The costs of offshore wind power generation could be brought down by one-third by the end of the decade, making this form of renewable energy commercially viable in the UK, according to new reports by the wind industry and government.

The findings are the latest salvo in the fierce battle over wind power, as critics tussle with wind proponents, ministers and environmental campaigners over the role it plays in UK's energy mix, with billions of pounds of investment at stake.

If realised, the steep drop in price would reduce the cost of using offshore wind by more than £3bn a year, and to generate one-fifth of the UK's electricity – in line with government targets.

Ministers have said about 18GW of offshore wind capacity should be built by 2020, more than an eight-fold increase on today's capacity. But at present, offshore wind is still one of the most expensive forms of renewable power, costing up to three times higher than onshore windfarms."