Part of the issue lies in Sweden's highly developed system of incinerating plants - keeping plastic in the waste stream ups the energy content of the stream. So while youth-oriented PUB department store recently introduced biodegradable shopping bags and major grocery stores ICA and Konsum will also do trials, a very vocal group of researchers at Chalmers has come out strongly against bio-bags and in favor of green polypropylene instead. Find out why below the fold.Chalmers Professor Thomas Hjertberg says biodegradable bags aren't the most sustainable and that the world should wait for green polypropylene bags, which will go into wide-scale production later this year at a Braskem plant in Brazil. Hjertberg says bio-bags take 3 to 6 months to break down in nature and composting wastes the energy that could be recouped from burning them.
Hjertberg also says life cycle analysis shows that whereas plastic produced from fossil fuels and biodegradable plastic have about the same amount of CO2 emissions over the bags' short lifetime, switching to a "renewable" source (sugar cane ethanol) to make green polypropylene bags cuts the CO2 load by around 70 percent. At least in Sweden, the green polypropylene bags could then be considered biofuel to be turned into heat energy at the incinerator.
While the argument may be sound, it is one of the cases where an LCA misses some cultural aspects of consumption. Replacing oil plastics with plant plastics or biodegradable plastics doesn't help us as consumers see the real effects of our everyday consumption. Ireland's PlasTax still seems like a better way to give the cost signal, and plastic-bag-free Modbury a better model. Come on Sweden! Via ::Aftonbladet (Swedish only)