Update, May 2005: While it’s true that WindSave appear to have made their device obey the laws of physics (at least according to their published spec), I’m keeping this posting intact.
If the data on their website are to be believed, WindSave cannot generate the figures they claim. There’s much geeky theory involved, but basically, they’re claiming efficiencies that cannot be attained.
In short, they are claiming coefficients of performance of 0.724 and 0.887 for their turbines. Unfortunately, the theoretical maximum efficiency for a wind turbine — the Betz limit — is 0.593. So something, somewhere, is screwy. I’m pretty sure it’s not my sums, as they’ve been verified by an external source.
I worry that the UK energy minister, Brian Wilson, has been taken in by this. Five minutes with a calculator and a wind energy primer shows that these things are too good to be true.