by Greg Stevens
Let’s start with the basics. What makes green plastics green?
According to the definition on the Green Plastics wiki:
What makes green plastics “green” is one or more of the following properties:
- they are biodegradable
- they are made from renewable ingredients
- they have environmentally friendly processing
Because different compounds can satisfy some or all of these criteria to different degrees, there are different “degrees of green” in green plastics. To evaluate how “green” a plastic material is, you need to ask three questions:
- how quickly can the plastic be re-integrated into the environment after it is no longer being used?
- how quickly are the ingredients that go into making the plastic created in the environment?
- how much pollution or waste is created during the process of actually making the plastic?
Most of the publicity surrounding green plastics centers on the first two points. ENSO Bottles uses an additive in their plastic so that it satisfies #1 but not #2. Braskem’s “green propylene” satisfies #2 but not #1. The most informative articles circulating around on bioplastics recently have been trying to educate the public about the differences between “renewability” and “degradability”…. that is, the difference between points #1 and #2.
While this distinction is important, it leaves out the less popular “third side” of “green” in “green plastics”: #3, the production process.
This “third side” was launched into the headlines recently by NatureWorks. According to the new press release,
The manufacture of NatureWorks’ Ingeo™ plastic… emits fewer greenhouse gasses (GHGs) than the comparable manufacture of every other common petrochemical-based plastic, according to a peer-reviewed article published in the August 2010 edition of Industrial Biotechnology. The article, “The eco-profile for current Ingeo™ polylactide production,” was peer reviewed and approved for publication in Industrial Biotechnology by an independent panel of experts. The article documents the energy and GHG inputs and outputs of Ingeo™ production, including planting, harvesting, fermenting plant sugars, and resin production.
This places NatureWorks’ Ingeo™ plastic squarely ahead of most of the competition in the “green credentials” arena, satisfying all three of the points above.
Could NatureWorks’ Ingeo be even greener? There are always ways to be better. Some company could find a way to make production even more environmentally friendly, or could produce a plastic with even better properties than Ingeo while retaining its bio-based content and biodegradability.
But for now, Ingeo sets a standard that demonstrates that we don’t necesarily need the “trade-offs” between different aspects of green. It is a standard that the rest of the bioplastics world should aspire to.