Josey Centennial Professor in Energy Resources The University of Texas at Austin
While most plastics used today in the US are compatible with recycling processes, only around 9% are actually recycled. Instead, the majority of plastics settle in our landfills, waterways, and environment. Plastics are generally made of fossil fuels and do not degrade quickly, which means their use, especially single-use, is energy intensive and impactful on the environment. Thus, we hypothesize that reusing or upcycling plastics that would otherwise need to be landfilled might also avoid water use, energy consumption, and emissions. Through the guidance, mentorship, and funding of the NSF Convergence Accelerator Program, we will test this hypothesis by investigating the energy, water, and emissions tradeoffs of 3D printing (i.e., additive manufacturing) using plastic waste, such as single use water bottles or plastic containers. In this study, fused granular fabrication (FGF), which uses flakes or pellets ground from plastic waste as feedstock, is compared to a) conventional fused deposition modeling (FDM) 3D printing which uses filament for printing and b) injection molding (IM) which represents a more traditional high volume manufacturing process. To compare these processes, a detailed ‘cradle to gate’ Life Cycle Assessment (LCA)—using OpenLCA software with the Ecoinvent database—of each approach is performed with the goal of printing useful and durable home goods such as stools or small shelves, among other potential options. In addition, sensitivity analyses exploring the water, energy, and emissions impacts of extended or different supply chain transportation routes, various material inputs (e.g., virgin vs. recycled filament for traditional FDM 3D printing and different types of plastics compatible with 3D printing), and electricity mixes are performed and evaluated.
