'Wind turbines are a poor way to harness energy - but a very good way to generate public subsidies' says Andrew Gilligan.

The most important piece that I read this weekend was Andrew Gilligan's piece on Wind Farms in The Telegraph. You must read the whole article so as to have the facts to hand the next time you meet someone who thinks that wind power is the saviour of the UK. Here is one long extract that I thought most interesting:

'RUK (Renewables UK) says that “every unit of electricity from a wind turbine displaces one from conventional power stations”, and even the existing wind turbines have “the capacity to prevent the emission of 3.7 million tonnes of carbon dioxide per annum”.

The key weasel word in that last sentence is “capacity”. The CO2 reduction figure assumes that all wind turbines are able to generate electricity to 100 per cent of their capacity, 100 per cent of the time. But the basic problem with wind power is that most of the time, the wind does not blow.

A typical commercial turbine needs a wind speed of between 6-10mph to start operating – and automatically stops when the wind is more than around 55mph, to protect its mechanisms. Even when the wind is blowing between those speeds, it – and therefore the amount of electricity generated – is variable, and usually below the turbine’s full theoretical capacity.

According to government figures, the average wind turbine operates to just 27 per cent of its capacity – even the industry only claims 30 per cent – and there are some grounds for suggesting that even this is a significant exaggeration. Professor Michael Jefferson, of the London Metropolitan Business School, says that in 2008 less than a fifth of onshore wind farms achieved 30 per cent capacity.

One analysis of the government figures, albeit commissioned by wind farm opponents, suggested that Britain’s biggest wind farm – the 140-turbine installation at Whitelee, near East Kilbride – operated to just 7.3 per cent of its capacity that year.

That might be all right if we could store electricity for when it is needed – but we can’t, at least not in large quantities. The power companies have to generate it at exactly the moment you want to use it.

Unfortunately, the wind might not be blowing when millions of people want to put the kettle on after Coronation Street ends. If it only starts blowing when everyone has turned off the lights and gone to bed, that is of very little use.

Jeremy Nicholson, director of the Energy Intensive Users’ Group, which represents heavy industrial users of electricity, says: “Wind is a particularly useless form of power if you don’t have a way of storing the energy. It just seems the politicians have been taken in by the wind lobby, and they’ve taken leave of their senses.”

The wind industry argues that the wind is always blowing somewhere in the UK or off its shores, so provided the wind farms are widely enough spread, it should not matter.

But Professor David MacKay, who is now chief scientific adviser at the Department of Energy and Climate Change, has pointed out that in autumn/winter 2006/7 there were 17 days when output from Britain’s wind turbines was less than 10 per cent of their total capacity. On five of those days, output was below 5 per cent and on one day it was only 2 per cent. And those were the windier seasons.

To cope with what’s called “intermittency”, you must do two things.

First, you have to build far more wind turbines, in far more places, than you theoretically need. Prof MacKay says: “We need to be imagining industrialising really large tranches of the countryside.” Every view, from every summit in Britain – apart, perhaps, from a handful of specially preserved recreational mountains – will be like the view from Plynlimon.

The wind turbines required in Britain alone, says Prof MacKay, would amount to about double the number of all turbines in the world. Even then, “the maximum plausible production from on-shore windmills is 20 kilowatt hours per day per person”, about a sixth of Britain’s actual consumption.

Offshore offers further potential, but is much more expensive – meaning it will never provide more than a minority of wind generation in Britain. It also requires huge and ugly infrastructure, such as new harbours and power lines, on land.

The second thing you have to do is build more conventional, carbon-emitting power stations. Unlike wind farms, these can provide electricity predictably and more or less on demand.

Campbell Dunford, director of the Renewable Energy Foundation (REF), says that Germany – which has the largest number of wind turbines in Europe – “is building five new coal power stations, which it does not otherwise need, purely to provide covering power for the fluctuations from their wind farms. I am not sure [wind] has been a great success for them.” Mr Dunford claims that Germany’s CO2 emissions have actually risen since it increased its use of wind power. Though the wind itself might, in RUK’s words, be “free,” the cost of backup capacity is likely to be astronomical.

The figures are fluid, and fiercely disputed by the industry, but the House of Lords’ economic affairs committee estimated that wind was at least 50 per cent more expensive per unit generated than the other main non-CO2 option, nuclear. '

I have blogged before about the problem about relying on wind power for electricity generation but the facts just seem to go on being ignored by the politicians and environmentalists. I always blamed this on ignorance and/or blinkered dogma, but now I wonder if it might also be at least partly due to money. REad the end of Andrew Gilligan's article for more about the money to be made from wind power. Then have a think about who Nick Clegg's wife now works for and Chris Huhne's seeming obsession with wind power...