Environmental Sustainability Assessment of Hydrogen from Waste Polymers

[Image: see text] The rising demand for single-use polymers calls for alternative waste treatment pathways to ensure a circular economy. Here, we explore hydrogen production from waste polymer gasification (wPG) to reduce the environmental impacts of plastic incineration and landfilling while generating a valuable product. We assess the carbon footprint of 13 H(2) production routes and their environmental sustainability relative to the planetary boundaries (PBs) defined for seven Earth-system processes, covering H(2) from waste polymers (wP; polyethylene, polypropylene, and polystyrene), and a set of benchmark technologies including H(2) from natural gas, biomass, and water splitting. Our results show that wPG coupled with carbon capture and storage (CCS) could reduce the climate change impact of fossil-based and most electrolytic routes. Moreover, due to the high price of wP, wPG would be more expensive than its fossil- and biomass-based analogs but cheaper than the electrolytic routes. The absolute environmental sustainability assessment (AESA) revealed that all pathways would transgress at least one downscaled PB, yet a portfolio was identified where the current global H(2) demand could be met without transgressing any of the studied PBs, which indicates that H(2) from plastics could play a role until chemical recycling technologies reach a sufficient maturity level.