France: Vallourec Presents New System for Offshore Wind Turbine Anchoring

Vallourec, world leader in premium tubular solutions, presents its patented PREON® marine tubes system designed to anchor offshore wind turbines to the seabed. Developed by Vallourec’s R&D teams, this solution will mean that offshore wind turbine foundations can be installed with less effort, noise and at a lower depth, compared to the two existing solutions.

The area needed to install the PREON® marine system is considerably smaller than that of the “gravity system” based on concrete foundations, which take up as much space as a football pitch. Furthermore the lighter system with a smaller external pile diameter is drilled approximately 20 metres into the seabed, compared with the usual 60 metres of systems with anchoring piles. Finally, when the PREON® marine system is installed noise pollution is limited to around 75 decibels – similar to the noise made by a bicycle bell – compared with the 200 decibels generated by the 3,000 hammer blows required to drive the anchoring piles into the seabed. Such a sound level, higher than that of a plane taking off, is harmful to marine life and limits the scope for installation in tightly regulated areas.

Requiring less material than existing solutions, PREON® marine will offer a scope for faster, cheaper installation, opening up new economic prospects. Thanks to this system, companies will be able to establish installations in areas of the North Sea and the Baltic Sea that are subject to strict environmental regulations.

“The market for offshore wind power is expected to grow strongly in the coming years and Vallourec has developed an innovative solution for this market which generates savings in terms of materials, time and money and at the same time preserves the environment”, noted Andreas Denker, Managing Director of Vallourec’s Industry Activities.

The European Wind Energy Association (EWEA) is forecasting up to 40 GW of installed generating capacity in the North Sea and the Baltic Sea by 2020. With the most powerful wind turbines currently generating 5 MW, this adds up to the installation of some 8,000 offshore wind turbines by 2020. By 2030, the EWEA forecast is for an offshore installed generating capacity of 150 GW, or the equivalent of a further 20,000 units between 2020 and 2030.

PREON® marine: smart weight distribution

Vallourec’s new tube system breaks with conventional anchoring systems by distributing the weight of offshore turbines differently. The loadbearing frame made from seamless steel structural hollow sections (MSH) presents a hexagonal base to the seabed. In each corner up to three steel threaded injection piles are drilled into the seabed to a depth of only 20 metres and anchored there. With this hexagonal system, the surface of the foundations resting on the sea floor is much less important than that of traditional concrete systems.

Furthermore, the structure is entirely reversible.

PREON®: a tried and tested tube system solution

PREON® marine is part of the PREON® product line, a patented tubular roof frame system developed for industrial and commercial buildings. The MSH-type seamless structural steel hollows are used in light yet strong constructive projects requiring wide spans. These can be erected 50% more rapidly than conventional structures. The resulting buildings use fewer raw materials and energy during the construction process.

[mappress]

Offshore WIND staff, March 30, 2012; Image: Vallourec