On Mon, 4 Feb 2013 16:37:00 -0800 (PST), "
wrote:

On Feb 4, 5:31*pm, wrote:
On Mon, 4 Feb 2013 13:24:04 -0800 (PST), "





wrote:
On Feb 4, 1:54*pm, wrote:
On Mon, 4 Feb 2013 10:41:50 -0800 (PST), "

wrote:
On Feb 4, 1:32*pm, wrote:
On Mon, 4 Feb 2013 08:57:50 -0800 (PST), "

wrote:
On Feb 4, 11:38 am, "Attila Iskander"
wrote:
"HeyBub" wrote in message

news:O96dnZQJY9B3JZLMnZ2dnUVZ_vCdnZ2d@earthlink. com...

Attila Iskander wrote:

And do they actually suck water from downstream to pump it back into
the dam ??

Yes. In California a few years ago, during one of their periods of energy
scarcity, several generating stations pumped water back into the resevoir
during off-peak hours (night). The California equivalent of a
perpetual-motion machine.

And where did they get the power to run those "pumps" ?

I would imagine it comes from some of the water flowing
through the generator, which would be the most logical source.

Ah, thermodynamics repealed!- Hide quoted text -

- Show quoted text -

No violation of thermodynamics involved.

It certainly is if you think you're doing this for a reason.- Hide quoted text -

- Show quoted text -

The reason is to have more water available to supply more
power during peak times during the day.

Don't be absurd. *If you're pumping water by using falling water,
there can be no gain.

You're not gaining energy. You're storing energy at night
by pumping water up to a reservoir above the power plant.
Then during the day, you're releasing the water, to get
the energy back.

You're losing energy.


If you're using falling water at night to pump
water during the day, where's the storage of that energy?

It's stored in the reservoir above the dam.

Then leave it there!

If I expend
energy to pump 100 gallons of water 500 ft higher, then
later I can run that water back down the 500ft drop
and into a generator, generating energy. If there were
no losses you'd get all the stored energy back. But
let's say it's only 75% efficient. In the example I gave,
it doesn't matter, because if the river is flowing at
100MW and the plant only has demand at night of 60MW,
then 40MW is going to waste. 40MW * 75% is
30MW of additonal power that the utility can sell in
the peak daytime.

You're nuts.



Let's say you have
100MW of generating capacity from water flow from the
normal flow of a river. * The generator could supply 130MW if
there were more water flow, but the river is only capable of
100MW. * *At night, the demand is only
60MW. *So, at night you take the extra 40MW that isn't needed
and use it to power pumps to move water to a reservoir
upstream of the generator. *The next day, when you need
more than *100MW, you start releasing that extra water,
boosting the generator output above 100MW.

Good grief. *Just store the water behind the dam and forget the whole
thing.

Yeah, if there is a suitable dam area to contain the additonal
water as part of the river ahead of the dam and IF you can throttle
back the river withoug screwing up
everything below it. You with Ralph on the idea of just turning
off the river at night? But none of that has anything to do with
your claim that the pumping system I described violates some
law of thermodynamics, does it?