Standing hundreds of feet above ground, wind turbines—like tall trees, buildings, and telephone poles—are easy targets for lightning. Just by virtue of their height, they will get struck.
Lightning protection systems exist for conventional wind turbine blades. But protection was needed for blades made from a new type of material—thermoplastic resin composites—and manufactured using an innovative thermal (heat-based) welding process developed by scientists at the National Renewable Energy Laboratory (NREL).
Thermoplastic materials, like plastic bottles, can be more easily recycled than the thermoset materials commonly used to make wind turbine blades today. While thermoset materials need to be heated to cure, thermoplastics cure at room temperature, which reduces both blade manufacturing times and costs.
NREL’s patent-pending thermal welding process for thermoplastic blades allows for these benefits and even adds to them by replacing the adhesives currently used to bond blade components. The use of welding instead of adhesives eliminates the downsides of added weight and cracking potential.
While thermal welding offers benefits, it also requires adding within the blade a metal heating element—which can attract lightning. As a result, a team of NREL researchers led by Robynne Murray and supported by General Electric (GE) and LM Wind Power (a GE subsidiary) invented a new lightning protection system to keep the novel thermoplastic materials safe.
10 August 2021