Plastics are on the rise to conquer every area of modern human life but lead to increased
pollution of nature enormous oil consumption and large-scale greenhouse gas emissions. Thus
to avoid climate change above 1.5¿C net-zero greenhouse gas emission plastics are needed by
the second half of this century. To reduce the greenhouse gas emissions associated with
plastics three circular technologies can be used: (1) chemical or mechanical recycling (2)
carbon capture and utilization and (3) biomass utilization. However current environmental
assessments of these circular technologies focus solely on individual or partly combined
circular technologies are limited to regional scopes and often apply inconsistent
methodologies. Thus it is currently unclear if net-zero emission plastics can actually be
achieved with the current set of circular technologies. Furthermore shifting from the linear
to a circular economy is regarded as energy-intensive and costly hindering strong policy
implementation from fostering the transition to a circular economy. To assess if net-zero
emission plastics can actually be achieved this thesis builds and uses the first global
industry-wide and systematic bottom-up model for plastics production and waste treatment
representing the global life cycle greenhouse gas emissions of 90% of global plastic
production. Using that model reveals that net-zero emission plastics can be achieved by
combining biomass and CO2 utilization with an effective recycling rate of 70% while saving up
to to 53% of energy and 288 billion USD compared to a fossil-based benchmark applying
large-scale carbon capture and storage. Achieving the full potential of energy and cost savings
while achieving netzero emissions requires the supply of biomass and CO2 at low cost while
cost of oil supply must be increased. To incentivize this shift investment barriers for all
available circular technologies have to be lowered by implementing consistent emission pricing
schemes using deposit systems for plastics to increase recyclability and stopping to subsidize
fossil resources. Thus this thesis shows that the greenhouse gas emission problem of plastics
can be solved with technologies and solutions already available today.
