Life cycle sustainability assessment of substituting fossil based with biogenic materials: A German case study on drinking cups and insulation boxes

Abstract

Bioeconomy is often cited as one pathway toward sustainable materials and a circular economy in an urban–rural context. This study conducts a life cycle sustainability assessment (LCSA)—life cycle assessment, social life cycle assessment, and life cycle costing (LCC)—to assess the benefits and impacts of substituting fossil polymer-based products with biogenic alternatives through two product systems: drinking cups and insulation boxes. In detail, we assess the environmental impacts, social hotspots, and societal costs subject to various product characteristics. The latter comprises, among others, different materials (fossil-based polymers, first-generation and second-generation biomass), allocation scenarios, electricity mixes, use cycles, and end-of-life (EoL) quotas. The LCSA is conducted with primary data provided by industry partners and secondary data from ecoinvent, the social hotspots database, and the literature. The results show that the drinking cup from second-generation bio-polyethylene (bio-PE) performs best in most environmental impact categories, followed by the fossil-based polypropylene (PP) cup. When substituting PP cups with bio-PE cups, 32% of CO₂ eq. emissions and 37% of water can be saved, while land use and particulate matter emissions increase by 37% and 7%, respectively. Due to low recycling rates in the status quo, cups made of polylactide acid—a first-generation bio-based polymer—often have higher environmental impacts than fossil-based ones. Governance and health and safety are the most prominent social categories and are especially linked with raw materials transportation. Similar trends are observed for the insulation box product system. The study identifies improvements in EoL practices, using biomass as-is, and regional sourcing as essential for enhancing bio-based materials' sustainability.