Scotland’s biggest energy firms have been paid £12million to shut down their giant turbines when the weather is too windy.
In total, more than £18million has been given to the owners of 19 windfarms since 2010 to stop them producing more electricity than the National Grid can cope with.
Two-thirds of the cash has gone to three of the country’s biggest energy companies – ScottishPower, Scottish and Southern Energy and npower.
Between them, they operate 13 windfarms which have received £12million in “constraint payments” from the National Grid to shut some turbines down.
This usually happens when winds are high and demand for electricity is low.
The payments are revealed as households struggle to cope with inflation-busting rises in heating bills.
And one energy expert warned that payments to the super-rich energy giants are set to soar again as the number of farms rises over the next five years.
The figures were collected by the Renewable Energy Foundation think tank, who oppose the spread of windfarms.
REF director John Constable said: “Consumers have every right to resent these payments and feel they are not getting value for money.
“The scale and pace of the Government’s ambition, both at Westminster and Holyrood, is exceeding our technical grasp to deal with wind power at reasonable cost to the taxpayer.
“This is the shape of things to come. It is not going to be a few million pounds a year. It is going to be tens of millions. This is simply not an efficient way of dealing with wind energy on the system.”
The SNP continue to harness Scotland’s wind and waves for energy. Incentives linked to the flagship policy have seen floods of applications for windfarms across the country and offshore.
But the extent of the planned developments has attracted flak from critics, including US tycoon Donald Trump, who claims a proposed windfarm off the north-east coast will ruin the views from his multi-million pound golf course at Menie, Aberdeenshire.
The biggest beneficiaries of constraint payments have been npower, who received £4.8million for turning off turbines at two of their windfarms.
This included almost £4.7million for not producing electricity at Farr windfarm, near Inverness.
ScottishPower were paid £4.1million for shutting down turbines at six of their windfarms in Scotland.
The Spanish-owned firm received £2.1million for keeping turbines at Whitelee, East Renfrewshire, idle over 19 days since May 2010. And they pocketed another £376,672 to shut down turbines at Whitelee for just one day in June last year.
With 140 turbines, Whitelee is Europe’s largest windfarm and was officially opened by First Minister Alex Salmond and ScottishPower chairman Ignacio Galan in 2009.
Last month, Labour leader Ed Miliband visited the huge complex on moorland near Eaglesham.
Scottish and Southern Energy have received £2.9million in constraint payments from shutting down turbines at six wind farms.
This includes £2.2million for switching off turbines at Hadyard Hill, near Barr, Ayrshire, for 43 days.
Other energy companies have also made millions from constraint payments.
Italian-owned Falck Renewables have been paid £2.3million to turn off turbines in Sutherland.
Their turbines at Kilbraur, near Brora, have been switched off 36 times since May 2010.
Dr Constable warned that constraint payments will soar as more windfarms are built.
Salmond has set a target of renewable energy providing half of the country’s electricity by 2015.
And windfarm developers have submitted more than 5500 planning applications since May 2007.
Last month, it emerged that the Scottish Government approved 83 per cent of all major wind farm applications submitted within the last five years.
Dr Constable said: “We are trying to show the developing world that you can go low-carbon at a reasonable cost. What we are actually doing is showing it costs a complete fortune.”
Over £900,000 was paid to windfarm operators for switching off their turbines last month alone.
Susan Crosthwaite, chair of Communities Against Turbines Scotland, said: “Constraint payments are just another part of the windfarm scam, adding to the already heavy burden on consumers and industry to pay for intermittent wind energy and its necessary infrastructure.
“It is systematically pushing more and more people into fuel poverty and fuel debt. More and more jobs will be lost as energy cost soar.”
Labour Shadow Energy Minister Tom Greatrex said: “Whilst constraint payments are sometimes necessary to effectively manage the electricity grid, there is a concern that energy companies are able to exploit the current system.
“ This will ultimately mean higher bills for already hard-pressed consumers.” Energy companies said most of the money paid out in constraint payments went to coal and gas power stations.
A ScottishPower Renewables spokesman said: “It is important that we have the capability to help National Grid balance the electricity system, although we would much prefer never to be told that we need to limit output from one of our windfarms.
“The constraint system, where generators may receive compensation when they are instructed by National Grid to stop or reduce production for a period, has been in place for electricity generators of all types for many years.
“Renewables are relatively new to the system, so we have worked closely with National Grid to fully understand how we can best respond to the needs of the system – and our bid price is one of the lowest across the wind industry in Britain.”
Scottish and Southern Energy said: “Constraint payments are made at times when National Grid need to balance supply and demand.
“The payments are not solely made to electricity generated from wind but other forms of generation, both conventional and renewables.”
An npower spokeswoman said: “The number of times that windfarms are constrained off is very small compared to conventional power stations, and this only occurs when the wind farm represent the cheapest option to National Grid.”
National Grid last night defended the payments.
A spokeswoman said: “The total cost for balancing the network in the 2011-12 financial year was £823million. This includes total constraint payments of £324million.
“These costs amount to less than one per cent of the average customer bill.”
Energy regulator Ofgem said: “We have long-standing concerns about constraint costs.
“Through our price controls on network companies, significant investment is planned for the high voltage grid which will have a major impact on helping to reduce constraint costs.”