IVL Swedish Environmental Research Institute

This report was written within the project Differentiated recycling criteria for plastics for a more sustainable recycling of plastics in Sweden (Differentierade plaståtervinningskriterier för en mer hållbar svensk plaståtervinning). It is based on the observation that the Swedish Extended Producer Responsibility stipulates the share of plastic packaging waste that should be recycled but does not address the quality of the recycling. The existing recycling targets are most easily met by grinding mixed waste plastics together and putting a low-quality product on the market. This low-quality material can replace, for example, wood in construction products.

To replace primary polymers, waste plastics need to be sorted into separate polymer fractions before recycling. This entails additional costs. However, such high-quality recycling can reduce both primary-plastics production and incineration of plastic waste. The choice between downcycling and high-quality recycling also affects the waste treatment of subsequent products and has indirect effects on the broader waste-management and energy systems.The project aimed at contributing to the understanding of the climate aspects, in a broad systems perspective, of downcycling and high-quality recycling of packaging plastics from Swedish households. We did this by identifying a method for modelling recycling that accounts for important systems impacts, and by applying this method in a comparison between no recycling, downcycling, and advanced sorting that allows for substantial high-quality recycling. 

Our assessment model accounts for the impacts of downcycling and high-quality recycling on the production of primary materials, on Swedish waste incineration, on waste imports, and on the waste management and energy systems in the rest of Europe. The system investigated was expanded into a basket of functions: the function provided by 1 tonne of primary-plastics packaging, 5 railway sleepers, the treatment of 1.02 tonnes of near-term and 0.50 tonnes of future European waste, the production and use of 5.1 GJ of near-term and 1.3 GJ of future gas, and the supply of 238 kWh of electricity. The assessment was comprehensive but includes substantial uncertainties.Our results are rough estimates of actual systems effects. They indicate that downcycling is better for the climate than incineration of the packaging plastics, mainly because the incineration is postponed until after the end of the second use of the downcycled material. This allows for a greater near-term import of waste that, in turn, reduces landfill disposal of mixed waste in other countries.

The case with advanced sorting has the lowest climate impact, because it involves the least primary production of polymers and the least total incineration of waste plastics. A plastics-recycling policy should provide incentives for high-quality recycling as this facilitates the substitution of primary plastics and a reduced incineration of plastic waste. The basket-of-functions approach allows for assessing the complex system impacts of recycling. The results include no avoided burdens, but only the emissions associated with generating the many functions of the system. The approach can be used to quantify the system impact of changing a single flow.