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Thursday, 8 March 2012

More Windmill woes ...

I see there is a bit of a kerfuffle going on in the "Green energy" lobby at present because the Chancellor and the PM won't give assurances they will continue to subsidise these hugely expensive follies.

I really must look it up, but there is a new technical paper published by Danish scientists and engineers who have identified a new problem with the "wind farms." Put simply, a windmill creates turbulence as it rotates, something we really all should be able to recognise. The big windmills create quite a bit. This is what catches birds out, and these really big blades create some interesting vortices as the wind moves past them and as they rotate - particularly at the tips. Any helicopter pilot or designer will tell you this is one of the more "interesting" features of flying one. Even when the blades are not rotating, they create some interesting turbulence "down wind" as the wind moves round, past or over them.

So why should this be a problem?

Ah, there lies the rub as they say. In a wind farm where you have several rows of these things, the first, upwind row, will operate efficiently. The row behind it loses around 10% of its efficiency and the row behind that, loses more ... Oh dear, so building the damned things in neat rows is not the most efficient way to arrange them. Apparently what you need is to have one long straight row of them. But hold on. The turbulence actually spreads out sideways as well ...

So, all those lovely windmills are probably not operating efficiently even when the wind is blowing within the very narrow operable range. Then, as I mentioned the other day in my post "Yesterday's Challenge" they're very likely generating power when its not needed or simply can't be distributed.

But those nice "Green Power" people don't mind, the government pays them for it anyway ... Or rather, you, the taxpayers, do!

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