The problems with plastic are widely known – but not well understood. The truth is, sometimes plastic is necessary. And when it comes to banknotes, polymer substrate is the green choice.
The idea of polymer being the greenest option may seem counterintuitive – but it’s backed by evidence rigorously tested in a wide range of independent life cycle analyses from central banks.
Analyses from central banks in England, Canada and Mexico show polymer banknotes have a lower environmental impact than their cotton-based counterparts. Why? Polymer banknotes are far more durable. They last 3–5 times longer in the cash cycle.
Because fewer banknotes need to be produced, raw materials use is reduced over time. Polymer banknotes significantly cut carbon emissions as well – especially those arising from transport during the distribution phase of the cash cycle.
The evidence for this comes from central banks. For example, a life cycle analysis from 2018 looked at the Banco de Mexico’s polymer series and found emissions had been reduced by 48.8% when compared with cotton-paper banknotes.¹
The Bank of England reached a similar conclusion. In 2017, a carbon footprint assessment of its polymer series found the carbon footprint of a £5 polymer note is 16% lower than a paper note, while the carbon footprint of a £10 polymer note is 8% lower.²
Both polymer series are printed on Guardian substrate – which achieves emissions reductions based on the strength of specialised film and polymer substrate. This is the result of decades of innovation in materials engineering.
Guardian banknotes are based on an ultra-strong film called Propanote™ Clarity C, which is produced exclusively for Guardian banknotes by CCL Secure’s sister company, Innovia Films.
The Clarity C film is manufactured inside a special four-storey chamber that uses gravity and air as part of a unique ‘bubble’ process. The film is inflated in tube-shaped bubbles, heated to softening point, and mechanically stretched to equal extents in both horizontal and vertical directions.
As the base layer, Clarity C helps give a Guardian banknote its trademark toughness, resistance to temperature, and smooth, impermeable surface– as well as a unique security signature that can be verified via machine inspection at speed. The film is then converted into a fully secure banknote substrate by the application of numerous layers of high-resolution print.
Polymer banknotes are not the same as single-use plastics. Consumers simply don’t throw banknotes away. Instead, at the end of their long life in circulation, polymer banknotes are returned to a central bank and securely sorted and shredded as a matter of course. This means they don’t get discarded and find their way into rubbish bins, streams or oceans. Rather, they are recycled and transformed into durable end-of-life products.
The process for recycling polymer banknotes is well established. Having already been sorted and shredded by central banks, polymer banknotes don’t need to be separated from other waste streams. Their smooth, impermeable surface also means they don’t need to be cleaned.
Sophisticated extruders can now process banknotes without any requirement to mix them with other polymer waste – which makes it easy to convert spent banknotes into polypropylene pellets. These are then on-sold as a commodity product.
Polymer banknotes gain a second life as durable products including building materials, automotive parts, park benches and more. In Chile, for example, Guardian banknotes are processed into a material with properties similar to natural wood, and used to make floors, roofs and furniture.
With this streamlined process in place, the rate of recycling continues to climb. In its recent report, ‘Cash: A Roadmap to Sustainability’, Reconnaissance International canvassed results from a 2021 survey of 43 central banks.
“[It] found that 92% of those disposing of their polymer banknote waste were either recycling their banknotes or moving towards recycling their banknotes. Two more had yet to generate enough waste to warrant destruction or recycling. In contrast 96% of those on paper banknotes and mixed/composite substrate sent their banknote waste to landfill or for incineration.”
The reality is that none of the alternatives to polymer banknotes can be recycled in significant volumes. The raw materials simply exit the value chain at end-of-life.
While the inherently superior strength of polymer substrate is somewhat self-evident, the sustainability benefits this durability brings are less intuitive. Environmental impacts must be assessed independently by central banks across the entire banknote lifecycle.
Thankfully, a wide range of lifecycle analyses have been published by central banks. They clearly show the superior strength and recycling potential of polymer banknotes delivers greater sustainability in the long run.
While it may seem counterintuitive, polymer banknotes are the green choice. It’s just one of the reasons more than 40 central banks have made the switch.