On Wed, 11 Sep 2013 10:54:00 -0700 (PDT),
wrote:

Just to put some figures on that, if you could get 100% efficiency and
assuming you had say a 100 metre height difference, you need 3.6 tonnes
of water per kWh.

http://www.reuk.co.uk/Calculation-of-Hydro-Power.htm

100 m head, 1.7 l/s gives 1 kW electrical output @ 60% effciency.

1.7 l/s is 1.7 * 60 * 60 = 6120 l/Hr or 6.12 tonnes or cu m per hour.

Plans have just been approved for a new pumped storage scheme in
North Wales:

http://www.bbc.co.uk/news/uk-wales-n...wales-23920312

After much digging it's proposed to be just under 50 MW. So tiddly
widdly.


--
Cheers
Dave.