CONTROVERSIAL wind farms ground to a virtual standstill during the New Year cold snap just as the freezing temperatures saw a soaring demand for electricity.
Energy experts are questioning the Government's desire for a massive expansion of wind power after officials admitted onshore turbines were working at as little as five per cent efficiency during the height of the cold weather.
Official figures – which record the performance of half of the UK's onshore turbines – have revealed the problems caused by a lack of wind.
On the coldest day they produced five per cent of their maximum output, on another they produced just nine per cent, and on two further days the figure was 10 per cent, prompting critics to claim they are "as useful as a chocolate teapot" when electricity demand is at its highest.
The Government insists "intermittence" in production by wind turbines is manageable and Energy Secretary Ed Miliband has made clear his backing for wind power as the Government seeks to produce 20 per cent of power by renewable means in 2020.
But the figures, released by Energy Minister Lord Hunt, give ammunition to critics concerned that consumers will face increasingly expensive electricity bills to pay for renewable energy.
Dr John Constable, director of policy and research for the Renewable Energy Foundation, a UK charity publishing data and analysis on the energy sector, said: "Extremely low wind power output at times of cold weather and high electricity demand are well documented in Germany and Denmark, and it is not surprising that they also occur in the UK.
"We have to be realistic and acknowledge that no matter how much wind we have UK plc will still require conventional, gas, coal, and nuclear power stations equal to peak load (60 GW) plus a margin to stay in business.
"The technical and economic difficulties of running large scale wind power with that indispensable conventional fleet are real, and greatly underestimated by government. There is even a risk that by going too fast with wind we end up with a system that is dirtier than it would otherwise have been, and unreasonably expensive."
The Government figures – which measured electricity produced by wind between 5pm and 6pm when demand was highest – showed that the onshore turbines were producing just 72MWh of power on January 7, just five per cent of the maximum they could have produced – 1,565 MWh. Only on four days in the first half of January did they reach 50 per cent.
Wind is a crucial part of the Government's plans and Mr Miliband has said it should be as socially unacceptable to oppose wind turbines in their areas as it is not to wear a seatbelt.
But many plans for onshore turbines have proved highly controversial. The Government recently announced deals for the latest wave of offshore farms, including one near Hornsea, which it is hoped will meet less opposition.
Godfrey Bloom, UKip MEP for Yorkshire and the Humber and an outspoken critic of wind farms, said they were "about as much use as a chocolate teapot" during the cold weather.
A Department of Energy and Climate Change spokesman said: "The UK has one of the best wind profiles in Europe and as such, wind technology has the potential to supply a significant proportion of our future energy needs.
"We believe that intermittence is manageable. It will be possible to generate significant amounts of electricity from wind for the majority of the time. This is managed through having a diversity of generation sources as back-up for the times when wind turbines are not generating."