When the wind doesn't blow

Wind power the answer to our Country's need for green power, so say the Labour government and they have experts to advise them, right? Well no, despite the government unveiling a £100 billion plan to build at least 4,000 wind turbines on land, with a further 3,000 offshore; there are major problems. The online journal, Energy Policy, has a report written by an independent consultancy and funded by the Renewable Energy Foundation, the report says backup electricity plants will be needed to meet demand during calm conditions. But the UK is so windy, this cannot be true... The report finds that the wind around Britain is too volatile to provide reliable energy. In fact, using wind data from the Met Office, researchers found that in January, when energy demand is highest, wind farms often fail to produce enough electricity, dropping on occasion to 4 per cent of their maximum output (remember that figure it will be important). As the shortfalls in power would be unpredictable any backup fossil fuel plants would need to be switched on and off to make up the shortfall in supplies and this is a highly inefficient process that would reduce any carbon savings from wind farms. The report's authors used data on wind speeds and electricity demand from the past six years to work out what impact 25 Gigawatts - about 16 per cent of Britain's needs - would have had on the national grid if it had been supplied by wind farms. The results showed that wind is highly volatile. In January 2005, for example, wind speeds varied so much that demand on conventional plants would have varied from 5.5GW to 56GW. As a result in that month a 1,000MW fossil fuel plant would have had to come on and offline a total of 23 times to make up the shortfall. At 6pm on February 2 2006 - the point of peak electricity demand for the whole year - wind farms would have been unable to provide any power at all, researchers found.

Gordon Brown's government have pledged to achieve 10 per cent of UK supplied electrical energy from renewable resources by 2010, and 20 per cent by 2020. The fact that this might be impossible need not concern Gordon, after all Labour will be out of power come 2011 and probably not back in power before 2020; so any failure to meet this target will be the fault of the Conservative party.

A spokesman for the British Wind Energy Association said:

"All the research we are aware of shows wind farms produce electricity for something like 80 to 95 per cent of the time... When you look at the UK system as a whole, there is electricity coming from wind 100 per cent of the time. There is no moment in time when the output of the pool falls to zero."

Now you have remembered the 4% figure haven't you? Well 4% is more than zero...