Plastics recycling is not the holy grail

Chemical recycling of waste plastic has been the subject of two recent announcements. Dow is partnering with Fuenix to produce chemically recycled plastic in the Netherlands. Zerowaste Europe has said that chemical recycling can complement mechanical recycling. The Zerowaste Europe report is good news, signalling an acceptance of a role for chemical recycling, but it fails to address the ongoing need for virgin plastic. Unfortunately, plastic recycling will not get us to an El Dorado where we don’t need virgin plastic.

There seems to be a general belief that the demand for single use plastic, mainly packaging, will reduce over time and that this diminishing requirement can be met with a combination of mechanical and chemically recycled material. But that ignores the demand for durable plastic, which currently exceeds that for the single use grades. The demand for durable polymers for electric vehicles and wind turbines will grow as we transition to a low carbon economy.  Plastic is increasingly being used for pipes, furniture and in buildings. Also, more single use material may be needed as the world’s population rises and becomes richer. For instance, as cities expand, more packaging will be needed to protect food as it travels longer distances to feed more people. 

Plastic is not infinitely recyclable like metals. The processing required to turn pellets of used plastic into new products during mechanical recycling, degrades its properties leading to downcycling into lower grade applications. After a few cycles it is currently fit only for incineration or landfill. Chemical recycling, in which the waste plastic is broken down into smaller building blocks and then repolymerised to virgin quality plastic, is largely at the pilot plant stage. Results suggest that chemical recycling processes that take mixed waste are nowhere near 100% efficient. 

So virgin plastic will be needed for the foreseeable future to meet increased demand and the inefficiencies of recycling.  We should therefore be looking for lower environmental impact substitutes, such as bioplastics made from renewable resources. But the belief that recycling is the complete solution is diverting support away from these renewable plastics.

Plastics production has grown up with the fossil fuel industry and their destinies are intertwined. Much more renewable electricity will be used for road transport and heating so the role of the oil industry will diminish and the economics will change. Some companies have commercialised chemicals and polymers made from renewable resources, but they can’t yet compete on price. 

Polyethylene made from sugarcane is already on the market so it can be used for applications such as food contact, which is not suited to mechanical recyclate. This biopolyethylene can be recycled with conventional material. In the future, CO2 in the atmosphere could also provide the carbon for new plastic, with the energy required coming from renewable sources. These bioplastics have the advantage of a lower carbon footprint than virgin fossil plastic, so are compatible with a low carbon economy. 

Lets definitely continue to work on new recycling processes, but at the same time we should accept that a nirvana where virgin plastic is no longer needed is a fantasy that risks diverting us from the deployment of renewable substitutes.   

Published: 9 September 19

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