NREL Builds and Tests Wind Turbine Blade With Recyclable Resin

Researchers at the Department of Energy’s National Renewable Energy Laboratory (NREL) published a paper in the journal Science describing the manufacture and testing of a composite wind turbine blade using a resin that is chemically recyclable and made from materials that can be bio-derived.

The new resin, nicknamed PECAN (polyester covalently adaptable network) performs on par with the current industry standard of blades made from a thermoset resin and outperforms certain thermoplastic resins intended to be recyclable.

Cubes of the PECAN resin developed by NREL, made from bio-derivable sugars. Source: Werner Slocum, NREL.

Using incumbent technology, wind blades last about 20 years, and afterward they can be landfilled or shredded for use as concrete filler. The PECAN resin enables blades to be recycled using heat and methanol, producing materials that could be reused to manufacture new blades.

“It is truly a limitless approach if it’s done right,” says Ryan Clarke, postdoctoral researcher at NREL and first author of the paper. Clarke says the chemical recycling process was able to break down the 9-m prototype blade in about 6 hours.

“Nine meters is a scale that we were able to demonstrate all of the same manufacturing processes that would be used at the 60-, 80-, 100-meter blade scale,” says Robynne Murray, also an author on the paper.

Composites made from the PECAN resin held their shape, withstood accelerated weatherization validation and could be made within a time frame similar to the existing cure cycle for how wind turbine blades are currently manufactured.

The work was conducted by investigators at five NREL research hubs, including the National Wind Technology Center and the BOTTLE Consortium. The researchers demonstrated an end-of-life strategy for the PECAN blades and proposed recovery and reuse strategies for each component.

“The PECAN method for developing recyclable wind turbine blades is a critically important step in our efforts to foster a circular economy for energy materials,” says Johney Green, NREL’s associate laboratory director for Mechanical and Thermal Engineering Sciences.