Wind turbines switched off on 38 days every year 

Wind turbines will have to be switched off on 38 days every year because it is too windy, the National Grid said yesterday.

In a new report, the grid said it could not cope with the surge of power from wind farms and will have to switch off turbines to avoid overloading the power transmission networks.

The admission casts doubt on the Government’s decision to push for a seven-fold increase in the amount of electricity generated by wind by 2020.

Wind farm operators are given “constraint” payments to keep their turbines idle and some experts believe this will cost almost £300 million a year by 2020, with the cost passed on to consumers.

The National Grid fears that warm and breezy summer nights could cause a surge in the electricity, combined with a lack of consumer demand. The electricity cannot be stored, so one solution – known as the “balancing mechanism” – is to switch off or reduce the power supplied.

They are currently switched off on 25 days a year, but the National Grid says this will have to increase significantly as more turbines are built.

Wind farm operators were paid £2.6 million to keep their turbines idle last month in the latest stealth charge on household power bills and the cost of switching them off is likely to rise.

Last week Scottish Power, one of the “Big Six” energy firms, said it will increase gas and electricity bills by 19 per cent and 10 per cent respectively from August – adding £175 a year to the average bill.

According to data from National Grid, which operates the main power and gas transmission networks, Britain is expected to increase wind power capacity seven-fold by 2020 to 26.8 gigawatts, which would put additional strain on the transmission network.

Wind farm operators are paid large subsidies, with more than £500 million going on wind power last year under the Renewables Obligation, the Government’s mechanism for supporting renewable energy. The average turbine is understood to generate power worth about £150,000 a year, but is awarded incentives in the form of subsidies worth £250,000.

Dr John Constable, director of policy and research at the Renewable Energy Foundation, said: “This work from National Grid acknowledges that wind power may cause very high system management costs in 2020, at around £286 million a year. When combined with the required subsidy costs of upwards of £6 billion a year in 2020, the consumer burden entailed by the renewables policy is looking increasingly unsustainable.”

Campaigners have fought wind farms throughout Britain, insisting that they do not produce the amount of electricity claimed and also blight views.

A grid spokesman said cutting wind generation output had involved a small number of wind farms each time over a few hours: “Over the past year we have had to reduce output from wind generators on 25 days, amounting to less than half of one per cent of the output of wind generation connected to the high-voltage transmission system over the same period.”