Critical aspects in the life cycle assessment (LCA) of bio-based materials – Reviewing methodologies and deriving recommendations

Concerns over non-renewable fossil fuel supply and accelerated climate change have been driving the Renaissance of bio-based materials. To substantiate environmental claims, the impacts of bio-based materials are typically quantified by applying life cycle assessment (LCA). The internationally agreed LCA standards provide generic recommendations on how to evaluate the environmental impacts of products and services but do not address details that are specifically relevant for the life cycles of bio-based materials. Here, we provide an overview of key issues and methodologies explicitly pertinent to the LCA of bio-based materials. We argue that the treatment of biogenic carbon storage is critical for quantifying the greenhouse gas emissions of bio-based materials in comparison with petrochemical materials. We acknowledge that biogenic carbon storage remains controversial but recommend accounting for it, depending on product-specific life cycles and the likely time duration of carbon storage. If carbon storage is considered, co-product allocation is nontrivial and should be chosen with care to avoid double counting of stored carbon in co-products. Land-use change as well as the land use-related, soil degradation, water use, and impacts on soil carbon stocks and biodiversity are important aspects that have recently received attention. We explain various approaches to account for these and conclude that substantial methodological progress is necessary, which is however hampered by the complex and often case-specific and site-specific nature of impacts. With the exception of soil degradation, we recommend preliminary approaches for including these impacts in the LCA of bio-based materials. The use of attributional versus consequential LCA approaches is particularly relevant for in the context of bio-based materials. We conclude that it is clearly more challenging to prepare accurate consequential LCA studies, especially because they should ideally account for future developments and secondary impacts around bio-based materials which are generally difficult to anticipate and quantify. Although hampered by complexity and limited data availability, application of the proposed methodological approaches to the extent possible would allow obtaining a more comprehensive insight into the environmental impacts of the production, use, and disposal of bio-based materials.
JRC.F.8-Sustainable Transport