The Department for Energy and Climate Change says it has "needed to drive through reforms to secure investment in new generation to keep the lights on in the years and decades ahead" after suggestions it may have cost consumers by awarding eight renewables contracts too early.
A spokesperson said the National Audit Office's report recognises that the early deals were "designed to offer better value to bill-payers" by reassuring investors.
"Without that investment, projects would have been unable to go ahead or been significantly delayed - putting our future energy security at risk."
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Nearly 38,000 runners will hope to complete Sunday's London Marathon making it the biggest event in its 35-year history.
Rain across central Britain with longer, intense downpours with thunder in places this evening. A lucky few will stay sunny and dry.
Planning on going to the London Marathon tomorrow? Read our handy guide first!