Windfarms: One of the great deceptions of our time

I long had no particular views on wind farms one way or the other. But six years ago, when I first seriously looked at what they actually contribute to our energy needs and our environment, I had a profound shock. It was clear that the craze for wind energy had become one of the greatest self-deceptions of our time.

Far from being "free", wind is one of the most expensive ways of generating electricity yet devised. Without an almost 100 per cent subsidy, unwittingly paid by all of us through our electricity bills, no one would dream of building giant wind turbines in Britain, because their cost is not remotely competitive.

Turbines are hopelessly ineffectual. The amount of electricity they deliver is derisory. The total power generated by all the 2,300 turbines so far built in Britain - covering hundreds of square miles of countryside and sea - averages just over 600 megawatts in a year, less than that contributed by a single medium-size conventional power station.

Most serious of all, however, is the fact that wind energy is hopelessly unreliable, for the simple reason that wind speeds are not only constantly changing but wholly unpredictable. One minute a turbine may be whizzing round, generating at full capacity; the next the wind drops and the turbine is contributing only a fraction of its capacity or nothing at all.

To keep electricity supplies going, the grid must have permanently available alternative conventional power sources equivalent to the maximum capacity of the wind turbines, ready to step in when the wind stops. This in itself is hugely inefficient, adding greatly to costs and, as they have discovered on the Continent, threatening to destabilise the grid or bring it to a halt when wind speeds change dramatically.

The best-kept secret of the wind industry, however, which continues to fool both politicians and the media, is its trick of referring only to the contribution of windmills in terms of their "installed capacity", as if that is what they will actually deliver. They talk about a "16 megawatt" wind farm "powering x thousand homes" as if that is the contribution it will make to our electricity needs. Yet in reality, thanks to the intermittency of the wind, a turbine will on average produce through the year only a quarter of its capacity.

The success of this deception means that politicians almost invariably exaggerate the potential benefits of wind power by a factor of four. And of course the other great trick is to conceal the fact that all this must be paid for by that huge hidden subsidy.

The real danger of the "great wind scam" is that it takes the eyes of politicians off the real energy crisis fast approaching us, so that we are not building the proper power stations we need to keep our lights on. That is why it will one day be looked back on as having been one of the most incomprehensible blunders of our age.