Carbon footprint of plastic from biomass and recycled feedstock: methodological insights

Abstract

Purpose A circular (bio)economy is sustained through use of secondary raw material and biomass feedstock. In life cycle assessment (LCA), the approach applied to address the impact of these feedstocks is often unclear, in respect to both handling of the recycled content and End-of-Life recyclability and disposal. Further, the modelling approach adopted to account for land use change (LUC) and biogenic C effects is crucial to defining the impact of biobased commodities on global warming. Method We depart from state-of-the-art approaches proposed in literature and apply them to the case of non-biodegradable plastic products manufactured from alternative feedstock, focusing on selected polymers that can be made entirely from secondary raw material or biomass. We focus on global warming and the differences incurred by recycled content, recyclability, LUC, and carbon dynamics (effects of delayed emission of fossil C and temporary storage of biogenic C). To address the recycled content and recyclability, three formulas recently proposed are compared and discussed. Temporary storage of biogenic C is handled applying methods for dynamic accounting. LUC impacts are addressed by applying and comparing a biophysical, global equilibrium and a normative-based approach. These methods are applied to two case studies (rigid plastic for packaging and automotive applications) involving eight polymers. Results and discussion Drawing upon the results, secondary raw material is the feedstock with the lowest global warming impact overall. The results for biobased polymers, while promising in some cases (polybutylene succinate), are significantly affected by the formulas proposed to handle the recycled content and recyclability. We observe that some of the proposed formulas in their current form do not fully capture the effects associated with the biogenic nature of the material when this undergoes recycling and substitutes fossil materials. Furthermore, the way in which the recycled content is modelled is important for wastes already in-use. LUC factors derived with models providing a combined direct and indirect impact contribute with 15–30% of the overall life cycle impact, which in magnitude is comparable to the savings from temporary storage of biogenic C, when included. Conclusion End-of-Life formulas can be improved by addition of corrective terms accounting for the relative difference in disposal impacts between the recycled and market-substituted product. This affects the assessment of biobased materials. Inclusion of LUCs effects using economic/biophysical models in addition to (direct) LUC already embedded in commercial datasets may result in double-counting and should be done carefully. Dynamic assessment allows for detailed modelling of the carbon cycle, providing useful insights into the impact associated with biogenic C storage.

Environmental and Socioeconomic Impacts of Poly(ethylene terephthalate) (PET) Packaging Management Strategies in the EU

“…As recent studies have indicated that EU through recycling (of all) plastic waste could at most achieve an additional annual saving of ca. 14−20 Mt of CO 2 -eq, the savings from improved PET management could constitute a significant saving. Alternative VII also shows that the highest end-of-life recycling rate of PET packaging (including bottles, trays, flexible packaging, and strapping) could increase from the current 35% (2020) to 76% in 2030 (more precisely 90% for PET bottles and 70% for PET trays).…”

Bioplastics and Carbon-Based Sustainable Materials, Components, and Devices: Toward Green Electronics

“…A tremendous and continuously increasing amount of electronics waste that mankind is generating (∼54 MT in 2019) results in a massive quantity of mostly nonbiodegradable and potentially hazardous hard-to-recycle junk of polymers and metals. , An additional problem is the growing share of fossil resources in plastic production, which is proposed to increase to 20% (from the current 4–8%) of total oil consumption by the mid of this century. − As of today, only ∼10% of all plastics are synthesized from renewables, from which practically an insignificant fraction is applied by the electronics industry despite its overall 15% share in the use of all produced polymers. − The dielectric substrates of printed circuit boards (PCBs) are mostly made of epoxy and phenolic resins based on fossil feedstock that leave a large CO 2 footprint (5.7–7.6 kg CO 2 per kg) . While the currently used PCBs such as FR-4 and FR-2 show excellent electrical, mechanical, chemical, and thermal properties, there is a broad range of applications, in which mechanical flexibility and often optical transparency are necessary; thus, polyethylene terephthalate, polyether ether ketone, polyimide, and other thermoplastics are often applied.…”

Carbon Footprint of Landscape Tree Production in Korea

“…On the other hand, various studies related to the carbon footprint have been conducted in industrial fields such as building, civil engineering, and agriculture [17][18][19][20][21][22][23]. Gong and Shong (2016) quantified carbon emissions over the life cycle of buildings, including material production, construction, operation, and demolition, in Wuhan, China [17].…”

“…The carbon emissions were approximately 23.7 Mt, and the main factor in carbon emissions was energy consumption from building operation. Studies calculating the carbon emissions of building materials production or operation have also been conducted [18][19][20][21]. Sambito and Freni (2017) estimated the carbon footprint of the integrated urban water system in Palermo, Italy, and proposed replacing old pumps with high-efficiency ones to reduce carbon emissions [22].…”