Life cycle assessment (LCA) for ChemCycling®
Mechanical recycling remains the preferred recycling solution if proven to be ecologically most beneficial, technologically possible, and economically feasible. However, there are also plastic waste streams that are not suitable for mechanical recycling. An example are mixed plastic waste fractions, consisting of various plastic types, which will not be sorted further for mechanical recycling due to technological and economic reasons. This means that the most likely end-of-life option is incineration1, and the resulting energy is used to generate steam or electricity. In this case, chemical recycling is the better option. Chemical recycling complements mechanical recycling and can be a more sustainable solution than incineration or landfill of plastic waste. It thus contributes to a circular economy and the responsible use of resources.
1 In EU 27 currently almost the half of the plastic waste which is collected for mechanical recycling goes to incineration or landfill. In EU 27 landfill will be banned by 2035.
Meta study on LCA of chemical recycling (2023)
Life-Cycle Assessment studies on chemical recycling analyze the environmental footprint of the technology and products. Based on sound methodology, they provide transparency about the sustainability impact. However, one study cannot show the whole picture. Different approaches set varying system boundaries, take varying assumptions and highlight different aspects. We wanted to get an overview of LCAs on chemical recycling worldwide. Therefore, BASF asked Sphera to review the literature on LCA studies on chemical recycling (focus pyrolysis) and compare both their methodology and the results.
The global review included 15 studies published between 2003 and 2023 by academia, industry or NGOs which focus on pyrolysis of mixed plastic waste. The LCAs under review differentiated between two perspectives: Waste perspective and recycled product perspective. The evaluation of the LCAs focused on the carbon footprint of the technology.
The results of the review are summarized in the meta study. With regards to the carbon footprint, the meta study found that chemical recycling in most cases leads to a reduction. In the majority of the studies (7 out of 9) that address the waste perspective, pyrolysis shows better Global Warming Potential (GWP) performance than incineration with energy recovery. Only in very exceptional cases, where the energy grid is mainly based on fossil resources, energy recovery could currently be the better option. Pyrolysis shows better GWP performance than virgin production in all studies that address the product perspective.
The study identified a range of variables which determine the carbon footprint of chemical recycling: The performance of pyrolysis depends on the greenness of the energy grid mix used, the avoided waste management (incineration/landfill), pyrolysis yield, and end-of-life scenarios. Consequently, the shift towards a cleaner energy grid mix in the future and improvement in yield would further support the environmental performance of chemical recycling.
You can download the slide deck about the meta study in the downloads section of this page.
BASF’s LCA study (2020)
An LCA study conducted by Sphera for BASF, which was reviewed by three independent experts, comes to the clear conclusion that chemical recycling (pyrolysis) of mixed plastic waste emits 50% less CO2 than incineration of mixed plastic waste.
The study also compares the CO2 emissions of plastics produced with pyrolysis oil under a mass balance approach with conventional plastics made from fossil naphtha. It arrives at the conclusion that chemically recycled plastics cause significantly lower CO2 emissions than those produced from primary fossil resources. The lower emissions result from avoiding the incineration of mixed plastic waste.
Moreover, the LCA study found that manufacturing of plastics via either chemical recycling (pyrolysis) or mechanical recycling of mixed plastic waste results in similar CO2 emissions. It was taken into account that the quality of chemically recycled products is similar to that of virgin material and that usually less input material can to be sorted out than in mechanical recycling.
More detailed information on the results can be found in the download area. The complete study can be requested by persons with legitimate interest at email@example.com.
The results of this LCA study are comparable to those of a study from CE Delft commissioned by the Dutch government.
Life-cycle assessment of end-of-life tire pyrolysis (Pyrum 2022)
The sustainability of the recycling process for scrap tires used by our partner Pyrum Innovations AG is demonstrated by a life-cycle assessment conducted by the Fraunhofer Institute for Environmental, Safety and Energy Technology, which determined the CO2 emission savings of Pyrum's pyrolysis process. Pyrum's pyrolysis process is the first chemical recycling process to save more CO2 emissions than mechanical recycling of scrap tires. Compared to the current recycling mix in Germany, it even saves up to 72% more CO2 emissions. The life-cycle assessment scientifically proves that Pyrum not only closes the recyclable material loop, but also saves more CO2 emissions than all currently used, common recycling processes for end-of-life tires (current recycling mix for scrap tires in Germany: mechanical recycling (market share 52%), burning of scrap tires in cement plants (42%) and refuse derived fuel (RDF) power plants (6%)).
The study is published in "Resources, Conservation and Recycling", Volume 199, December 2023, 107255 and can be accessed here.