Because there's more to the internet than hits alone, athol wrote:

Andrew wrote:
Again I doubt this, though I was surprised to see their working life
put at around 20 years. Of course the whole drive for these is highly
dependant of the renewable obligation payment levied on fossil fuels.

Thank you. You have reinforced my fundamental point. These devices
are _not_ environmentally positive. The energy required to make them
exceeds the "renewable" energy that they produce.

This sounds worryingly like axe-grinding to me. I can't see how, over
a twenty year lifespan, a wind generator won't produce more energy
than it takes to make the thing. Even at only one third usable output
time (two-thirds downtime due to lack of wind) that's over 60,000
hours of generation. If my maths is correct, a 1000kW generator
working at half power will output over 10^14 joules of energy in that
time - a little over a day's output from a nuclear powerstation. In
terms of the nation's energy consumption it's tiny; in terms of making
a hi-tech windmill I'd say it was huge.

And you have to define where you measure the start point of the energy
dept from. The amount of electricity used? The amount of coal burnt to
produce that electricity? The amount of coal + its extraction and
transport energy? Don't forget that coal fired power stations (50% of
electricity production in the UK) are hugely inefficient in terms of
converting fuel into electricity. Seems to me that there is plenty of
scope for an advocate either way to spin the figures up.

I don't relish the prospect of wind turbines marching across the
countryside, but I won't easily buy the notion that they produce less
energy that it takes to make the damn things.


--

Stewart Hargrave

I run on beans - laser beans


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