The long road to PET circularity

Of all the plastic packaging currently subject to public scrutiny, polyethylene terephthalate, or PET, is one of the most visible, being the main component of single-use items such as plastic drinks bottles, and the subject of legislation and commitments to improve its sustainability.

Increasingly companies for whom PET plastic packaging is a cornerstone of their business are making pledges to switch to 100% recycled content in their PET plastic bottles – at least for their flagship brands. On the face of it, this is a noble aim. In a fully circular closed loop system, PET products would only be made from recycled PET (rPET) recovered from the same products – so bottles become bottles – removing the need for virgin PET and eliminating one route for PET to be lost from the system. A key environmental benefit of this is that by retaining recycled material in highly recyclable products, we can get dramatically more use out of a given amount of original virgin material. That means a much bigger reduction in demand for virgin material (with their associated carbon emissions and other ecosystem impacts) versus a second use that isn’t likely to be recycled at the end of its life – such as PET bottles being made into polyester textiles.

However, in a new report for Zero Waste Europe, called How Circular is PET?, we show that there are system limitations on recycled content in PET bottles that are likely to limit mechanically recycled content at around 75%, even in a very optimised scenario. And we show that the mountain we have to climb to get there is daunting – and we are barely in the foothills at the moment, even in Europe.

Currently most rPET goes into less circular applications and not back into the application it came from. For example, despite a recycling rate of 50% across Europe, new PET bottles contain on average just 17% rPET. In fact, PET bottles are the main source of rPET for all PET applications, including trays, textile fibres and disposable strapping, with 69% of 1.8 million tonnes of recycled flake output from PET bottles going to non-bottle applications due to high demand for recycled content and very low levels of recycling in non-bottle applications.

So, PET is currently not very circular, and there is much to be done to resolve that. Policy drivers are in place in the form of a minimum 30% recycled content requirement for plastic bottles in the EU’s Single Use Plastic Directive, with targets for bottle collection of 77% by 2025 and 90% by 2030. Dramatic improvements in collections of PET bottles will be needed, probably through the introduction of Deposit Return Systems, which can achieve high return rates of separated, high-quality PET. In turn, this controlled flow of material can enable closed loop bottle-to-bottle recycling and reduce the current cascade into less beneficial applications. The amount of coloured and opaque PET bottles on the market also needs to be reduced relative to the amount of clear and light-blue PET, as this is key to maximising the number of cycles that bottle material can continue to be used in bottles.

Making these changes won’t just make 30% recycled content a possibility, but taken to their fullest extent, our research shows that a recycled content in PET bottles of 75% is possible, with these changes also potentially increasing recycled content in all PET packaging applications to somewhere in the region of between 47% and 56%.

These upper limits are based on the assumption that closed loop recycling for PET bottles is prioritised to keep that high-quality material in this circular recycling system. To support this, policy-makers could consider higher recycled content targets and regulating to give priority access to rPET to beverage producers, to ensure they are not outcompeted for material by less circular applications.

Ideally though, society needs to finds ways of taking more system-wide approaches, to have the optimal impact across the board. For example, it seems clear that beverage bottles are a good use for rPET because they are so mechanically recyclable and so can probably make a bigger contribution to carbon emissions reduction through recycling-based circularity than any other application of rPET. So, does this mean that as we see the emergence of chemical recycling for PET, the output of these new processes should be focused on PET bottles, to get that virgin PET consumption down as low as possible? ?From an environmental point of view, the answer is probably yes – but the outdoor fashion and sports footwear sectors would probably beg to differ. Indeed, they may well be concerned about any regulation that gives priority access of conventional, mechanically recycled rPET to beverage producers.

And even amongst beverage producers there are some emerging issues. For example, as this report has shown, there will always be limits on availability of recycled content – and these limits are significant at the moment (leading to the sustained recent boom in rPET prices). Where companies have committed to using 100% recycled content in their bottles, they are committing to using the absolute highest quality material – given the quality requirements in bottles – which contributes to upward price pressure for that highest quality material and leaves less for other producers. But as we get to higher levels of recycled content in the overall pool (approaching that ‘optimised’ 75%), making a significant proportion of bottles from 100% recycled content may risk the quality of the rPET pool actually reducing – because as you concentrate the highest quality, most optically clear material in 100% recycled content bottles, the remainder of the pool is likely to decline in quality, necessitating the introduction of more virgin material into the system to maintain quality. There needs to be consideration given to the framework that is best suited to incentivising the distribution of rPET throughout the system so that market forces can be harnessed to drive us efficiently towards the lowest-emitting use of this material.

Changing the system rather than simply optimizing existing parts of it is no mean feat, and there is much to do to achieve an optimal, circular packaging system fit for the future. It is a long road ahead, but the tools are available to ensure we see circularity on the horizon.