Bruce wrote:
On Thu, 13 May 2010 17:22:44 +0100, Roger Chapman
wrote:
On 13/05/2010 16:42, Jim wrote:
On 13/05/2010 16:34, 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.
Southampton doesn't in fact have twice as many tides. After the first
high water, the tide recedes only slightly before a second high water
about 2 hours later.
From a power generation point of view it wouldn't be that different to
anywhere else.
I think you have missed the main point. As Bruce said tides follow a
predictable cycle but what he missed is that tides at different places
occur at different times. At any given time you can find tides round the
coast at every possible state from high to low and ebb and flow.
That's true. But it is the case that existing power stations are
distributed around the country to meet regional demand. There are not
huge transfers of power from one end of Britain to the other. The
National Grid is there to serve regions by connecting regional power
stations with their regional consumers.
With tidal power you can't easily do that, other than covering the
country with pylons to a far greater extent than exist today, and
transmission losses become significant.
There is also the issue that there are only a few sites where tidal
power will be viable, if indeed it is viable at all. The idea that
the entire coast would be suitable is fatuous in the extreme, because
long stretches of the coastline have very low (near zero) tidal
currents.
So that takes us back to pumped storage, as I said before.
which has similar drawbacks in that most demand is NOT at the bottom of
a 1000 foot damn holding back a lake the size of loch ness, so you STILL
need massive power cables connecting prime generators not just to
customers but ALSO to pumped storage, and you STILL need AS MUCH pumped
storage as generating capacity. So again, as with wind., you double up
the costs. Of generating AND transmission, half of which is idle at any
given time.
I wonder which is the next blind alley the discussion will take?
Photvoltaic, in which the whole sahara is covered with silicon panels
that survive dust storms and camel attack, whilst massive terawatt
cables snake under the mediterranean, untouched by Islamic terrorist
hands, to emerge into a neon lit Europe, thus solving all our energy
problems and a cost of only 50 times the gross national product, or 300
failed banks.