Using pyrolysis-based chemical recycling to meet plastic recycled-content targets could emit up nine times the greenhouse gases compared with traditional mechanical recycling, according to a new study from the environmental group Zero Waste Europe.
The Sept. 27 study looked specifically at 2030 recycled-content targets under consideration by the European Commission and how they would help meet climate targets under the Paris Agreement to limit global warming to an increase of 1.5° C.
Drawing on data from research done for the commission by the consulting firm Eunomia, ZWE said that greenhouse gas emissions from recycling plastics using pyrolysis are nine times higher than those from mechanical recycling, and it said that "mechanical recycling must be prioritized over pyrolysis wherever possible."
The environmental group launched the study in a Sept. 27 webinar, where it invited plastics industry groups to participate and comment.
The managing director of Chemical Recycling Europe, John Sewell, said the results did not surprise him, but he argued that his association's technologies will play a role in handling hard-to-process plastic waste that can't be handled by mechanical processes.
"Is anyone really surprised that mechanical recycling has a lower GHG than chemical? I'm certainly not," he said. "As an industry, we are totally supporting the hierarchy of waste — that is, if it can be mechanically recycled, then it should [be]. We support that as an industry."
But Sewell, the secretary-general of the Brussels-based group, said "there exists a hell of a lot of plastic waste out there that is not mechanically recycled today."
"We see that there's an opportunity for us to fit and work together," he said.
The ZWE study comes as the European Commission is revising its Packaging and Packaging Waste Directive. The study looked at the impact of recycled-content targets of 30 percent and 40 percent.
The environmental group wants any new EC directive to be more explicit about limits on chemical recycling.
"Without adequate regulations, efforts to strengthen mechanical recycling will be severely hampered," the study said.
ZWE said the EC should specifically prioritise mechanical recycling and consider the climate impact of different recycling technologies when it sets targets for recycled content, as well as focusing on design for recycling and other steps to boost mechanical recycling.
"The revision of the PPWD should serve as a lever to make the packaging sector more circular and be in line with European climate commitments," said Lauriane Veillard, ZWE's chemical recycling and plastic-to-fuel policy officer. "If we are serious about achieving [a] net-zero emission economy, mechanical recycling must be preferred over pyrolysis."
But Sewell said it could prove difficult to meet any new targets without chemical recycling.
He suggested it's not possible to "wave a magic wand" and have mechanical recycling solve problems processing complex mixtures of plastic waste.
As well, he said that chemical recycling technologies can produce cleaner streams of recycled plastics that could go take food packaging plastic waste and reuse it more easily back into new food-contact plastic.
"Would you not agree with me that you don't want to wave a magic wand and say that mechanical recycling can solve all these problems," Sewell said.
The study's author, Johannes Betz with the Oeko-Institut, an environmental research organisation in Freiburg, Germany, told the webinar audience that the study did not compare the climate impact of chemical recycling against virgin plastics production or incineration.
But he suggested it would compare favourably.
"Of course, there are some benefits of chemical recycling compared to new plastics," Betz said. "And there's also a benefit of chemical recycling vs. incineration.
"We should use chemical recycling up to a certain point, but this point has to be very, very, very small as chemical recycling has not as much benefit as mechanical recycling," Betz said.
Another panelist, Fanny Rateau, a program manager with the Environmental Coalition on Standards, noted that the study found the biggest overall GHG benefit from a reduction in overall single-use packaging, of 20 percent, combined with enhancements to mechanical recycling.
"What is most important for packaging is to eliminate unnecessary packaging and transition from single-use to reusable plastic packaging," she said. "What's important is to prioritise mechanical recycling."
Sewell said the chemical recycling group also favoured prioritising reducing and reusing, before recycling.
"I could speak on behalf of the association that I'm representing here that every one of them to a person would say, 'Yes, reduce, yes, reuse, and then get to recycling,'" Sewell said. "And as a citizen, I fully agree, too."