Hundreds of European offshore wind turbines have a design fault allowing them to slide on their bases and finding a solution could take months and cost millions of pounds, European turbine makers and wind farm operators said.
Swedish turbine maker Vattenfall is also investigating three of its offshore wind farms, but declined to comment on how long the inspection would take or how much the solution might potentially cost.
The problem involves towers using grouting, a mixture of cement, sand and gravel, to attach the turbines to their base, they said, reported Reuters. In some cases the main superstructure of wind towers has moved several centimetres on its base after being installed.
It is an industry-wide problem related to a general design and not one particular tower model, industry executives said. It is not expected to delay new projects nor hit electricity production.
"We expect to have settled on a solution in the next four to six months. For the wind farms under construction, including London Array, we have made some design changes in relation to this issue," a spokesman for Denmark's Dong Energy said. "It will not delay the London Array project as foundation work has not started yet."
Dong owns half of the one gigawatt London Array offshore wind project in southeast England where construction is expected to start in 2011. Germany's E.ON owns 30 percent and Abu Dhabi green investment firm Masdar owns 20 percent.
Dong has problems at the UK Dogger Bank and Gunfleet Sands wind farms, as well as the Danish Horns Rev 2 facility. The company estimates it could cost up to £13 million to restructure all 164 turbines.
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