Decarbonizing Polyethylene Terephthalate Production Using Electrified Boilers, Clean Fuel Alternatives, and Low-Carbon Feedstocks

Polyethylene terephthalate (PET) is a prominent plastic polymer known for its significant growth rates in recent decades, and it is utilized in nearly every aspect of daily life, particularly in textiles and for water bottles. PET resin demand is expected to increase from 25 million tonnes to 61 million tonnes between 2019 and 2060, and subsequent greenhouse gas (GHG) emissions are expected to peak from 42.25 million tonnes to 103.09 million tonnes of CO2 equivalent. The carbon neutrality in PET production is anchored mainly on two fronts: shifting from traditional fossil-based boilers to renewable alternatives, such as renewable natural gas or electric boilers, and low-carbon feedstocks based on biomass and carbon capture and utilization (CCU). This study investigates the emission intensities of these mitigation measures, leveraging a life cycle assessment of the production stage. The analysis underscores the importance of solar-electrified boilers, which can reduce emissions by 12%. On the other hand, the GHG reduction potential of biobased feedstocks depends on the specific pathway through which they are produced. For example, bioparaxylene made from isobutanol derived from ammonia fiber explosion corn stover can significantly reduce GHG emissions, while that made from isobutanol sourced from dilute acid pretreatment may increase business-as-usual emissions. Furthermore, recent innovations in CCU can significantly reduce GHG emissions. The production of ethanol from CO2 can achieve a 37% decrease in GHG emissions, while the electrochemical reduction of CO2 to produce ethylene for PET manufacturing results in a 66% decrease in GHG emissions.