How can composites help?
Most wind turbine blades are made with a hand lay-up process, which can lead to manufacturing defects and lack of consistency. As the wind energy industry moves towards more composite material use in wind blades, manufacturing processes that have been pervasive in the aerospace and defense industries for the manufacturing of wings, fuselages and helicopter rotor blades, need to be more heavily utilized. Specifically, automation in manufacturing around fiber placement and the manufacturing and use of pre-pregs or pultruded rods for structural members in the blades are the largest areas of innovation being talked about right now in the wind sector, says Totaro.
Component Weight Reduction & Transportation
“With turbines getting bigger in physical size, we can see that load mitigation and construction are emerging focuses,” says Totaro. Component weight reduction encompasses optimization of the total mass to maintain a tower head mass ratio (mass per energy output of the turbine) as well as cost out programs to minimize capital cost of the turbine. Transportation cost reduction associated with getting components to a wind farm site from a factory and installation also require attention. To address these problems, manufacturers are investigating advanced materials such as composites over metals. “A large reason for the shift to eliminate the gear box is because with the heavy mass on top of the tower, it has the potential to introduce cost inefficiency. In other words, an OEM is overpaying on a cost that affects product competitiveness. Thus, a large portion of R&D is going into reduction of the mass and cost of components that are at the top of the tower,” explains Totaro. “In regards to transportation, shipping turbines in modular sections and assembling on-site at a wind farm will be an important area of investigating for land-based turbine manufacturers. Component size has increased to such an extent that transportation of whole blades, towers, and nacelles under bridges and through tunnels is reaching its limit.”
How can composites help?
Materials science R&D will be the most dominant force in influencing the renewables industries over the next 20 years, according to Totaro’s firm. “In any industry, material science ends up being the largest influence in creating change in technology. Some manufacturers would choose to make the blades, the nacelle and even the tower (currently made of tubular steel) of a wind turbine out of composites if it would be cost effective,” he says. Blades are still made from fiberglass and balsa wood due to the input cost comparison with composites, but as components get larger and heavier, improved stiffness or reliability is needed and currently that can only be enabled by composites or hybrids.”