Greenhouse gas (GHG) emissions need to be reduced to limit global warming. Plastic production requires carbon raw materials and energy that are associated today with predominantly fossil raw materials and fossil GHG emissions. Worldwide, the plastic demand is increasing annually by 4%. Recycling technologies can help save or reduce GHG emissions, but they require comparative assessment. Thus, we assess mechanical recycling, chemical recycling by means of pyrolysis and a consecutive, complementary combination of both concerning Global Warming Potential (GWP) [CO₂e], Cumulative Energy Demand (CED) [MJ/kg], carbon efficiency [%], and product costs [€] in a process‐oriented approach and within defined system boundaries. The developed techno‐economic and environmental assessment approach is demonstrated in a case study on recycling of separately collected mixed lightweight packaging (LWP) waste in Germany. In the recycling paths, the bulk materials polypropylene (PP), polyethylene (PE), polyvinylchloride (PVC), and polystyrene (PS) are assessed. The combined mechanical and chemical recycling (pyrolysis) of LWP waste shows considerable saving potentials in GWP (0.48 kg CO₂e/kg input), CED (13.32 MJ/kg input), and cost (0.14 €/kg input) and a 16% higher carbon efficiency compared to the baseline scenario with state‐of‐the‐art mechanical recycling in Germany. This leads to a combined recycling potential between 2.5 and 2.8 million metric tons/year that could keep between 0.8 and 2 million metric tons/year additionally in the (circular) economy instead of incinerating them. This would be sufficient to reach both EU and German recycling rate targets (EC 2018). This article met the requirements for a gold‐silver JIE data openness badge described at http://jie.click/badges.

Chemical recycling of complex plastic waste via pyrolysis can reduce fossil resource dependence of the plastics value chain and greenhouse gas emissions. However, economic viability is crucial for its implementation, especially considering challenging waste streams with high shares of engineering plastics that have lower pyrolysis product quality than standard thermoplastics waste. Thus, this study conducts a techno-economic assessment determining the profitability factors of pyrolysis plants for automotive plastic waste in Germany including different plant capacities and calculating cost-covering minimum sales prices for the resulting pyrolysis oil. Main findings are that due to economies of scale, the cost-covering minimum sales prices vary between 1182 €/Mg pyrolysis oil (3750 Mg input/year) and 418 €/Mg pyrolysis oil (100,000 Mg input/year). The pyrolysis technology employed must be robust and scalable to realize these economies of scale. Large plant capacities face challenges such as feedstock availability at reasonable costs, constant feedstock quality, and pyrolysis oil quality, affecting pyrolysis oil pricing. Due to the limited yield and quality of pyrolysis oil produced from these technically demanding feedstocks, policy implications are that additional revenue streams such as gate fees or subsidies that are essential to ensure a positive business case are necessary. Depending on the assessed plant capacity, additional revenues between 720 and 59 €/Mg pyrolysis oil should be realized to be competitive with the price of the reference product heavy fuel oil. Otherwise, the environmental potential of this technology cannot be exploited.

Most automotive plastic waste (APW) is landfilled or used in energy recovery as it is unsuitable for high‐quality product mechanical recycling. Chemical recycling via pyrolysis offers a pathway toward closing the material loop by handling this heterogeneous waste and providing feedstock for producing virgin plastics. This study compares chemical recycling and energy recovery scenarios for APW regarding climate change impact and cumulative energy demand (CED), assessing potential environmental advantages. In addition, an economic assessment is conducted. In contrast to other studies, the assessments are based on pyrolysis experiments conducted with an actual waste fraction. Mass balances and product composition are reported. The experimental data is combined with literature data for up‐ and downstream processes for the assessment. Chemical recycling shows a lower net climate change impact (0.57 to 0.64 kg CO ₂ e/kg waste input) and CED (3.38 to 4.41 MJ/kg waste input) than energy recovery (climate change impact: 1.17 to 1.25 kg CO ₂ e/kg waste input; CED: 6.94 to 7.97 MJ/kg waste input), while energy recovery performs better economically (net processing cost of −0.05 to −0.02€/kg waste input) compared to chemical recycling (0.05 to 0.08€/kg waste input). However, chemical recycling keeps carbon in the material cycle contributing to a circular economy and reducing the dependence on fossil feedstocks. Therefore, an increasing circularity of APW through chemical recycling shows a conflict between economic and environmental objectives.

A growing plastic production increases the pressure on waste management systems, which have to cope with greater volumes of plastic waste. Increased plastics recycling can reduce environmental impacts by lowering the need for primary plastics production and thus fossil resources demand. Current research is mainly focused on identifying environmentally friendly recycling technologies for different waste streams. However, recycling capacities must also be expanded to handle the waste generated. Therefore, this paper develops multiple exemplary multi-criteria optimization models to design an optimal recycling network. The models are deployed in a case study for plastic packaging waste in Europe for an advanced mechanical recycling process. We compare the different multi-criteria optimization approaches, how they balance environmental and economic aspects differently, and how this affects the recycling network design. Finally, we compare the optimization approaches and find goal programming the most promising approach for recycling network design that ensures a balance between economic and environmental objectives.

Global plastic production reached a new high in 2019. The high use of plastic leads to a high amount of plastic waste. Thereof, only 33% was collected for recycling in Europe. Plastic production depends on crude oil and energy and has high environmental impacts such as greenhouse gas emissions. The recycling of plastic waste can reduce dependency on fossil resources, help reduce environmental impacts, and achieve sustainability goals. Currently, the chemical recycling of plastic is discussed to complement the existing mechanical recycling. Comparing the recycling technologies is needed to identify and establish the most environmentally and economically promising technology for each waste stream. However, the quality of the recovered material has a high impact on assessment results. This study discusses different assessment metrics for recycling technologies concerning the influence of recovered materials’ quality by material substitution rates and circularity potential. In a case study, mechanical and chemical recycling via pyrolysis of HDPE from lightweight packaging waste from Germany is assessed. Mechanical recycling has a lower climate change impact than chemical recycling for material substitution rates above 0.85. On the other hand, chemical recycling has a higher potential to close the plastic loop and retain plastics within the economy due to the higher secondary material quality. The assessment allows evaluating recycling options for the considered plastics from the German collection systems for packaging.