On 25/09/14 08:07, Chris Hogg wrote:
On Wed, 24 Sep 2014 15:11:03 +0100, The Natural Philosopher
wrote:

On 24/09/14 11:03, Chris Hogg wrote:
On Tue, 23 Sep 2014 17:23:30 +0100, "harryagain"
wrote:

http://www.telegraph.co.uk/finance/n...kins-boss.html

They should really be looking at the whole Bristol Channel/estuary.

Massive environmental impact and enormous cost. A better alternative
surely are marine turbines. Less impact, less cost, and installable
over a large part of the estuary, as you suggest. But still no leccy
at slack water, the weakness of all tidal systems.
http://en.wikipedia.org/wiki/Tidal_power
http://en.wikipedia.org/wiki/Tidal_stream_generator


All tidal power is crap because the tides themselves are high entropy.
Ergo massive expensive structures causing huge eco impact to achieve
very little.


Once you look at entropy and energy density, assessing renewable energy
is simple.

And you always get the same answer. Its all crap.

Interesting comment, which I won't claim fully to understand, although
I have an inkling (thermodynamics was never my strong point!). Do you
have a link or book reference that gives a bit more detail, without
being too heavy or theoretical?



http://www.templar.co.uk/downloads/R...imitations.pdf

treats the energy density issue.

Entropy is really tied up in the efficiency curves.
I.e there is the same energy in a red hot poker as a bath of luke warm
water, but the red hot poker is a lot easier to get most of it out of.

It's lower entropy.

Mots renewable sources - wind and tidal and so on - are high entropy, so
you can only get out maybe 20-40% of what's in there to start with.

And low energy density as well. So you need BIG stuff to get it.



--
Everything you read in newspapers is absolutely true, except for the
rare story of which you happen to have first-hand knowledge. €“ Erwin Knoll