Operators of wind farms were paid £34 million to switch off turbines during gales – millions more than previously thought – it was reported.
Figures also showed that last week energy firms were effectively handed £400,000 by householders for doing nothing, under the arrangement.
The wind farms are paid to stop by the National Grid, which cannot cope with the extra energy produced by the high winds.
But the exact structure of the payments – that are passed on to householders in the form of higher energy bills – have been mired in secrecy.
It was previously known that the Grid had paid £15.5 million in the form of “constraint payments” to operators in 2011-12 in England and Scotland. This represented money given to them to shut off supplies when supply outstripped demand.
However, figures relating to so-called “forward trades”, in which the National Grid pays out when the weather is expected to be stormy, have now also been revealed by a newspaper.
Limited information about this money, which is paid out even before a turbine is shut down, was published on an obscure section of the National Grid website.
These “forward trade” payments amount to £18.6 million, bringing the total payments for that year to £34.1 million, far higher than previously reported, according to the Daily Mail.
Meanwhile on Monday and Tuesday last week during high winds, the National Grid paid £16,118 in compensation to wind farm operators. But the total figure including forward payments was £387,000, the newspaper said.
Murdo Fraser, a member of the Scottish parliament, said: “The revelation that vast sums are being paid to wind power developers will just lead to more and more people questioning government policy.”
National Grid spokesman Chris Mostyn said constraint payments were just one of the “tools” used to help “balance the network minute by minute and keep the lights on”.
He added: “We are always working with the industry to improve and develop the way we operate the Grid, as well as investing millions of pounds in the coming years to help move the power to where it’s needed.”