The main objective of the project was the development of a rotor blade from new fibres, e.g. general purpose (GP) carbon fibre, as well as matching manufacturing techniques in order to build large, cost effective, high quality wind-turbine rotor blades. Depending on the savings in production costs it is envisaged that the total cost reduction for a blade will be up to 20%.
The following conclusions may be drawn:
1.General-purpose Carbon fibres (GP) are not as cost effective as the generally applied high strength fibres (HS). Although the costs of GP fibres is less, the material properties decrease by the same amount. During the time of the project the GP fibres were only available as uni-directional fabrics.
2. The combination of carbon HS material and glass matrix material, (also mentioned as hybrid material) is a promising material layout. The material properties are only slightly less compared to full carbon HS laminates and the costs are significantly lower.
3. A blade cost evaluation showed that carbon blades are (for any blade length) more costly compared to fibre-glass blades. Carbon blades are only applied in cases where the design specifications are very strict regarding low weight and maximum stiffness.
4. Hybrid (combination of carbon and glass) material seems to be a cost effective alternative for carbon and fibre-glass blades. An example: in changing the carbon material for fibre-glass material the costs of the rotor blade of the LW30/250 wind turbine decrease by approximately 15 % to 20%. The hybrid LW30/250 blade is of the same cost level as comparable glass blades, however, the weight is significantly lower and the stiffness higher.