Are plastics sustainable?

I know beforehand that with this story a lot of eyebrows will be raised and some sharp comments will follow. Plastics have the image to be environmentally unfriendly consuming the fossil resources which aren’t endless, polluting the world during their process as well as after their discard by the consumer. In short: In comparison with other materials, plastics suffer from a rather bad image with regards to environmental aspects and the consumption of resources.
And here is a study that claims that without plastics, substantially more energy would be consumed and more greenhouse gases would also be emitted.

The study “The impact of plastics on life cycle energy consumption and greenhouse gas emissions in Europe”, is conducted by Denkstatt-GmbH and commissioned (of course) by PlasticsEurope e.V., the European association of plastics manufacturers.
The results demonstrate that both energy consumption and greenhouse gas (GHG) emissions would increase significantly, if plastic products were to be substituted to a theoretical maximum by other materials. In other words plastic products, having substituted more traditional materials are helping save energy and reducing greenhouse gas (GHG) emissions.

The energy savings that can be attributed to the use of plastics varies significantly according to the application area, with packaging being by far the most important. A conservative estimate of the impact of the total plastics market has been made by extrapolation using only half of the energy savings and GHG emission reductions of the quoted examples.

With regards to the examples of plastic products which were examined in more detail, they concern exclusively plastics which are produced from fossil energy sources even if the role of renewable resources is becoming more and more important in the plastics industry. According to PlasticsEurope, the goal of the study was first and foremost to document that the use of fossil plastics also makes a positive contribution to the goals of energy efficiency and climate protection.

The results show that the total life-cycle energy needed to produce, use and recover plastic products in Europe (EU27+2) is 4.300 million GJ/a and the total life-cycle GHG emissions are 200 Mt/a. Furthermore it can be concluded that substitution of plastic products by other materials wherever possible would need around 57% (1.500 – 3.300 million GJ/a) more energy than currently used in the total lifecycle of all plastic products today. In the same way, substitution of plastic products up to the theoretical maximum would cause 78 – 170 Mt or about 61% more GHG emissions than the total life-cycle of all plastic products today.

In other words, the plastic products on the market today have enabled energy savings of 2.400 million GJ per year, equivalent to 53 million tonnes of crude oil carried by 205 very large crude oil tankers.
The GHG emissions saved (124 Mt per year) are equivalent to the total CO2 emissions of Belgium in the year 2000 [UNFCCC, 2009] and are also equivalent to 39 % of the EU15 Kyoto target regarding the reduction of GHG emissions.

Effects of prevented food losses on energy and GHG emissions
It was to be expected that the study should include the results of the use of plastics in food packaging. And here we go.

A rough estimation of the possible magnitude of CO2 savings resulting from prevented food losses enabled by plastic packaging for fresh food shows that the CO2 benefit of 10–20% prevented food losses is 4-9 times higher than the CO2 emissions of packaging production. Such use effects therefore have significantly more influence concerning GHG emissions than the packaging production (for those packaging applications where food losses occur and are avoidable).

If we assume that 70% of all food packaging (plastics and other materials) prevent the loss of 20% of the food packed (compared to distribution of goods without packaging), and if we assume the same CO2-ratio for packaging production and food production as in the examples given above, then the respective CO2 benefit for plastic food packaging can be estimated at 190 Mt of CO2 emissions.
In addition, 22 Mt of CO2 emissions are avoided, if plastic packaging used to pack fresh food as listed above prevents 10% more food losses compared to the theoretical situation that this fresh food would be packed in alternative packaging materials.

Polymers based on renewable resources are not per se better than conventional plastics based on fossil resources. The range of their GHG balance (due to feedstock selection and waste options) is much greater than the difference with conventional polymers. Plastics from renewable resources could contribute to reduction of GHG emissions in the future, if the renewable sources as well as the waste management applied are chosen advantageous.

Finally it has to be underlined that a fully comprehensive comparison of products should not only be based on differences in energy consumption and GHG emissions, but should involve a full “sustainability assessment” that covers all relevant environmental, economic and social effects of the investigated products.
So far the study.

Do I have to give a comment. No, this has been done by (among others) Adisa Azapagic, Professor of Sustainable Chemical Engineering in the School of Chemical Engineering and Analytical Science at the University of Manchester. She writes:
This study has only considered two sustainability aspects: energy consumption and GHG emissions associated with plastic materials and their possible substitutes. As acknowledged in the report, comparison of products and materials should not only be based on these two criteria, but should involve a much more comprehensive sustainability assessment, covering all relevant environmental, economic and social effects of the investigated materials and products.

Furthermore, the conclusions of the study are based on the assumption that plastic is replaced by alternative materials without any changes in the design, function or service of the products studied. Again, as acknowledged in the study report, this is a limitation of the study as changes in the design and function can often have a bigger impact on the total energy demand and GHG emissions than different materials. This should be borne in mind when interpreting and discussing the results of this study.

No need for me to add any comment.

You can download the study (pdf-file) by clicking the image at the right or this link: ”The impact of plastics on life-cycle energy consumption and GHG emissions in Europe” – denkstatt GmbH – June 2010

2 responses to “Are plastics sustainable?

    • Claude, in general, plastics (without additive and made from fossil resources) can’t be broken down by bacteria.
      The question is not, is plastic renewable or biodegradable. That’s of no importance and even dangerous, as most renewable plastics are occupying huge areas of arable land, rising the food prices consequently. And additives to make plastics biodegradable have negative consequences.
      The real question is, is plastic recyclable and do we recycle it. In other words, have we implemented systems to selectively collect post-consumer plastic and are we moving that lot to a recycling place or dumping it on a landfill.
      Plastic can be sustainable, but that has nothing to do with renewable. I object strongly renewable plastics for obvious reasons, not only in relation to food shortages, but also as the cgc’s are using it to greenwash their image, by telling you that it is biodegradable, which is (sorry for the word) bullshit. Nothing biodegrades in a landfill and there is already too much waste along the roads, just thrown away, because it is biodegradable. And btw most of the so-called biodegradable plastics frustrate the recycling stream, as do the additives.
      We have to learn that recycling, preferably cradle-to-cradle, bottle-to-bottle, is the only answer for the mess we (yes you and I) are making. The only way to find real sustainability is in recycling.

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