A one-year feasibility study, funded by the Technology Strategy Board, is being carried out by TWI and Graham Engineering Limited, to examine the potential of thick-section laser welding processes for offshore wind turbine fabrications. The welding study - the LaserJacket project - is already producing results that could eventually change industrial practices in the EU and bring about viable, cost-effective and high-volume production alternatives not only for offshore wind turbine support structures, but other fabrications with thick section joining requirements.
Currently, the manufacture and installation of wind turbine support structure components, in particular non-serial wind turbine jackets (or space frames), involves a reliance on labour-intensive conventional arc processing. These account for around 66% of the total cost of foundations.
With the predicted ramp-up in offshore wind energy production, future generations of wind turbine support structures will, for the most part, be deployed further from shore, thus accessing higher wind speeds. Jacket structures are one potential solution to the engineering challenges that such deployment will raise. Nevertheless, as this market grows, it will come up against the current productivity limitations imposed by the arc welding fabrication methods presently in use. Consequently, industry adoption of alternative welding methods, including laser welding, could boost productivity - as will be needed in the nearer term - reduce manufacturing costs and, ultimately, the levelised cost of energy of offshore wind energy.
The LaserJacket project team is part-way through an initial evaluation programme to develop laser welding techniques suitable for section thicknesses outside the current capabilities of lasers, up to an industry relevant steel thickness of 60mm. The team is comparing the joint completion capabilities, efficiency and cost-effectiveness of the techniques, both with respect to each other, and against other welding techniques already in use or being considered by the offshore wind industry. Complementary assessments of weld qualities and properties to pertinent international standards are also being carried out by TWI.
At the end of the project, LaserJacket will deliver knowledge on the applicability of the techniques, produce thick-section laser welding procedure knowhow, and an equipment configuration design suitable for future application to thick-section laser welding of selected joints in turbine jackets.
The findings and developments of the project will be presented to industry as part of a special demonstration day to be held later at Graham Engineering Limited in Nelson, Lancashire in mid-2014.
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