Statoil starts Hywind current work

Statoil has begun profiling the offshore currents at the development site of first floating wind power array demonstrator, Buchan Deep, now cleared to be built in deep waters off the north-east coast of Scotland.

Australian contractor Metocean Services International (MSI) has moored a current measurement device 25km off the coast of Peterhead for the pilot, which will consist of a quintet of 6MW second-generation spar-based machines daisy-chained together in water depths of 107 metres.

“Although current profile measurements are relatively straightforward in this water depth, the challenge on this project was to design a system to enable recovery of the anchor weights, this in order to comply with environmental legislation,” states MSI’s Stefan Stimson.

The next-generation Hywind 2, a cylindrical concept ballasted with water and gravel to balance in depths of more than 200m secured by a three-point mooring spread, has been fine tuned with its hull’s draft trimmed to a more compact, lighter “site-optimised” design that stretches 76 metres below the surface.

Increasing the turbine size while decreasing the draft is designed to make the Hywind 2 more cost-efficient than the Norwegian demonstration unit, the 2.3MW prototype built with contractors Technip and Siemens, and installed in 2009 off the coast of Norway.

Operating in winds of up to 40 metres per second and waves as high as 19 metres, the floater has flowed 26GWh to date, a yield Statoil calculates to be 30-40% higher than a “typical land turbine” and 10-20% higher than conventional monopile-mounted offshore machines.