Brian Sharrock wrote:
"David Hansen" wrote in message
...
On Thu, 13 Jul 2006 17:24:33 +0100 someone who may be Andy Hall
wrote this:-

Nobody is suggesting generating 50% of electricity from wind farms.
At present prices the costs would be very high.


Which is really why it's not worth bothering.....

It is certainly worth bothering to get the percentage to the current
economic limit of 20%. Generation that is relatively cheap to build
and decommission and which has zero fuel cost is something to use
whenever possible.


--
David Hansen, Edinburgh


You're conveniently leaving out of your claim the _input_ energy costs of
producing the structures. No structure, consisting of a concrete base(?),
pilings, mast, ginormous blades, turning gear, generators, control systems,
synchronising apparatus, cables etc. etc. can realistically claim to have
'zero fuel cost'. The 'cheap to build' claim needs to be substantiated with
a 'how much energy needs to be put _in_?'; versus 'how much energy may be
extracted?' Just basing a claim on 'what cost have the beancounters
attributed to this scheme?' , isn't ,IMHO, a valid baseline to draw any
conclusions.
Pounds sterling shouldn't be the base-line but Megajoules in/Megajoules out.

Your prejudices may vary

This is a common view, and imho a mistaken one. Real world energy input
is reflected better by cost than it is by looking at energies used
directly in the manufacture. Why?
1. Business activities other than manufacture come into it IRL, and
often their energy inputs overwhelm manufacture energy use.
2. For every tool or material used in manufacture, it has had to be
manufactured or harvested. For every material or tool used to do that,
those also had to be manufactured. And so on indefinitely.


NT