UK to test offshore 'suction bucket'

A group of offshore wind majors led by Norway's Statoil plans to pioneer installation of so-called "suction bucket" turbine foundations at test sites around the UK North Sea later this year as part of a £6.5m joint industry trial aimed at slashing the cost of offshore wind power.

The demonstrator, set to be carried out in the third quarter, will see deployment of Danish contractor Universal Foundation's (UF) new-look concept -- a bucket-shaped foundation base that is sunk into the seabed and leveled using hundreds of of built-in water jets -- on the giant Dogger Bank, Hornsea and Dudgeon development zones.

"The suction bucket foundation is a really great innovation for the industry as you can install it faster and at lower costs than conventional steel foundations," says Jan Matthiesen, director of the UK Carbon Trust’s Offshore Wind Accelerator.

OWA is shepherding the project that also involves developers Statkraft, EON, DONG Energy and Denmark's Aalborg University.

"That is good for developers and for consumers as it means it brings down the cost of offshore wind energy.  This trial is critical as it will determine the extent to which it can be applied for future offshore wind projects."

New-generation foundation concepts such as the suction bucket are calculated to have the potential to cut the capital spend on offshore wind energy by up to £1bn over the next decade while reducing the cost of energy by 10% from the 2,500 turbines expected to be deployed off Europe in this time-frame.

Jan-Fredrik Stadaas, Statoil's technology manager for offshore wind, states: “This is an important industry project, demonstrating cost reduction through industry collaboration and partnering. It represents also a de-risking activity, moving technology further and securing future cost reductions in the offshore wind market."

UF has teamed up with Norway's Windcarrier -- both owned by Fred Olsen -- to carry out the trials at sites with varying soil conditions to flesh out the range of uses for the suction bucket, one of four novel low-cost foundation designs shortlisted through an international competition run by the Carbon Trust in 2009.

A pair of UF suction buckets are currently installed at Dogger Bank -- a 9.6GW zone where waters are 18-63 metres deep -- as foundations for two meteorological masts. A flagship unit topped with a 3MW turbine has been in place off Frederikshavn, Denmark, since 2002.

UF chief Torgeir Ramstad says: “We believe [this technology] will bring substantial cost reductions to future offshore wind farms. Not only are we able to install in a wide range of soil conditions, carrying the largest turbines in deeper waters, we can accomplish installation of turbines immediately following foundation installation thus entering the production phase much faster."

The latest version of the UF suction bucket foundations will be deployed at each new site, then removed and transplanted to the next site for testing.