Wind power would be too unreliable to meet Britain’s electricity needs, according to a new report.
It says wind patterns around the country mean turbines will fail to produce enough power at times of high demand.
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.
It comes after the Government last week unveiled a £100million plan to build at least 4,000 wind turbines, with a further 3,000 offshore. The programme is expected to drive household bills up by £260 a year.
Published online in the journal Energy Policy, the study confirms concerns among critics that wind around Britain is too volatile to provide reliable energy.
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.
Backup fossil fuel plants would need to be switched on and off to make up the shortfall in supplies – a highly inefficient process that would reduce any carbon savings from wind farms.
The report says: “Wind output in Britain can be very low at the moment of maximum annual UK demand. These are times of cold weather and little wind.
“Simultaneously, the wind output in neighbouring countries can also be very low, and this suggests that intercontinental transmission grids will be hard to justify.”
The 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 show 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.
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.
Britain aims to achieve 10 per cent of its supplied electrical energy from renewable resources by 2010, and 20 per cent by 2020.
James Oswald, an engineering consultant and former head of research and development at Rolls-Royce Turbines, who led the study, said: “Wind power does not obviate the need for fossil fuel plants, which will continue to be indispensable.
“The problem is that wind power volatility requires fossil fuel plants to be switched on and off, which damages them and means that even more plants will have to be built. Carbon savings will be less than expected, because cheaper, less efficient plant will be used to support these wind power fluctuations.
“Neither these extra costs nor the increased carbon production are being taken into account in government figures for wind power.”
Critics say the Government should use other forms of renewable energy, such as tidal power, to meet targets. Wildlife groups also oppose wind turbines because they are built in isolated locations and may kill birds of prey.
But 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.”
By Roger Dobson and Richard Gray
29 June 2008