Current offshore foundation technology cannot be used for the next round of offshore wind farms, engineers warned this week.
Developing a new foundations system will be critical as Round 3 development sites are in deeper waters than previous wind farms.
“Steel monopiles will not be suitable in 30m depths, there’s a certain point at which they no longer work”, said Atkins Energy managing director Martin Grant.
Most offshore turbines around Britain are in water which is 20m deep or less. Yet 70% of the new raft of wind farms will be in depths of 30m or more, with some in water up to 60m deep.
The Carbon Trust, an independent company set up by the government to help reduce carbon emissions and commercialise low carbon technologies, is working to develop the technology necessary for Round 3 wind farms.
“It’s a completely different engineering challenge to embed these turbines. New technology is needed for deeper water conditions and larger, heavier turbines,” said Carbon Trust senior technology acceleration manager Benj Skyes.
“The big challenge is ensuring this new technology is commercially viable.”
Four new prototypes are being trialled by the Carbon Trust.
Meanwhile, consultant Gifford is pioneering a large concrete gravity base structure which will be ferried to site by submersive transport and an installation barge (NCE 26 November 2009).
Dutch firm Suction Pile Technology has put forward a self installing foundation solution.
US consultant Keystone Engineering is developing a spider-like tripod with three supporting legs angled around a central pile in a twisted jacket. Another US firm, marine consultant Glosten Associates has proposed a floating wind turbine which comprises a buoyant hull, tendons and an anchorage system.
Foundations currently account for half the capital cost of offshore wind farms.