How much CO2 does deposit return save?

What is the link between deposit return schemes and CO2 emissions?

Everything we do costs energy, and this includes the production, consumption and processing of beverage packaging. The exact design of this system matters. The choice of materials for beverage packaging, the transport of the packaging to the shop, the way we collect the waste – all of this determines how large the CO2 footprint of the beverage packaging is.

Below, we calculate the difference in CO2 emissions between deposit return systems and the current collection systems in the Netherlands and Belgium.

The Netherlands

Plastic bottles

In 2017, CE Delft carried out a study commissioned by the Ministry of Infrastructure and Water Management into the costs and effects of deposit return schemes. The study also calculated the CO2 savings generated by deposit return schemes on small plastic bottles and cans.

The CO2 calculation in the deposit study relies heavily on a 2011 study by CE Delft mapping out the environmental differences for various collection systems. The conclusion was that the amount of recyclate produced and used in new products is decisive. The influence of transport, compared to the reuse of the material, is limited, for example.

The deposit study estimates that currently 58% of small plastic bottles are effectively recycled. If this is increased to 90% with a deposit return scheme, it would yield an annual CO2 saving of 20 ktonnes for plastic bottles.

Cans

For cans, a distinction is made between steel cans and aluminium cans. The study estimates that the differences for steel cans are limited because they are relatively easy to recover from incinerators. However, larger losses occur with aluminium cans. The study currently estimates a recycling rate of 62% for aluminium cans. With a 90% return rate for cans, the study concludes that 96% of aluminium cans are eventually recycled. This leads to a CO2 saving of 34 ktonnes.

The expansion of the deposit return scheme to plastic bottles and cans, assuming a 90% collection rate, would therefore yield an annual reduction of 54 ktonnes of CO2 emissions in the Netherlands.

We do make two caveats regarding these figures. First of all, currently fewer plastic bottles are recycled than the 58% rate used by CE Delft for comparison. A return rate of 90% thanks to a deposit return scheme would therefore be a greater improvement, and achieve even more CO2 reduction.

The current calculation method also includes moisture and adhering dirt in the collected weight of plastic bottles. This leads to an overestimation of current recycling, and thus an underestimation of the environmental benefits of a deposit return scheme. According to sorting analyses by Eureco commissioned by Rijkswaterstaat, it appears that 41.8% of the weight of plastic bottles actually consists of moisture and dirt. It is to be expected that plastic bottles counted as 'recycled' also contain a similar proportion of moisture and dirt, making the actual recycling rate of small plastic bottles substantially lower than 58%. It is more likely to be between 30 and 40%. The actual CO2 benefit of 90% collection via deposit return schemes will therefore be substantially higher than previously calculated.

Flanders

Plastic bottles

In 2015, the official Flemish Waste Agency OVAM conducted an impact analysis on the introduction of deposit return systems for one-way beverage packaging. This analysis did not calculate the CO2 savings of a deposit return scheme.

From the Dutch research work, it can be concluded that the use of recycled material is the most important factor for determining CO2 savings. According to the Dutch deposit study, the extra recycling of 7.6 ktonnes of PET leads to CO2 savings of 34 ktonnes. That means 4.47 ktonnes of CO2 savings per ktonne of extra PET recycling. For aluminium, the study assumes 7 ktonnes of CO2 savings for every kilotonne of extra recycling.

To apply the Dutch key figures to the Flemish situation, it is necessary to determine by how much the recycling share in Belgium would increase as a result of deposits on plastic bottles and cans, as also stated in the OVAM impact study. We make the calculation below.

According to research by Recover, half of the PET bottles on the Flemish market are recycled (according to figures from Fost Plus this is 87.7%, but their calculation method leads to overestimations). In Flanders, 32 ktonnes of PET is used annually for beverage packaging. If recycling improves from 50% to 90%, then an extra 12.8 ktonnes of plastic is recycled. Based on the Dutch CO2 savings of 4.47 ktonnes per ktonne of PET recycling, this amounts to 57.2 ktonnes of CO2 savings in the production of plastic bottles in Flanders.

Cans

In the Flemish deposit study by OVAM, it is stated that 4.966 ktonnes of aluminium cans are placed on the Flemish market annually, of which 69.2% is separately collected and recycled according to the study. This yields 3.436 ktonnes.

That leaves 1.530 ktonnes of aluminium. If we assume that this aluminium goes to the waste incinerator, some of it is recovered from the bottom ash. Its efficiency is estimated at 62% in the Dutch deposit study. Research by Recover cites research by HJ P Claassens, which calculated a recycling efficiency of aluminium from bottom ash of 32%. Based on an efficiency of 32 to 62%, a further 0.489 to 0.948 ktonnes is recovered.

With the current system in Flanders, a total of 3.925 to 4.385 ktonnes of aluminium from cans is therefore recycled.

A deposit return system with 90% separate collection would, together with the recovery of aluminium from incinerators (for the remaining 10% of cans), result in a total recycling rate of 93.2 to 96.2%. This would recycle 4.589 to 4.777 ktonnes of aluminium. Compared to the current situation, this represents 0.392 to 0.663 ktonnes of extra recycling. Assuming 7 ktonnes of CO2 savings per ktonne of extra aluminium recycling, there is a 2.7 to 4.6 ktonne CO2 reduction with deposits on cans.

The expansion of the deposit return scheme to plastic bottles and cans, assuming 90% collection, would therefore yield an annual reduction of 59.9 to 61.8 ktonnes of CO2 emissions in Flanders.

Deposits on plastic bottles would reduce CO2 emissions in Flanders (assuming 90% separate collection) by about 59.9 to 61.8 ktonnes of CO2. That is more than in the Netherlands (54 ktonnes of CO2). This has three main causes. First of all, the Netherlands already has a deposit system for large plastic bottles, so they are already well collected and recycled. Secondly, in Flanders, a relatively high volume of beverages is consumed in plastic. Thirdly, in the calculation for the Netherlands we assume an artificially high recycling rate for small plastic bottles, while in Flanders, Recover has made a realistic estimate of the recycling of plastic bottles.

Deposits on plastic bottles and cans help to reduce the CO2 footprint in the Netherlands and Flanders combined by about 115 ktonnes. Planting trees is a popular method to offset CO2. An average tree removes about 20 kg of CO2 from the atmosphere annually. This means that the CO2 environmental benefit of a deposit return system in Flanders and the Netherlands in one year is equivalent to the amount of CO2 that 5.8 million trees remove from the atmosphere in a year.

Effect on the climate impact of the soft drink and water industry

For a can of Coca-Cola or a bottle of Spa, the packaging is responsible for a significant part, and sometimes even the largest part, of the climate footprint.

At the Spadel Group, packaging and ingredients are together responsible for 55% of the total carbon footprint, according to their own report. Production (20%) and logistics (22%) carry less weight than the bottles themselves. More and more producers realise they need to become climate neutral. One of the best ways to achieve this is by using recycled materials.

By replacing virgin PET with recycled PET (rPET), the total CO2 footprint of the packaging can be greatly reduced. According to the Ecoinvent dataset (v3.4 for IPCC 2013 GWP 100a), the contribution of rPET is 0.472 CO2 eq/kg and that of virgin PET is 2.92 CO2 eq/kg. The production of new, virgin PET plastic causes more than five times as much CO2 footprint than using recycled PET. This means that a plastic bottle made of 100% recycled material has an 80% lower climate footprint than a bottle made of virgin PET (the exact savings may vary depending on local circumstances).

Deposits help producers in two ways. Firstly, they ensure that more material is collected for reuse. This allows the proportion of recycled material in a bottle to be increased. Secondly, deposits ensure a clean stream of recycled PET, which can be used directly for new bottles. The PET collected in the Netherlands with 'Plastic Heroes' and in Belgium with the blue bag contains more contaminants. This makes Plastic Heroes PET and blue bag PET harder to use in new PET bottles.