Best practices for comparative LCA of bio-based alternatives to fossil-based products

Abstract Purpose Substituting fossil-based products with bio-based alternatives is crucial for a sustainable bioeconomy. Comparative Life Cycle Assessment (LCA) studies can provide valuable guidance on when and how the substitution is environmentally sound. However, careful consideration of technical, regulatory, and economic conditions is needed when performing such LCA studies. The present work aims to identify the best practices for conducting a comparative LCA of bio-based products intended to substitute fossil alternatives in five sectors: construction, packaging, textiles, chemicals, and woodworking. Methods The study is based on two literature reviews, one focusing on the identification of the key challenges in the substitution, and the other reviewing several comparative LCA studies to assess to what extent those challenges were accounted for in the analysis. The findings are used to derive recommendations for multiple stakeholders, primarily for LCA practitioners. Results and discussion Our analysis shows that while some types of bio-based products exhibit the same technical characteristics as their fossil-based counterparts, others present technical differences as well as differences in durability, and availability. Moreover, bio-based materials frequently require compensatory measures to achieve the same technical performance, such as exterior coatings in packaging. Overlooking those challenges in the comparative LCA can lead to biased comparisons. Conclusions A thorough accounting of the specific contextual conditions is needed in LCA studies comparing bio-based products versus fossil-based counterparts. Specific recommendations for best LCA practice are provided, by ISO phase, e.g., a clear functional equivalence specification and ensuring that the system boundaries include all activities needed to compensate for differences in functionality. Further quantitative and qualitative research on how following these recommendations can influence the adoption of bio-based products over fossil counterparts is recommended as well.