On 12/19/2013 1:56 PM, Frank wrote:
....

I've heard of water being pumped back up hill for energy storage. Of
course that energy was probably from another source that could not
conserve it or cost more to throttle back.

Yes, even hydro isn't 100%. There's no benefit in trying to generate
the power for your own pumped storage; it loses.

There are pumped storage peaking units which use off-peak generation for
the purpose to be able to provide peak capacity later. Smith Mountain
Dam hydro unit in VA was built for the purpose; I've not looked to see
whether they're still using it that way or not since have been gone 30
yr or so now...

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