End-of-life wind turbine blades as a resource: A comparative study of pyrolysis and combustion

The transition to a low-carbon economy has accelerated wind energy installations. However, managing waste wind turbine blades (WTBs) remains a challenge due to their composite nature and limited regulations. This study explores the thermochemical recovery of WTBs via pyrolysis and combustion, focusing on gaseous emissions, pyrolysis oil, pyrochar morphology and ash. WTBs exhibit low carbon content (29.5 wt%), a heating value of 12 MJ/kg, and high ash content (58 wt%), meeting the minimum fuel threshold for cement production but not EN 15359 standards. Pyrolysis tests revealed decomposition behavior (T_onset: 348 °C, T_peak: 390 °C, T_offset:421 °C) with a 39.3 % conversion rate. TG-FTIR analysis identified alcohols, esters, phenolics, and carbonyl groups, with key volatiles released at 366–417 °C. Pyrolysis oil (C6-C40, dominated by C15) was rich in Bisphenol A derivatives, suitable for resin production. Pyrochar, primarily glass fiber, exhibited low carbon content, making it suitable as a concrete or polymer additive. Combustion tests showed a mean ignition temperature of 276 °C, burnout at 686.5 °C, and moderate combustibility index. CO₂ emissions peaked between 421 and 572 °C. Ash morphology revealed glass fibers surrounded by loosely adherent ash. These findings support WTB valorization, promoting energy and material recovery while addressing environmental concerns.