Packaging from plastic, aluminum or glass – which is better?

First, let’s dispel doubts and misconceptions – when it comes to disposable packaging, none of the title materials is fully sustainable. Let us stress it again, to be sure: neither is completely environmentally friendly. There is no doubt, however, that some are less harmful than others. It is not always possible to give up packaging, just as it is not always possible to give them a second life on your own. So let’s assume for a moment that regardless of the type of packaging (and whether we could reuse it at home), we will only use it once. If we have a choice of plastic, aluminum or glass – what to bet on? An unequivocal verdict is not easy, but we will try to present the greatest advantages and disadvantages of each type of packaging, from raw material sourcing to the end of its utility value.

Plastic packaging

Plastic is by far the most harmful material in the event of careless disposal. Unfortunately, a small percentage of it is recycled, and at the same time it is the most common – almost 40% of polymer plastics produced in Europe is plastic for packaging [1]. For example, greenhouse gas emissions related to the production of 1 kg of plastic, disposable trays are equivalent to 1.54 kg of CO2 [1]. It is worth noting that this estimate concerns mostly recycled PET. There is no need to beat around the bush – this result leaves a lot to be desired. Nevertheless, plastic is worth mentioning here for comparison with other materials – not in every category of this competition it fares worse than its alternatives.

plastic packaging

Raw material

Plastic, in its most popular version (PET), is a material made of synthetic polymers. Without going deeper into the chemical processes necessary for its production, it comes from crude oil. It is a mineral, and therefore a non-renewable resource – and is heavily exploited for purposes other than the production of plastic itself. Oil extraction and processing has a very high carbon footprint (and ecological footprint in general). As much as 45% of the total emissions of this material is associated with obtaining the raw material for the production of plastic packaging [1].

Production

The production of plastic packaging itself is the second most emissive stage of its life cycle. For the aforementioned disposable trays, it is responsible for 38% of the total emissions. Compared to other packaging materials, it is not too bad. PET melts at a relatively low temperature, is very plastic and relatively easy to manipulate – so it does not require large (compared to other materials) energy expenditure in production.

Transport

In the case of transport, plastic is also quite good. It is a very light material and can be produced locally. Plastic packaging transport is therefore less emissive than with heavier materials. Emissions at this stage account for about 3% of total plastic emissions [1] – if, of course, we do not ship plastic packaging thousands of kilometers from where it is produced.

Disposal/recycling

Disposal and (unprofitable) recycling are basically at the heart of the plastic problem. Although plastic packaging is increasingly recycled (or at least some of it), it is still a relatively small percentage. In Europe, about 30% of the plastic produced is recycled [2] (in the world it is less than 15% [3]). The other amount goes to landfills (and the rest is used, for example, for energy production). Plastic stored in this way takes about 400 years to decompose and is largely shredded into a very harmful microplastic. Moreover, it is still more cost-effective to produce new packaging than recovering those that are in circulation. Plastic recycling is simply difficult and energy-consuming (additionally, let’s be honest – not everyone pays attention to its proper disposal).

Aluminum packaging

Aluminum packaging (eg beverage cans) is gaining popularity recently due to the notoriety of plastic [3]. Like any type of packaging, it has its own advantages and disadvantages. It is easy to recycle, but the emissivity of production is much higher than in the case of plastic. Depending on the energy source needed to power the production of such material, the amount of greenhouse gases emitted is from two to even 4-5 times greater than in the production of plastic [3]. The carbon footprint of the entire life cycle of an aluminum can, however, depends on many factors, including recycled aluminum content or the energy source used during production. Only that the impact of this material on the environment is not limited to greenhouse gases.

aluminum packaging

Raw material

Production of the vast majority of aluminum cans requires the extraction of bauxite, i.e. sedimentary rock. This is a large, costly and damaging project for the surrounding ecosystems – it requires heavy machinery (powered by fossil fuels) and a hole to be drilled in the ground. In addition to noise pollution, it is associated with large-scale land degradation and local biodiversity loss. What exactly are the effects of extracting bauxite? It is not known. In some countries, for example in Malaysia, small (relatively, up to 250 hectares) mines may operate without prior environmental impact assessment [4]. The effects of mining this rock, however, are easily measurable in rivers which waters may be contaminated with heavy metals, arsenic and mercury in very harmful concentrations.

Production

The processing of bauxite into aluminum is also detrimental to local water resources. The extraction of metal from the ore by chemical reactions is associated with the formation of by-products, often corrosive, which can contaminate both groundwater and surface water. Moreover, the production of aluminum products requires a lot of energy (but usually non-renewable) and water.

Transport

The great advantage of aluminum packaging is its high resistance to damage and low weight. As a result, transport is relatively easy and requires less fuel than heavier plastics. However, it should be taken into account that their production requires bauxite, mined on a large scale in only a dozen countries – often distant from the place of packaging production. All these kilometers should be added to the estimates of emissions from aluminum transport.

Disposal/recycling

Like plastic, aluminum “disposed” without treatment (in a landfill) takes several hundred years to decompose. Unlike plastic, however, aluminum packaging is very easy to recycle. Each can of any color can be processed and used an unlimited number of times. At the same time, it is a much more profitable process than in the case of synthetic polymers. Perhaps that is why aluminum cans are waste with the highest recycling percentage – in 2017, as much as 74% of them were recovered in Europe [5]. Another good news is recycling aluminum uses 95% less energy than producing it directly from bauxite.

Glass packaging

Glass is often used as an alternative to plastic because it is easily recyclable and non-toxic to the environment. Unfortunately, its production also leaves much to be desired. Just like aluminum and plastic – it is made of non-renewable raw materials, and the packaging made of it requires large amounts of energy during production. It is estimated that the carbon footprint of a glass bottle is on average the highest among all types of beverage packaging [6].

glass bottles

Raw material

Glass is made of several raw materials, the most important of which are sand, limestone and silica. Unfortunately, all of them are obtained at a certain environmental cost, although slightly less than bauxite (in the case of aluminum) or oil (in the case of PET plastic). Extraction of sand and limestone, which is done on a massive scale for construction purposes, is particularly problematic. In the first case, river and ocean ecosystems are often violated, and in the second, land ecosystems are destroyed and surface waters are polluted.

Production

The production of glass packaging itself is very energy-intensive. All because the glass, in order to form the desired shape, must be melted at a temperature of approx. 1200 C. Heating the furnaces therefore requires very large amounts of energy, greater than in the case of plastic and aluminum.

Transport

Unfortunately, glass packaging is fragile and heavy. Their proper protection during transport involves the use of more cardboard (or other materials) than in the case of alternative materials. Therefore, a little less are transported at one time. Moreover, due to their weight, they consume more fuel during transport.

Disposal/recycling

Fortunately, their recycling is quite efficient (although a bit more problematic than with aluminum). Each glass bottle or jar can be recovered an unlimited number of times. While glass recycling requires more energy than aluminum recycling, it requires much less energy than producing glass from scratch. The estimates are quite optimistic, given that the amount of glass bottles and jars recycled in Europe is 74% [7]. A potential obstacle to recycling this material is that it must be sorted by color. It also requires quite specialized equipment, so it is not always possible to do it locally. If glass packaging ends up in a landfill, it can take up to a million years to decompose.

The least harmful packaging – the verdict?

There will be no unequivocal verdict arising from certainty and strong conviction. We have no good solutions, only a little less bad ones. And the least bad thing, most likely, will be aluminum packaging – provided that all (or at least the vast majority) of it is recycled. If we do not have them at hand – choose glass. In an ideal scenario, recycled plastic wouldn’t be bad either – but given the slim chance that it will be recycled again, we won’t recommend it.

Regardless of what disposable packaging you choose – it’s best if it is a last resort. However, remember not to demand perfection from yourself 100% of the time and not to reproach yourself for a moment of weakness. Each of us has a right to it.

Sources

  • [1] European Comission 2013: Recycled plastic reduces carbon footprint of
    packaging [in:] Science for Environment Policy [received 13.07.2020].
  • [2] European Parliment News, 2018: Plastic waste and recycling in the EU: facts and figures [received 13.07.2020].
  • [3] Onstad E., 2019: Plastic bottles vs. aluminum cans: who’ll win the global water fight? Reuters [received 14.07.2020].
  • [4] Head J., 2016: Bauxite in Malaysia: The environmental cost of mining. BBC News [dostęp 14.07.2020].
  • [5] Euractiv, 2019: Aluminium beverage can recycling in Europe hits record 74.5% in 2017 [received 14.07.2020].
  • [6] Gujba H., Azapagic A., 2011: Carbon Footprint of Beverage Packaging in the United Kingdom. Towards life cycle sustainability management, 10.
  • [7] Mohan A. M., 2019: EU glass packaging recycling rate is stable at 74%. Greener Package [received 14.07.2020].
  • Pongrácz E., 2007: The Environmental Impacts of Packaging.
  • Ourgoodbrands, What is more eco: aluminium vs glass vs paper or plastic? [received 14.07.2020].
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