The Swedish Environmental Research Institute has published a paper comparing high-quality recycling with downcycling of plastics.
The research was conducted within the scope of a project that aims to give differentiated criteria for plastics recycling. Currently, Sweden’s Extended Producer Responsibility (EPR) regulation mandates that 90% of PET bottles and 50% of other plastic packaging should be recycled. However, these recycling requirements do not distinguish between high-quality, i.e. closed-loop, recycling, and downcycling.
“These recycling targets can be met through either recycling route, which favours the less costly process of grinding mixed waste plastics together and putting a low-quality product on the market,” the researchers explained. “Hence, the Swedish EPR creates an incentive for downcycling over the high-quality recycling of plastics…Because of the incentives for downcycling given by the current recycling targets, we see a need for assessing and highlighting the climate impacts and potential benefits of advanced sorting and high-quality recycling.”
The study compares three scenarios: no recycling, downcycling, and advanced sorting that allows for substantial high-quality recycling. It follows a basket-of-functions Life Cycle Assessment (LCA) approach that accounts for carbon footprint as well as broader system impacts, including primary material production, waste incineration, energy generation, and waste imports in Europe.
In the no recycling scenario, all packaging waste is modelled to be incinerated with energy recovery, since landfilling of combustible waste is prohibited in Sweden. In the downcycling scenario, the current Swedish 50% recycling target is met through the downcycling of mixed plastic packaging waste to railway sleepers, which substitute wood sleepers. In the recycling scenario, the 50% recycling target is met through the advanced sorting of the mixed plastic packaging waste into separate polymer fractions, corresponding to the performance of Sweden’s Site Zero. This sorting enables high-quality mechanical recycling of much of the material, while a smaller share is downcycled for plastic sleepers.
Results indicate that closed-loop recycling has the lowest climate impact, followed by downcycling, with incineration being the worst option.
Primary plastic production has the highest climate impact with regards to carbon footprint. Incineration of plastics in residual waste and post-use railway sleepers also contributes significantly to emissions. European landfill emissions are also a key contributor, particularly from methane emissions.
Results show that downcycling is better than incineration because it delays the incineration of plastics by using them in secondary products (e.g., railway sleepers). That ‘buys’ Sweden time to import and incinerate more plastic waste from other European countries. This reduces European landfill methane emissions in the short term, providing a temporary climate benefit.
High-quality recycling is shown to be the best option because it reduces demand for primary plastic production, which has a high carbon footprint; minimises total plastic incineration, avoiding direct emissions; and allows for increased imports of waste with lower fossil content into Swedish incinerators, displacing more harmful waste disposal practices abroad.
The researchers concluded that a Swedish policy instrument that only stipulates a recycling rate does not adequately address these climate benefits of recycling.
“The climate would benefit from a policy that also accounts for the quality of the recycled plastics,” they said.