The paper Life Cycle Assessment of Beverage Packaging and the article Ranked: the environmental impact of five different soft drink containers compare five packaging types for carbonated beverages:
I initially thought glass was the most environmentally-friendly of the packaging types, but in fact, both versions, new and recycled, have the worst environmental impacts according to the study mentioned above (the study evaluates a number of impact categories including climate change, human toxicity, ozone layer depletion and more):
A 33cl empty glass beer bottle weighs in at 210 grams where the equivalent 33cl aluminum weighs 17 grams, or 12 times less.
The sheer weight of glass means that it requires a lot of resources (silica sand and dolomite) and energy (to melt materials), but the real issue is transport. Because glass weighs on the order of 10x more than aluminum and plastic, carbon emissions from transporting glass bottles are much higher than transporting cans or plastic bottles.
Recycled glass is better than virgin glass, but again, because of its weight and composition, it requires 90% more energy to recycle than aluminum does, and glass is just complicated to recycle.
Plastic has several advantages: it is lightweight and generates two times less CO2 as aluminum during production. And it requires less energy to recycle due to lower temperatures involved in melting the raw material.
BUT it has harmful environmental effects and does not recycle infinitely like glass and aluminum. Recycled plastic can be used 1–2 times for bottles before being downcycled to a lower quality plastic (example plastic bags).
Also, the recycled content of plastic bottles today is a mere 3–10%, whereas aluminum cans are composed of 73% recycled content. Coca Cola is moving towards selling 100% recycled plastic bottles, but again, this does not negate the fact that recycled plastic will end quickly in a landfill after a couple cycles, whereas recycled aluminum and glass can be used indefinitely.
Moreover, recycling rates for plastic are just much lower than rates for aluminum and glass and thus 80% of plastic has accumulated in landfills, dumps or the natural environment.
Manufacturing new aluminum is hugely energy-intensive, much more so than manufacturing new plastic or glass.
Why? Aluminum is trapped in bauxite ore. It requires 5 tons of bauxite to get 1 ton of aluminum and the chemical process for extracting the aluminum is not only very energy-intensive, but it leaves behind a toxic red sludge which releases Perfluorocarbons, a potent greenhouse gas. See the video below for a great explanation about manufacturing aluminum and the aluminum versus plastic debate.
However, because aluminum is extremely lightweight and easy to transport, and especially because aluminum recycles indefinitely and recycled aluminum takes 95% less energy to produce than new aluminum, recycled aluminum comes in as a clear winner for the best packaging type for carbonated drinks in terms of environmental impact.
Photo from a recycling facility in Cambridge, MA circa 2011. Aluminum cans remain the most recycled and recyclable beverage container on the market today.Recycled aluminum comes out as a clean winner among the package types for beverages — a fact that manufacturers are clearly aware of as beer makers are moving from bottles to cans and drink makers like Coca Cola and Danone are also announcing selling water in recycled aluminum cans instead of plastic bottles.
Wait, what — canned water?! This is ridiculous. As the video above concludes, we need to avoid falling into Jevons Paradox which states that when technological progress increases the efficiency with which a resource is used, the rate of consumption rises due to increasing demand.
All packaging, new or recycled, requires a lot of energy to make. So above all, we must cut down on using containers that we throw away or recycle after using, no matter the material and use refillable bottles instead.
Our local beer maker BAPBAP introduced a 1.89L reusable “growler” (a jug-like container used to transport draft beer) that you can fill with any of their beers for a deposit.
The growler from our local Parisian beer maker, BAPBAP.Gallia, another Paris-based beer maker, is working towards recuperating glass bottles to reuse directly (which is much better than going through the recycling process) but after some experimentation, they put this effort on pause after running into logistical roadblocks (mainly having to do with the labels!). But they insist it’s just a “pause” and that they’re actively researching ways to make this recovery program happen and other ideas to reduce their environmental impact.
Material choices largely determine the sustainability of our packaging products. This case study investigates whether glass packaging is more environmentally friendly than plastic packaging. It also explains how to assess and compare their sustainability!
For this, we will analyze two common retail products: a bottle of apple juice, and a jar of strawberry jam. What will the environmental impact be? And what happens when you take a full life cycle perspective? These questions are answered below.
In this case, we calculated the difference in impact between a plastic and a glass bottle packaging for apple juice. This analysis focused on the global warming potential of the product. So, how do the bottles compare?
The apple juice bottling materials are:
The impact of the molding process, which shapes the raw material into its bottle form, is factored into the material impacts. We excluded the bottle caps from the analysis, assuming they would be the same for the three options.
For the end-of-life scenario (waste processing), we assumed the incineration of the plastic bottles and the recycling of the glass bottles.
Winner: White glass bottle!
Figure 1: Per kg material, glass has a lower global warming potential than plastic packaging. (Values are not shown in all images due to confidentiality).
Figure 1 shows the global warming impact of the material and bottle production (blue) vs. the impact of the waste processing (green). It looks like the environmental impact of the glass is lower! So should we prefer glass bottles next time in the supermarket?
Well… no!
While the global warming impact per kg of material is lower for the glass packaging, the weight of the glass makes a big difference.
Glass bottles are much thicker and heavier than plastic bottles. Generally, the weight of glass packaging is multiple times heavier than plastic packaging! In our example, the 1 L glass bottle [1] is 17-18 times heavier than the plastic bottle [2].
When we ask ourselves whether to buy a glass or a plastic bottle, we should think about the impacts per bottle and not the impacts per kg material!
Figure 2 shows what happens when you increase the weight of the glass packaging material by a factor of 18.
Figure 2: Global warming impacts of the bottles.
Winner: Plastic bottle!
Because we need 17-18 times more material (in kg) for the glass bottle, its environmental impacts per bottle far exceed those of a plastic bottle!
Although waste processing has a lower environmental impact for glass bottles, the high material impacts cause a higher global warming potential for glass bottles compared to plastic bottles throughout their entire life cycle.
The heavier weight of the glass bottle means that in each transportation step along the supply chain, transporting the glass bottle costs more fuel. This makes shipping more expensive [3] and causes higher climate impacts.
While the depicted comparison is for CO₂ impacts, the environmental cost indicator (which contains more than just CO₂ impact), shows an even bigger difference: Here, the recycled PET bottle has almost 90% lower impacts than the glass bottle.
In summary, to be climate-friendly we should choose plastic bottles over glass, even if we don’t put them into the recycling bin!
Before we jump into the second case, let’s quickly explain how we measure environmental impact.
Environmental impact is measured in a variety of impact categories. A commonly used one is Global Warming Potential, which is expressed in kg-CO₂-equivalent.
However, Global Warming Potential does not account for plastic waste or the toxicity impacts of the bottles. For the next analysis, we will follow the Environmental Cost Indicator (ECI), a Dutch environmental indicator that combines all environmental indicators into one monetary value (Figure 3). This monetary value accounts for CO₂, toxicity, and many other environmental impacts.
The analysis is based on a Life Cycle Assessment, the standard calculation method for environmental impacts across the life cycle of a product or service.
Figure 3: Scheme of ECI calculation method
One of the core issues of measuring the environmental impact of packaging materials is that they are rarely a standalone product. If we took the environmental impact of the product itself into account, the packaging would drive a relatively small amount of the total impact. However, for this analysis, we compared only the packaging itself.
Here, we looked at three different packagings for strawberry jam:
The glass jar is 7 times heavier than the plastic jar.
For the waste scenario for the plastic bottles, we assumed 50% incineration and 50% recycling. For glass, we assumed that 85% of the glass is recycled at the end of its life, and the remainder is sent to the landfill.
To make it more realistic, we also added the same lid, made from polypropylene, to all jars.
An overall advantage of plastic over glass is that fewer products with plastic packaging fail at the supermarket. We took this into account in the following full-lifecycle calculation!
Taking a full life cycle perspective and considering ALL environmental impacts, plastic packaging still scores better than glass!
Figure 4: The three jars’ weighted score for all the environmental impacts (environmental cost indicator).
This analysis incorporates end-of-life scenarios – which means that the recycling or re-using of the materials was taken into account. The recycling rates are based on current Dutch waste statistics.
Plastic is overall more environmentally friendly in our examples. This was the case even when glass bottles were recycled and plastic bottles burned (assuming a less favorable waste processing for plastic in the bottle comparison).
Winner: Plastic packaging!
The analysis shows that the overall environmental impact of PET as a packaging material is lower. The main reason is that while plastic has a higher impact than glass per kg, we need much less kg of plastic to package our products.
Glass has an advantage in recyclability, however, because of the enormous difference in weight, the material and transport impacts of glass are significantly higher.
[1] Burch Bottle and Packaging. (n.d.). 1 LITER GLASS LONG NECK BOTTLE. Retrieved on 01.02.2024 from https://www.burchbottle.com/1Ltr-Flint-Long-Neck-28-400.
[2] Islam, M. S., Uddin, M. J., & Alshehri, K. (2018). Plastic waste and carbon footprint generation due to the consumption of bottled waters in Saudi Arabia. Res. Dev. Mater. Sci, 5, 1-3. Retrieved on 01.02.2024 from https://www.researchgate.net/figure/Average-and-median-weight-of-plastic-Bottles_tbl1_324151712.
[3] The Cary Company. (n.d.). Glass vs Plastic: 7 Factors to Consider for Packaging your Product. Retrieved on 01.02.2024 from https://www.thecarycompany.com/insights/articles/glass-vs-plastic-packaging