This conclusion starkly contradicts suggestions by some commentators that renewable energy is made much more costly or even drastically limited by intermittency.

The assessment on the costs and impacts of intermittent energy supplied by renewable sources finds the vast majority of international expert analysis dispels the intermittency myth. And, while the output of fossil fuel plant will need to be adjusted more frequently to cope with fluctuations in output, any losses this causes are small compared to overall savings in emissions, the study claims.

The report, which reviewed evidence on the costs and supply system impacts of intermittent generation from more than two hundred reports and studies, also concludes that it is unnecessary to provide a 100% reserve capacity for individual renewable sources. While extra capacity is needed, the requirements are modest, accounting for a small part of the total cost of renewables with intermittency accounting for around 1% of electricity costs, the study finds.

The report also concludes that the costs of intermittency at current levels are much smaller and that, while this would be expected to rise, with a wide geographical dispersion and a diversity of renewable sources costs will be kept down.

Robert Gross, head of UKERC’s technology and policy assessment function, said: “The output of wind, wave and other renewables fluctuates and cannot be fully controlled. The extent to which this is likely to create problems, costs or even lead to black outs is the subject of a long running debate. Reports that suggest it is highly costly, or restricts the role of renewables are out of step with the majority of expert analysis. However, costs will rise to a degree.”

Irish renewables developers Airtricity welcomed the report with chief executive Mark Ennis saying: “Now that the myths of system reliability and variability have been dispelled, serious consideration should be given to 30% penetration of wind energy in the UK’s energy mix. We compete in a world market for fossil fuels with China, India and the US – but not for the wind that so freely blows over our shores.”