Investment risk assessment of wind turbine blade pyrolysis project based on improved weighted hesitant fuzzy set and aggregation operator

Pyrolysis is considered as a potential method for the treatment of disused wind turbine blades. However, existing relevant researches mainly focus on the laboratory-scale experimental studies and technology development, neglecting risk assessment for wind turbine blade pyrolysis (WTBP) projects using Multi-criteria Decision-making (MCDM) methods. Herein, this paper presents a novel investment risk assessment framework for WTBP based on improved Weighted Hesitant Fuzzy Sets (WHFSs). A new aggregation operator is proposed that enhances stability and reduces computational complexity, making it more suitable for the uncertain and complex nature of WTBP projects risk information. Firstly, a comprehensive criteria system conforming to the characteristics of WTBP was established from multiple aspects. Secondly, to solve the intermittent failure of the existing score function, a more stable score function of the WHFEs was proposed to describe the criteria's information. Thirdly, we applied the DEMATEL method in an adapted way to capture the influence structure among expert judgments, rather than interpersonal relationships. Although DEMATEL is typically used to analyze relationships between evaluation criteria, this study applies DEMATEL to construct an influence matrix reflecting how the expert judgments shape the overall evaluation. This adaptation acknowledges that in complex, multi-expert contexts such as WTBP projects evaluation, expert judgments may not be entirely independent. Fourthly, the aggregation operator was used to obtain the risk value of the project. Finally, taking Shandong Province of China as an example, the reliability of the framework was verified.