Evaluating Circular Economy Scenarios for Automobile Polystyrene Prototypes Using a Comparative Life Cycle Assessment

Abstract Polystyrene prototypes are used during the vehicle design phase for a few weeks and then discarded, despite their high circularity potential. However, no Life Cycle Assessment (LCA) or analysis of eco-design strategies utilising this circularity potential exists. Our study aims to address this gap and compare two conventional models with three circularity-oriented eco-design scenarios to evaluate their environmental benefits and advise prototyping companies on circular economy (CE) strategies. Using OpenLCA software and the Ecoinvent 3.8 database, an attributional cradle-to-grave LCA was conducted following ISO 14040/44 standards, based on primary data from a French prototype producer. Five automobile polystyrene prototype scenarios were modelled: two conventional (five-door and three-door car models) and three eco-design proposals (using production wastes, re-using an undercarriage and remanufacturing a complete prototype after usage). Our findings indicate that the three eco-design proposals, inspired by the 9Rs principles, effectively target the conventional models’ hotspots. Each proposal demonstrates a lower environmental impact across all life cycle phases and impact categories compared to the conventional models, with the remanufacturing option showing the most significant improvements. For example, the impact on climate change decreased by 36% when using production waste, 12% when re-using an undercarriage and 83% when using complete remanufacturing. We recommend that prototyping companies apply these three eco-design proposals, prioritising the remanufacturing option, to capitalise on automobile polystyrene prototypes’ circularity potential. This study will enrich the scientific literature with results obtained from primary data collected at a company site and help companies in their decision-making process to integrate CE principles.