OBJECTIVES OF THE PROJECT
Large wind turbines are expected to be more cost effective and have a higher efficiency. For these turbines low weight, stiff blades are preferred with thin, high lift airfoils. Stiff light-weight blades can be accomplished when carbon fibre reinforced plastics are used. Present material knowledge and usage and production methods result in relative expensive blades. The aim of the project is to enable the economical use of carbon fibres reinforced plastics (CFRP) by establishing material design data and suitable production and joint techniques.
The following activities take place:
- establishment of CFRP material design data
Material design values are established after selecting optimal 'wind turbine' laminates. Special attention will be given to increase the relatively low compressive strength.
- development of a cost-effective blade root joint
Durable blade root connections will be developed, based on existing joint types, produced and tested.
- evaluation of production methods
Existing CFRP manufacturing techniques are reviewed leading to recommendations and followed by pilot production of a re-designed tip shaft.. - assessment of blade and turbine costs
The influence of the amount of CFRP on the tip deflection and a cost assessment of the rotor costs and turbine costs for a hybrid or full carbon blade will be given.
With the above the potential of large CFRP rotors will be evaluated in terms of performance and costs with reference to glass reinforced blades.
EXPECTED ACHIEVEMENTS AND EXPLOITATION
Due to an optimised manufacturing method for large blades, high quality blades can be produced with improved (compressive) strength. The establishment of material design data will enable higher material strength; together with improved structural joints this will result in light-weight, cost-effective carbon fibre reinforced rotor blades.
Blade costs of the hybrid blade are expected to become 125% of full-glass blades. For off-shore turbines this cost increase is expected to be counter-balanced by higher energy output. In the optimistic case of comparable tensile and compressive strength of the material, the blade cost of the hybrid blade will be similar as a full-glass blade. This would enable the use of hybrid material for conventional blades.
The involved blade manufacturers intend to review the project results for their next generation of rotor blades. In view of the number of blade manufacturers and their position on the European market it can be expected that wind turbine manufacturers will adopt the CFRP blade as a de-facto standard.
Funding SchemeCSC - Cost-sharing contracts
1704 RN Heerhugowaard
2600 GA Delft