(160c) Cost-Effective Strategies Towards Net-Zero Plastic Packaging Based on a Resilient and Sustainable Circular Economy

Plastics constitute 80% of all carbonaceous chemical products and have the highest growth rate of all bulk materials, with global production reaching 400.3 MMT in 2022. Major sectors driving plastic demand include packaging, transportation, construction, electronics, consumer goods, machinery, and textiles. The production of plastics contributes significantly to greenhouse gas (GHG) emissions, estimated at 1.34 gigatonnes per year, primarily due to fossil resource consumption and inadequate recycling practices. Action on packaging should be prioritized as it comprises 37% of total plastic production, and since their short lifespan leads to substantial waste generation annually. Thus, addressing the fossil resource consumption and inadequate recycling practices associated with plastic packaging, represents a crucial opportunity to enable the net-zero transition of the carbon economy.

The technologies currently employed for manufacture of plastic packaging are dominantly fossil-based and the business models are not focused on waste recovery at the end-of-life of the products. Thus, emerging low-emission value-chain alternatives can significantly reduce the carbon footprint of the products. Their deployment however, is hindered by substantial capital investments and potentially higher operational costs. Consequently, meticulous planning to steer the plastic packaging economy towards achieving net-zero carbon emissions becomes imperative to guide decision-makers in making cost-effective investment decisions.

Prior research has focused on pathways to net-zero chemicals and plastics [1-3]. However, these studies have utilized aggregated models for plastics production and recycling, which might not be applicable for a multitude of end-use sectors. For example, the feasibility of mechanical recycling depends on chemical composition and quality of the plastic waste. Multilayer plastic films are one such packaging product which require alternative techniques for resin recycling beyond mechanical means such as the Solvent Targeted Recovery and Precipitation (STRAP) process, due to their heterogeneous chemical structure. In our investigation, we aim to address this gap by offering a more granular examination of technologies specific to the production and recovery of different types of plastic packaging.

Furthermore, prior research has predominantly focused on commercially available alternative technologies, neglecting the potential of options with lower technology readiness level (TRL) [1-3]. We address this gap by incorporating the evolution of technological innovations over time, with the goal of reaching an adoptable point characterized by the maximum TRL. In essence, our approach also accounts for the Research and Development (R&D) expenses associated with the scaleup of low TRL technologies, in addition to capital and operational costs. Thus, we project a realistic and holistic roadmap encompassing the possible bottlenecks towards a net-zero packaging industry.

Additionally, the current literature in the area uses commercial life-cycle inventories and costing datasets for their analyses, thereby hindering further dissemination behind steep paywalls. In contrast, our approach involves leveraging a publicly accessible database of the chemical industry developed by us earlier [5]. Our objective is to enhance transparency and accessibility by making all models and associated data openly available to the public since this is needed to jump start research to enable the urgent transition toward net-zero.

Our analysis indicates the infeasibility of current technologies to form a net-zero value chain for packaging. We therefore design cost-effective roadmaps for some future scenarios. The minimum emission value-chain for the BAU case serves as the baseline for our model, representing the continuation of current practices without significant technological interventions. The scenario for “Current Opportunity” makes commercially viable low-emission technologies available in the superstructure network. Investment decisions dictate the adoption of these technologies as needed. The scenario for “Future Opportunity” allows the scale-up of technologies at all value chain stages and TRLs, subject to the R&D costs and investment decisions.

This re-design of the packaging economy must ensure resilience and overall sustainability of the value chains. Potentially perverse solutions which are unendurable in the longer term, such as endless CCS and land-filling may be chosen as the primary value chain decisions, unless otherwise constrained. Moreover, cost-effective low emission technologies often shift environmental impact beyond metrics of immediate interest. We constrain the allowable biodiversity loss, water consumption, and land use to avoid such results.

In addition to prioritizing environmental sustainability, ensuring the resilience of packaging value chains is imperative. A resilient economy is characterized by its ability to withstand and adapt to disruptions, thereby preventing system collapse. For example, incorporating multiple technological options for waste treatment ensures that the system remains capable of waste recovery in the face of disruption to certain pathways. To assess the resilience of the economic network, we employ ecological resilience principles derived from Ecological Network Analysis (ENA).

We apply a multi-period optimization problem, developed for roadmapping to a net-zero chemical industry, to the packaging industry. We introduce additional constraints to ensure durable, resilient, and sustainable solutions. Our proposed methodology involves the generation of the following three roadmaps, each tailored to address the unique challenges and opportunities within the plastic packaging industry:

(1) Cost-effective transition solutions to achieve net-zero by 2050:

This roadmap prioritizes minimizing costs to achieve net-zero greenhouse gas (GHG) emissions by 2050. It does not consider constraints related to landfilling, Carbon Capture and Storage (CCS), circularity, sustainability, or resilience. The primary focus is solely on achieving a net-zero economy by 2050 without necessarily ensuring durable, sustainable, and resilient solutions for the plastic packaging supply chain.

(2) Cost-effective long-term solutions to achieve net-zero by 2050:

This roadmap aims to identify investment decisions necessary for achieving long-term net-zero solutions for plastic packaging. By imposing constraints on landfilling and addressing limitations associated with CCS, the goal is to develop solutions that are durable and capable of mitigating carbon emissions by and beyond 2050. Circularity constraints are also enforced, recognizing the finite nature of fossil resources and the importance of promoting circularity in the long term.

(3) Cost-effective long-term solutions to achieve a sustainable and resilient net-zero economy by 2050:

This roadmap outlines a path towards achieving a net-zero, sustainable, and resilient circular economy for plastic packaging. In addition to imposing constraints related to durable solutions, such as those discussed in the previous roadmap solution, this approach also incorporates constraints regarding environmental sustainability and supply chain resilience. For environmental sustainability, constraints are placed on other environmental impacts to ensure a net-zero impact across all environmental aspects, not just CO2 emissions. For resilience, a constraint is applied based on the value of ecological resilience calculated for the network, aligning with the concept of the "window of vitality" associated with resilient ecosystems [6].

Our initial findings show that a net-zero solution using the portfolio of current technologies is not feasible. Therefore, investing in innovation is necessary to achieve this goal. We see potential in both the current opportunity and future opportunity scenarios to create roadmapping solutions for both short and long-term planning. These scenarios reveal the large potential of innovative approaches for end-of-life treatment of materials, including mechanical, solvent-based, and chemical recycling to accelerate towards the goal. Additionally, the contribution of low-TRL solutions such as electrification of the industry to achieve cost-effective long-term net-zero solutions was captured. Bio-based technologies are shown to play a central role in achieving long-term sustainability. However, careful considerations are necessary to prevent environmental burden shifts, particularly regarding the high energy and water consumption of bio-based technologies and the potential conflicts deriving from the land required for biomass cultivation.

Reference:

[1] Stegmann, P., Daioglou, V., Londo, M., van Vuuren, D. P., & Junginger, M. (2022). Plastic futures and their CO2 emissions. Nature, 612(7939), 272-276.

[2] Stegmann, P., Daioglou, V., Londo, M., & Junginger, M. (2022). The plastics integrated assessment model (PLAIA): Assessing emission mitigation pathways and circular economy strategies for the plastics sector. MethodsX, 9, 101666.

[3] Zibunas, C., Meys, R., Kätelhön, A., & Bardow, A. (2022). Cost-optimal pathways towards net-zero chemicals and plastics based on a circular carbon economy. Computers & Chemical Engineering, 162, 107798.

[4] Meys, R., Kätelhön, A., Bachmann, M., Winter, B., Zibunas, C., Suh, S., & Bardow, A. (2021). Achieving net-zero greenhouse gas emission plastics by a circular carbon economy. Science, 374(6563), 71-76.

[5] Sen, A., Bakshi, B., Stephanopoulos, G. (Under Preparation). An open access network model of the global chemicals and materials industry towards systems analysis and design

[6] Chatterjee, A., & Layton, A. (2020). Mimicking nature for resilient resource and infrastructure network design. Reliability Engineering & System Safety, 204, 107142.