Hundreds of offshore wind turbines could be suffering from a design flaw that makes them sink into the sea.
Energy company engineers are urgently investigating the extent to which their offshore wind farms are affected, after flaws were discovered on a Dutch wind farm last autumn.
The problem could cost £50 million, said Renewables UK, the industry body that represents wind farm developers. It says that almost all of the 336 offshore turbines that have been erected could be affected as these were built to European standards now in question.
The problem arises in the concrete used to fix the turbine to its steel foundation. Shell found that some of the turbines at Egmond aan Zee, its Dutch wind farm, had moved a few centimetres. Centrica, owner of British Gas, and Dong Energy, the Danish wind group, admitted potential problems with some of their UK farms, but added that there was no safety or operational issue.
Peter Madigan, head of offshore renewables for Renewables UK, said: “A fault has been identified and has been shared with the industry, which has moved to see if there is a larger problem.” If repairs are necessary, energy companies will do them one turbine at a time to keep energy losses down.
Dong Energy said that three of its offshore wind farms were affected, including Gunfleet Sands, which has 30 turbines off the Essex coast, and Burbo Bank, which has 25 turbines in Liverpool Bay. Centrica said that it was investigating its Lynn and Inner Dowsing wind farm in the North Sea but that its Barrow offshore farm was not affected. However, the industry must revise its design standards before the next round of wind farm construction.
Installation of 175 turbines on the giant London Array offshore wind farm off the Essex coast, in which Dong Energy and E.ON are partners, was due to take place this year. When completed, it is hoped that London Array will provide half the Government’s target of providing 15 per cent of UK electricity from renewable sources by 2015.
A spokesman for Dong Energy said that an appropriate solution would be found for London Array and that Dong was talking to its lawyers about who should pay for the problem.
The offshore wind industry has been at the heart of the UK economy’s shift to low carbon by Labour, but the cost of developing it, although it is heavily subsidised, is high and planning consents have proved difficult to obtain.
Experts say that although the UK coast is one of the windiest in the world, wind farms do not provide the sort of flexible power that Britain will need when its coal-fired and nuclear generators begin to close over the next decade.
Times Online, 14 april 2010 – "Sinking turbines blow ill wind across offshore energy sector."