How much does the recycling and regeneration of waste plastics reduce emissions?
In daily life, we often see recycled PET bottles labeled with carbon emission reductions when made into clothing. Society advocates for the public to engage in garbage recycling, as it not only reduces waste but is also seen as having the effect of reducing emissions.
With the gradual advancement of the dual carbon target, the reduction of emissions that can be achieved through circular economy and plastic recycling products has become a key focus for enterprises. This not only affects recycling and regeneration enterprises, but also has an impact on brand enterprises and even upstream polymer companies.
The recycling and reuse of waste plastics not only reduces the impact of waste on the environment, but also allows resources to be reused as raw materials, replacing the demand for new materials, which is closely related to the carbon emissions of products.
In 2019, the journal Nature Climate Change published an article titled "Strategies for Reducing the Global Carbon Footprint of Plastics". The article mentions that in 2015, the global lifecycle greenhouse gas emissions of traditional plastics were 1.8 billion tons of CO2 equivalent (CO2e), accounting for 4.5% of global greenhouse gas emissions. According to current trends, the carbon emissions from plastics will climb to 6.5 billion tons by 2050, reaching 15% of the global carbon budget.
1. Ways to reduce carbon emissions from products
The demand for sustainable products in the international community continues to grow, especially in order to achieve carbon neutrality goals. The supply chain plays a key role in achieving product carbon neutrality, especially in the consumer industry where it accounts for over 80% of products. Sustainable products will be a focus of attention for the European Union, as reflected in the "Ecological Product Sustainable Design Regulation" (ESPR) passed in 2024.
The definition of sustainable products is based on the perspective of the entire lifecycle, covering the entire process from the raw materials of the product to its disposal and recycling.
1) Recycling method
The recycling method can be divided into two situations, one is the waste mode, which refers to the conventional baseline scenario, that is, setting the situation where there is no recycling and the waste plastic is discarded as the benchmark. Another type refers to the existence of recycling, which includes two stages: the recycling stage and the regeneration stage. The recycling stage refers to the process in which relevant personnel or individuals recycle waste plastics used in fishing or agricultural production processes, or generated during consumption processes, to prevent these wastes from entering the ocean or environment. The recycling stage refers to the transportation of waste plastics from recycling facilities to recycling enterprises, where they undergo classification, cleaning, and are produced into recycled raw materials through recycling processes.
2) Emission reduction methods
Regarding the carbon reduction methods of products, one is to use bio based materials instead of fossil fuel based materials, the other is to use more renewable materials to replace new materials, and the third is to use renewable energy. The 2019 article mentioned earlier also indicates that the regeneration of biobased materials can reduce emissions, but it cannot compare to the emission reductions achieved by general plastic recycling. Renewable energy remains an important source of emissions reduction.
The carbon reduction of products is partly achieved through the regeneration or substitution of raw materials used in the products. On the other hand, it is because the products are recycled, thus avoiding the consequences of incineration or landfilling. The carbon emissions of these products themselves cannot be reduced, but their disposal stage can avoid carbon emissions caused by landfilling or incineration through recycling, which is called "emission avoidance". However, this avoidance of emissions belongs to the later stages of product life cycle use and disposal, and is currently generally not included in the calculation of carbon emissions in the supply chain of enterprises.
2. Product carbon emission reduction accounting
In 2023, we developed a group standard for carbon reduction calculation of plastic packaging substitute materials - the "T/ACEF 060-2023 Carbon Reduction Accounting Criteria for Plastic Packaging Substitute Materials"; In 2024, another group standard was issued - the "T/ACEF131-2024 Guidelines for Traceability and Carbon Reduction Accounting of Marine Fishing Waste Plastic Recycling". These two standards provide detailed regulations on the recycling methods, application conditions, traceability requirements, and carbon reduction accounting processes for plastic packaging alternatives and marine fishing waste plastics.
When calculating the carbon reduction of recycled products, the first step is to clarify the baseline scenario. The baseline scenario refers to new material products that have not undergone recycling and regeneration processes. What we need to determine is the difference between the different emission reduction methods used in the recycling process and the conventional ones without recycling and regeneration processes. These emission reductions need to be calculated, especially with clear boundaries for recycling (project boundaries). If the emissions from the recycling process are greater than those from the raw material production process, then there will be no emission reduction effect.
The carbon emission reduction of recycled plastics consists of three parts: the first part is to compare the carbon emission difference between the behavior of recycling waste plastics and the corresponding baseline waste behavior, that is, to avoid emissions; The second part is the carbon emissions between using waste plastics to manufacture recycled materials and replacing the same weight of new materials; The third part is the additional carbon emissions generated during the regeneration process. The final product carbon reduction is the sum of the first and second parts minus the third part.
The difference in carbon emissions between recycled products and new materials is only in the carbon emissions consumed in the production of raw materials. The process of producing plastic products is the same and does not need to be recalculated throughout the entire lifecycle, while the process of waste disposal in the backend is different.
From this, it can be seen that the carbon emissions of raw materials include the process from mining to manufacturing, while the carbon emissions of recycled materials no longer need to include the production stage of raw materials, but should cover the collection, classification, cleaning, crushing, cleaning, washing, and drying of recycled materials. Secondly, the recycling of plastics is about reducing emissions from product materials, based on a comparison of carbon footprints. Overall, the recycling process still generates carbon emissions. Furthermore, if the substitute materials include various materials such as paper, glass, biodegradable plastics, as well as different types and proportions of plastic recycled materials such as PET, PP, PE, etc., they can all be calculated based on this calculation principle. Specific accounting formulas are provided in both standard texts. For the emission factors (EF) of different materials, due to the lack of relevant data in China, international literature data or website data from authoritative institutions are generally used.
According to the research results of British scholars, the carbon footprint of a 16.6g recycled PET tray is 23.42g CO2e. Making a tray with 85% recycled content has a carbon footprint that is 60% lower than the benchmark for using virgin materials. If the waste recycling rate is increased from 22.5% to 32%, the carbon footprint will be reduced by 2%. We take packaging containing 30% recycled PET as an example in the standard appendix and calculate a carbon reduction of 1.473 tons per ton of PET, which is equivalent to 62% of the carbon emissions from new materials, or a reduction of 38%. This lays the foundation for the subsequent work on carbon emission reduction labels for recycled products.
