A team of National Renewable Energy Laboratory (NREL) researchers are furthering their revolutionary combination of recyclable thermoplastics and additive manufacturing to manufacture advanced wind turbine blades.
The advance was made possible by funding from the U.S. Department of Energy’s Advanced Manufacturing Office—awards designed to stimulate technology innovation, improve the energy productivity of American manufacturing, and enable the manufacturing of cutting-edge products in the United States.
Led by NREL senior wind technology engineer Derek Berry, the team’s novel techniques could revolutionize how wind turbine blades are manufactured.Related Read: Growing Role of Polymers and Plastics Used in Renewable Energy Sector
Rethinking the Conventional Design
Today, most utility-scale wind turbine blades have the same clamshell design: Two fiberglass blade skins are bonded together with adhesive and use one or several composite stiffening components called shear webs. This manufacturing process has been optimized for efficiency over the past 25 years—but it has changed very little. That needs to change.
To make wind turbine blades lighter, longer, less expensive, and more efficient at capturing wind energy—improvements critical to the Biden Administration’s goal to cut greenhouse gas emissions in part by increasing wind energy production—researchers must entirely rethink the conventional clamshell.
To start, the NREL team is focusing on the resin matrix material. Current designs rely on thermoset resin systems like epoxies, polyesters, and vinyl esters, polymers that, once cured, cross-link like brambles.
"Once you produce a blade with a thermoset resin system, you cannot reverse the process
," Berry said. "That makes the blade difficult to recycle
." As more and more wind turbines are installed every year, new wind turbine blades should be designed to be repurposed or even recycled to prevent them from undercutting the green economy they are meant to help build.
Enabling End-of-Life Recyclability
Derek Berry and his team of NREL researchers did just that. Working with the Institute for Advanced Composites Manufacturing Innovation in NREL’s Composites Manufacturing Education and Technology (CoMET) Facility, the multi-institution team developed systems that use thermoplastics, which, unlike thermoset materials, can be heated to separate the original polymers, enabling end-of-life recyclability.
Thermoplastic blade parts can also be joined using a thermal welding process that could eliminate the need for adhesives—often heavy and expensive materials—further enhancing blade recyclability.
"With two thermoplastic blade components, you have the ability to bring them together and, through the application of heat and pressure, join them
," Berry said. "You cannot do that with thermoset materials
Moving forward, NREL, along with project partners TPI Composites, Additive Engineering Solutions, Ingersoll Machine Tools, Vanderbilt University, and the Institute for Advanced Composites Manufacturing Innovation, will develop innovative blade core structures to enable the cost-efficient production of high-performance, very long blades—well over 100 meters in length—that are relatively low weight.Source: NREL