of conduct.

Not the answer you're looking for? Browse other questions tagged or ask your own question.