Energy firms will receive thousands of pounds a day per wind farm to turn off their turbines because the National Grid cannot use the power they are producing.
Critics of wind farms have seized on the revelation as evidence of the unsuitability of turbines to meet the UK's energy needs in the future. They claim that the 'intermittent' nature of wind makes such farms unreliable providers of electricity.
Whereas coal and gas power stations often pay the National Grid £15 to £20 per megawatt hour they do not supply, Scottish Power was paid £180 per megawatt hour during the test to switch off its turbines.
It raises the prospect of hugely profitable electricity suppliers receiving large sums of money from the National Grid just for switching off wind turbines.