Sustainable Vacuum-Infused Thermoplastic Composites for MW-Size Wind Turbine Blades—Preliminary Design and Manufacturing Issues

This paper addresses the feasibility of using innovative vacuum infused anionic polyamide-6 (PA-6) thermoplastic composites for MW-size wind turbine blades structures. To compare the performance of this fully recyclable material against commonly used less sustainable thermoset blade materials in a baseline structural MW-size blade configuration (box-spar/skins), four different blade composite material options were investigated: Glass/epoxy, carbon/epoxy, glass/PA-6, and carbon/PA-6. Blade characteristics such as weight, costs, and natural frequencies were compared for rotor blades ranging between 32.5 and 75m in length, designed according to both stress and tip deflection criteria. Results showed that the PA-6 blades have similar weights and natural frequencies when compared to their epoxy counterpart. For glass fiber blades, a 10% reduction in material cost can be expected when using PA-6 rather than epoxy while carbon fiber blades costs were found to be similar. Considering manufacturing, processing temperatures of PA-6 are significantly higher than for epoxy systems; however, the associated cost increase is expected to be compensated for by a reduction in infusion and curing time.