Cost Effective Large Blade Components by Using Carbon Fibres Available to Purchase

Due to the increasing size of wind turbine rotors, especially for offshore wind turbines, the power output and the blade mass are becoming more important. A new type of cheaper carbon fibres is expected to result in a lower blade mass and marginally cheaper blades. In a Joule-funded project, the possibilities for economic use of carbon fibres is determined by establishing material design data, analysing production methods, developing cost-effective blade root joints and assessing blade and turbine costs. The R&D project will be finalised by the end of 2001. Up to now, production processes and promising material combinations have been reviewed, tested and ranked. Basic material design data have been established for the two most-promising material combinations. Due to disappointing fatigue results on Panex/VE, additional testing on four large-tow laminates was performed. The fatigue properties of these showed to be consistent. Later testing on a similar Panex/epoxy laminate, however, revealed much better fatigue behaviour. Joint development and cost assessment are underway and show promising results.