Circular Strategies for End-of-Life Wind Turbine Blades: A Review of Technical, Environmental, Economic and Regulatory Perspectives

The increasing deployment and decommissioning of wind turbines (WTs) generates growing end-of-life (EoL) wind turbine blade (WTB) material streams for which no single circular pathway is suitable. This structured narrative review applies an adapted R-strategy framework to systematically compare circular WTB management options from R9 Recover to R1/R2 Rethink/Reduce. Technical processes and implementation conditions are synthesized together with environmental, economic, technological, and regulatory evidence. The review shows that strategies preserving the original product or component, including reuse, repair/refurbishment, and repurposing, retain substantial structural and manufacturing value but depend strongly on WTB condition, geometry, logistics, and qualification requirements. Recycling provides scalable material-oriented pathways, although suitability differs markedly between glass fiber-reinforced polymers (GFRPs) and carbon fiber-reinforced polymers (CFRPs): mechanical recycling and co-processing remain particularly relevant for GFRPs, whereas thermal and chemical recovery offer greater potential for CFRPs. Environmental and economic performance therefore cannot be inferred solely from the R-hierarchy. Based on these findings, the review derives stakeholder-specific recommendations for industry, operators, policymakers, and research to support condition-based pathway selection, cascading R-strategies, standardized qualification, supportive legislation, and circular WTB design.