French energy giant EDF has been ordered to repay £5.5 million after overcharging the UK electricity grid to keep the system balanced during periods of oversupply.
EDF’s Dorenell Windfarm Limited (DWL) charged “excessive prices” when it was asked to reduce its output, Ofgem has ruled.
The regulator will pay wind farms to turn off supplies when there is too much electricity for the Grid to handle, but EDF’s bill was "excessive" it said.
“Ofgem considers that DWL charged excessive prices to reduce output where this was required to keep the system balanced, and the breach pushed up costs for consumers,” Ofgem said in a statement.
Assumptions made by the company were higher than necessary and its prices “did not properly reflect the financial benefits of reducing its output," said Ofgem's statement.
EDF said it would pay the £5.5 million into its voluntary redress fund, which helps struggling households.
Ofgem director of enforcement Cathryn Scott said: “Customers – particularly those in vulnerable situations – will rightly benefit from over £5 million as a direct result.
“We hope this sends a clear message that licence breaches will simply not be tolerated.”
DWL said it “accepts it made an unintentional breach of the Transmission Constraint Licence Condition (TCLC)".
The Dorenell wind farm is in the north-east of Scotland.
Previous repayments under the Redress scheme include Drax (£6.12 million), SSE Generation (£9.78 million) and EP SHB Limited (£23.63 million) .