We have all seen the photos of retired wind blades in landfills, painting a powerful picture for those concerned with the environment and with energy production for the future. Researchers at the National Renewable Energy Laboratory (NREL), with funding from the U.S. Department of Energy’s Advanced Manufacturing Office, are taking on this challenge and moving forward with work to additively manufacture wind turbine blades using recyclable thermoplastics.
The NREL team worked with the Institute for Advanced Composites Manufacturing Innovation (IACMI) in NREL’s Composites Manufacturing Education and Technology (CoMET) Facility to develop a new process to build lighter, longer, more efficient, more sustainable, and less costly wind blades. The new process is a radical change from the traditional production process of wind turbine blades which is typically a clamshell design of two fiberglass blade skins and thermoset resin materials bonded with adhesives and stiffened with shear webs. The new blades are designed relying on a thermal welding process that eliminates the adhesives, allowing for better recyclability as the thermoplastics can be heated at the end-of-life to separate the original polymers. Design work using 3D printing will allow the team to evaluate new and innovative structural plans.
Derek Berry, NREL senior wind technology engineer, explained, “Once you produce a blade with a thermoset resin system, you cannot reverse the process. That makes the blade difficult to recycle. With two thermoplastic blade components, you have the ability to bring them together and, through the application of heat and pressure, join them. You cannot do that with thermoset materials.”
Plans include NREL’s continued collaboration with partners IACMI, TPI Composites, Additive Engineering Solutions, Ingersoll Machine Tools, and Vanderbilt University to develop blade core structures more than 100 meters in length with both weight and cost reduced by 10% or more and cycle time reduced by at least 15%.