Use of optimization tools for decision-making: Accounting for externalities in the production of biobased plastics

Plastic is one of the most versatile materials, but its production relies on fossil-based resources that have been linked to the increase in GHG emissions. In this sense, biobased plastics arise as an alternative to completely or partly substitute these fossil-based plastics. Nevertheless, it is still unclear if the use of biomass for the production of bioplastics can mitigate the environmental impact of fossil-based plastics and simultaneously provide economic benefits. The proper design of biomass supply chains plays an important role in the development of biobased plastics; however, economic criteria (e.g., maximization of revenues) is the most used parameter to optimize the supply chain, whereas environmental criteria are barely considered. For this purpose, we propose an optimization model that evaluates different supply chain configurations for the production of biobased polyethylene terephthalate (PET) using sugar beet and wheat. The optimization model accounts for the production costs and environmental costs through different methodologies, such as the Life Cycle Costing (LCC) and Life Cycle Assessment (LCA), respectively. We found that the production of biobased terephthalic acid (TPA) directly influences the economic profitability of 100% biobased PET. The selection of feedstock and carbon tax scenario play an important role in the development of biobased supply chains.