The deposit scheme will increase the carbon footprint of a PET bottle from 4 to 11g of CO2

The carbon footprint of a PET bottle collected under the deposit system will be several times higher than the carbon footprint of the same bottle collected under the municipal system. Depending on the efficiency of the system and other factors, emissions will increase from 4 g CO₂/pc. up to 11 g CO₂/pc, and as much as 22 g CO₂/pc. On an annual basis, this will represent an increase in total carbon emissions of 96,000 tonnes.

BioVeradi expert report: deposit system triples the carbon footprint of a PET bottle

The introduction of a deposit system in Poland will result in a significant increase in the carbon footprint of the PET bottle - this is the conclusion of the Expert reports Carbon footprint developed by Beata Beata Waszczyłko-Miłkowska, Ph.D., and Jolanta Kamińska-Borak, Ph.D., of BioVeradi. In addition to the positive effect, e.g. the projected improvement in the efficiency of selective collection and recycling and the reduction of environmental litter, the deposit system will also have „side effects”, the scale of which can be seen by analysing the data from the report.

According to the authors' calculations, the emissions associated with the current municipal household waste collection system amount to approx. 4 g CO₂ per bottle. However, in the scenario of a fully functioning deposit system (100% collection), the carbon footprint of a single bottle reaches more than 11 g of CO₂. This result can only be achieved in the most optimistic of the analysed variants, in which not a single PET bottle with a deposit symbol ends up in the yellow bag. As the experience of countries where deposit systems have been in place for many years shows, it is virtually impossible to achieve 100% collection rates, especially in the initial period of operation. For this reason, in Expertise estimates for a 50 and 77 per cent collection rate within the system were also included.

• The highest carbon footprint of a PET bottle occurs in the 50% variant of system efficiency bail and is 16 g CO₂. It is mainly due to the parallel operation of 2 systems: the municipal and the deposit systems, which leads to duplication of waste logistics processes.
• With the statutorily required level of separate collection of PET bottles under the deposit system, the calculated carbon footprint of a single pack is 12 g of CO₂ and is 3 times higher than the current carbon footprint recorded in the municipal system.

As the report's authors report, the biggest contributor to the increase in emissions in the deposit system are the processes involved in collecting PET bottles (reverse logistics, use of bottle dispensers). The contribution of consumer transport alone to CO₂ of the bail system averages around 45%!

Communal collection generates less CO₂ than the deposit system.

The BioVeradi report is the first study of its kind to examines in detail the post-consumer phase (i.e. collection, transport and sorting of waste) and takes into account all the most common types of PET bottles marketed in Poland (from 0.33 l to 2 l).

The authors of the report not only present previously unknown data, but also call for their findings and calculations to be taken into account by regulators and legislators:

The result remains consistent: the municipal system gives a stable, low and acceptable level of emissions, while the introduction of a deposit system increases the carbon footprint and causes a negative environmental effect. This fact should be explicitly taken into account in the decision-making process on the shape of future waste management in Poland.

The expert report is based on a comprehensive calculation model that allows the impact of various factors, e.g. logistics, consumer and technology, on the total carbon footprint of a package to be assessed. 109 scenarios were analysed differing, among other things:

• efficiency of the deposit system (50, 77 and 100% collection of PET bottles up to 3 l),
• the share of individual car transport in delivering empty bottles to collection points (30, 50 and 75%),
• the share of bottle machines in the collection (50 and 75%),
• the level of allocation of returnable transport (PET bottles and beverage cans account for 30, 50 and 100% of the weight of freight carried, respectively),
• the number of logistical stages (2 and at least 3 stages).

In none of the scenarios presented did the bail system prove to be more advantageous than the municipal system emissions in terms of CO₂ - Even with 100% effectiveness of the deposit system, the lowest emissions would be 172 g CO₂/kilo PET bottles, while with 100% effectiveness of the municipal system they would reach 144 g CO₂/kilo PET bottles. It is worth noting that this most optimistic deposit scenario assumes the complete abandonment of the use of the car to deliver bottles to collection points, which is unrealistic in the current situation, especially in sparsely urbanised areas.

Other conclusions from Expert reports Carbon footprint

• Each year in Poland uses an average of 13.5 billion PET bottles. Changing the collection method from a municipal system to a deposit system may increase the total CO₂ from around 55,000 tonnes to around 150,000 tonnes per year.
• Regardless of the scenario analysed, emissions in the municipal system remain relatively constant. In contrast, bail system emission levels are largely determined by consumer behaviour.
• Even not using transport will not equate the carbon footprint of a PET bottle in the deposit system (5 to 9 g CO₂) with the footprint in the 100% municipal system (4 g CO₂).
• Due to the reliance of personal transport and waste logistics on vehicles with fossil fuel engines, possibility reduction in the carbon footprint of PET bottles collected through the deposit system is significantly reduced.

Source:

1. Dr.-Ing. B. Waszczyłko-Miłkowska, Dr.-Ing. J. Kamińska-Borak, Expertise Carbon Footprint, https://bioveradi.pl/wp-content/uploads/2025/10/BioVeradi-sp.z-o.o.-Slad-weglowy-pdf.pdf