Regulations which dictate where offshore wind farms can be built must be relaxed, according to a report from the Carbon Trust.

According to the Trust building wind farms far offshore adds great expense to the schemes and deters investment. It says allowing wind farms to be built nearer to the shore and in shallower waters is the key cost-saving measure that would enable 29 GW of offshore wind farms to be built by 2020.

Other recommendations in the report Offshore wind: big challenge, big opportunity include removing grid and planning regulatory barriers, increasing public R&D funding and modifying the current incentive mechanism.

Tom Delay, chief executive of the Carbon Trust said: "If we are to meet our 2020 renewable targets we need a dash for wind on a comparable scale to the dash for gas of the 1990s. Slashing the costs of offshore wind must now be a priority for UK energy policy.

"The government must use the upcoming consultation on this important issue to unlock the most economically attractive sites for development. This would dramatically reduce the cost of development - essential if we are going to meet our 2020 renewable targets and deliver significant reductions in our carbon emissions."