Abstract
Wind energy offers a low emission source of energy while also being among the cheapest forms of electricity generation in the United States. While most materials in a wind turbine can be recycled at the end of their life, large composite blades are often treated as waste, leading to potential strains on regional landfills, a loss of durable materials, and forfeiture of embodied energy. Numerous approaches exist for recycling composite wind blades at various levels of technological and commercial maturity. This study uses life cycle assessment to compare several promising recycling approaches as well as understand trade-offs between net greenhouse gas emissions and operational costs. Results include considerations for processing current glass-fiber blades with thermoset epoxy, upcoming decommissioned blades with carbon-fiber spar caps, and future blades constructed with recyclable resin systems. The optimal recycling processes for current glass-fiber blades are those with minimal processing emissions and costs, which are necessary to compete with the low costs and emissions associated with virgin glass-fiber production. For material streams with carbon fiber, the optimal processes are those that recover the highest-quality fiber, therefore recovering the largest possible portion of embodied emissions and high costs of carbon fiber. The results for recyclable resin systems are less certain but do reveal that these resins can reduce net greenhouse gas emissions and material waste from chemical recycling processes. These and other results display a promising future for wind turbine blade recycling, including many paths to further develop recycling technologies while increasing circularity, reducing emissions, and lowering operating costs.