Second Dogger met-mast in place

The second of two new-look meteorological masts has been erected at Forewind's giant Dogger Bank wind power development off the UK by Fred Olsen Wind Carrier jack-up vessel Brave Tern.

Dogger Bank Met Mast West, which will feed back key wind, wave and other weather readings as well as marine traffic data from its location 150km off the UK, uses an innovative "suction bucket" foundation concept and a “human free” technique for the steel tower placement.

The flask-shaped,165-tonne steel foundation, designed by Fred Olsen-owned Universal Foundation, was installed by applying suction in the bucket-shaped base to pull it into the seabed, while hundreds of built-in water jets kept the structure level. 

The met-mast's 93-metre lattice tower was manoeuvred into place using a “human free” technique employing guide cones.

“The scale and scope of the Round 3 projects like Dogger Bank will continue to provide ongoing opportunities to introduce innovative technological advances and improved methods that will help reduce costs and improve efficiencies industry-wide,” says Forewind general manager Lee Clarke.

The suction bucket foundation, developed with support from the UK Carbon Trust's Offshore Wind Accelerator (OWA) programme, was fabricated at Harland & Wolff’s facility in Belfast.

“Novel foundations being developed through the OWA are essential to rapidly reduce the capital costs of the next large-scale offshore wind farms," states Carbon Trust associate director for innovation Phil de Villiers.

Dogger Bank Met Mast West is expected to be fully operational by the end of September. It sister met-mast was installed earlier this year.

The deployment of the latest met-mast was delayed at one stage earlier this year by "technical factors".

Installation of the foundations marks the first stage of construction at the up-to-9.6GW Dogger Bank zone where water depths range from 18 to 63 metres. Forewind comprises industry heavyweights Statoil, Statkraft, SSE and RWE.

A third suction bucket foundation is being built at Harland & Wolff for the SSE/Fluor SeaGreen joint venture for a met-mast to be installed in 43-metres of water at its Firth of Tay zone off eastern Scotland.

Earlier models of the concept, which can fix itself into “80-90% of soil types" according to Universal Foundation, have been used for a Vestas V90 erected off the Danish port of Frederikshavn in 2002 and for a mobile met mast installed at the Horns Rev 2 wind farm in 2009.