On 13/05/2010 23:23, Gib Bogle wrote:
Butbutbut... The tides are not simultaneous. They vary from place to
place
(Southampton has twice as many as most other places as well) This
should be
enough to reduce the peaks/troughs.

True, but the variation from north to south in Britain is only a few
hours (can't recall the exact number). The more salient point is that
not everywhere on the coast is a suitable turbine site. You need spots
where tidal currents are very high.

You need to put those nice people at:

http://easytide.ukho.gov.uk/EASYTIDE...electPort.aspx

right then.

I started to extract the figures below to counter TMH's claim that there
wasn't much range to our tides but here is as good a place as any to
post them together, with times. Today's figures used. Time is GMT and
range in metres.

Place Range time

East Coast

Leith 4.4 8.20
River Tees 4.1 9.44
Grimsby 5.1 11.54
Hunstanton 5.5 13.12
Lowestoft 1.7 15.35
Harwich 3.3 17.33
Southend 4.8 18.55

West Coast

Avonmouth 10.8 7.09
Aberdovey 4 8.11
Liverpool 7.4 11.02
Morecombe 7.5 11.25
Maryport 6.8 11.25

Times for the East Coast are for low water. Times for the West Coast are
for high water.

The grater the tidal range the greater the tidal flow or, in the case of
tidal barrages the greater the potential. Tidal barrages have the
potential to generate serious amounts of energy but the capital costs
are enormous. Machines to tap tidal flow are I suppose on a par with
wind turbines but should be cheaper to build and install as well as
being more predictable. (In case it still isn't apparent to Bruce I am
not a fan of windmills).