Page 70: of Offshore Engineer Magazine (Sep/Oct 2013)

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EPIC

Several bucket foundations are shown during manufacture at the Harland & Wolff shipyard in Belfast, Northern Ireland. The worker walking underneath gives a perspective on the dimensions of the upturned bucket design. Photo: Fred. Olsen United station at the Horns Rev 2 wind turbine “The traditional foundation relies Clarke notes the bucket’s advantages, site, also in Danish waters.

on a grouted connection, and in recent saying that it was chosen for two met years, failing grout connections have Two other bucket foundations are masts because it uses less steel than gained the attention of industry experts under contract for met stations; one at conventional piled foundations and its and could result in huge upgrade Dogger Bank, and for the Seagreen tur- design removes the need for pile driv- investments for already operational bine site in Scotland’s Firth of Forth, ing, seabed preparations, scour protec- wind farms,” Langkilde says. Langkilde says. tion and a transition piece.

Universal points to the bucket’s com- It is too early to say which founda- “We have taken our requirements for parative ease of decommissioning and tions will be used for the wind turbines met masts to look beyond the standard removal, which allows it to be reused at Dogger Bank as that decision will approach and instead use the opportu- or recycled, cutting costs even more. be made by the lead operators of the nity to demonstrate a new, and poten-

Complete removability also is an various parts of the sprawling develop- tially very exciting, technology with environmental beneft. When a site is ment, a Forewind spokeswoman says. possible benefts well beyond just the decommissioned, pulling the bucket But Forewind General Manager Lee Dogger Bank development,” he says. completely out returns the seabed to its prior condition. Traditional monopoles often are cut off at the seabed with their bottoms left embedded.

Promoters also tout the lower envi- ronmental impact of installation. Unlike conventional foundations, Universal’s requires neither pile drivers nor vibra- tion machines that disturb marine life.

Two other Universal bucket founda- tions have been installed; one in 2002 to support a 3-MW demonstrator turbine at

Frederickshavn (harbor), Denmark, and a second in 2009, to carry a meteorological

Two bucket foundations loaded aboard the Fred. Olsen Windcarrier jackup, prepared for installation of a meteorological station at Dogger Bank, in the North Sea. Photo: Fred. Olsen United

OE | September 2013 oedigital.com 72 070_OE0913_EPIC4 forewind.indd 72 8/18/13 8:35 PM