Bioplastics: Fantastic or Fraudulent?
You remember how it happened. You went to some chic Whole-Foods copycat, paid an exorbitant sum for some panini oozing in foreign cheese, and were about to eat it when you read that curious oxymoron on the plastic container: "biodegradable plastic". Once the part of the novelty of upper-crust retailers, bioplastics are now part of the mainstream. All of the University of Washington's disposable utensils, for example, are made of corn-based bioplastics that can be conveniently composted in one of the many receptacles on campus. But given that the public (and the farm lobby) touts ethanol (another corn derivative) as environmentally friendly, even though it produces more CO2 than gasoline per unit energy, I was left wondering whether corn-based plastics are really better for the environment than their petroleum cousins.
Manufacturing and disposal are environmentally detrimental in an enormous number of ways, so it is often difficult to compare the effects of one material with the effects of its substitutes. Given the exigency of global warming, one starting point is to compare the carbon footprint of a kilo of corn-plastic with a kilo of real plastic. A little work on Google gives very wide range of answers, that seem to cluster around a 40% or so reduction in carbon. One study says 42%, for instance. It is not surprising at all that there should be a wide variance in the carbon footprints of bioplastics. Much of the energy used in the manufacturing is in the form of electricity, whose carbon footprint per kilowatt-hour ranges from nearly zero (e.g. wind, hydro, nuclear) to very large (e.g. coal). This suggests that producing a fork from scratch out of corn instead of petroleum probably produces a modest amount less CO2.
But there are complications. Realize that a lot of plastics are actually recycled, producing considerably less carbon. I had a difficult time determining a figure for the carbon savings from recycling versus new production, but some sources claim that recycling cuts the carbon footprint of a kilo of plastic by about 50%. This seems believable, though I wouldn't put too much stock in this figure. For disposable products like plastic cutlery, this puts recycled plastic on par with bioplastic. Depending on the energy source used in manufacturing, bioplastic is probably preferable due to the fact that it is more easily disposed of by commercial composting.
What about items like plastic bottles that can easily be recycled? Conventional bioplastics are not recyclable. Contamination of ordinary plastics with bioplastics ruins the recycling process, potentially causing net recycling rates to decline. This is particularly problematic because it is often difficult for consumers to distinguish between bioplastic and conventional plastic. On the other hand, recycling rates for items like plastic bottles are fairly dismal anyway, so the compostability of bioplastics may give it an edge in disposability.
From an economic perspective, bioplastics also present some problems. To the extent that manufacturers substitute bioplastics for recycled plastics, demand and prices for recycled plastic will decline. Recycling post-consumer plastic is already difficult/impossible to do profitably as detailed in a fascinating Economist report on waste. Even a relatively small substitution from recycled plastic to bioplastic could severely undermine the plastic recycling industry, forcing it out of business or to rely even more on public subsidies that would be more efficiently spent on other forms of carbon sequestration.
Finally, it is worth noting that bioplastics and regular plastics have two very different environmental consequences. One increases farming, which is quite bad for the environment. But the other increases petroleum production. It's unclear to me which is worse, but there is one remark worth making. Recycling plastic does not actually require any petroleum in theory--it only requires energy. So recycled plastics don't directly contribute to increasing petroleum production (at least up the recycling efficiency). Bioplastics, on the other hand, always require a farm to grow corn. From this standpoint, recycled plastic may have a lesser environmental impact as long as renewable energy is used in production, or as long as the amount of fossil fuels does not exceed to the amount used in bioplastic production.
While I am somewhat uncertain of the relative environmental impacts of both types of plastic, it seems that bioplastics are generally superior for items like disposable forks that would never be recycled anyway, while recycled plastic is best used in products that have high probability of being recycled again. Like ethanol, bioplastics unfortunately will probably be touted by the farm lobby as part of their wildly successful rent-seeking enterprise to fleece the American taxpayer and immiserate third-world farmers. One should consequently remain skeptical about their environmental benefits, but welcome them in strictly disposable applications.
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I read through the article and thought is was great that manufacturers are creating things which are green and eco friendly. It is a goood idea, and definitely encourages people to become more aware of the lifestyle choices they make. I am trying hard to become more eco friendly, I have started sending free egreetings rather than paper cards. Traditional cards are fine as long as people remember to recycle, but I really don't reckon they do. I also try and walk or if I have to use transport, take the bus. Any one else have any other ideas to help out?
I found this article very insightful and the author seems pretty well informed. I would just add that all of these biodegradable plastics are only biodegradable in commercial facilities. Therefore, the rates of proper disposal/collection would probably be no better than recycling. So the problems of proper disposal would remain.
Actually, the part of oil used to make plastic is a byproduct of fuel production, and most of this would go to waste if it weren't turned into plastic. This fraction of oil is called light naphtha, and it's too volatile for most other uses. You can also make conventional plastic biodegrade in landfills-see http://biogreenproducts.biz to learn more. The carbon issue aside, making food into plastic isn't a morally acceptable idea when a billion people are hungry every day--naturally, this idea originated with huge amoral corporation - Dow Chemical Co. - now carried forward by another, Cargill, Inc.