Designing novel bioplastics and their supply chains within planetary boundaries

Biomass is a promising renewable feedstock for the chemical industry, yet current processes that retrofit biobased molecules into petrochemicals suffer from low biomass utilization efficiency, limiting environmental sustainability and exacerbating pressures on biodiversity, water, and land resources. Recent developments in alternative bioplastics that mimic the properties of PET—the primary plastic used in packaging—aim to address these issues by retaining as many biogenic atoms as possible in native-like structures. To guide the formulation of these new products, we assess the prospective environmental impacts of PET-replacement bioplastics and propose design targets to minimise the transgression of the planetary boundaries (PB). We integrate biorefinery process models, and their supply chains, into a continent-wide energy system model, which includes a blueprint of Europe's industrial sector, to analyse resource competition between biorefineries and the existing industry. To prevent shifting environmental burdens, we conduct a holistic environmental impact assessment by mapping 16 mid-point indicators of the Environmental Footprint method to PBs, downscaled to the European industry with various socio-economic methods. For novel bioplastics, a one-to-one mass substitution with petrochemical counterparts may not be feasible. The environmental impacts of new molecules must be evaluated considering use-phase functions, which depend on tuneable material properties such as gas and water resistance and mechanical strength. Preliminary results indicate that while the novel bioplastics significantly reduce contributions to climate change, they may disrupt the freshwater cycle if increased electricity demand is met primarily through hydropower. Optimizing energy systems in synergy with production supply chains offers pathways for a future European chemical industry that aligns with both environmental and societal constraints.