A couple of recent stories on PlasticsNews.com sharply illustrate the hazards of making claims about the environmental superiority of materials.
First came a story about a study showing that PET single-serve bottles have less impact on the environment than aluminum cans or glass bottles. The story was generated by a study commissioned by the PET Resin Association.
The study, conducted by Franklin Associates of Prairie Village, Kan., compared total energy, solid waste and greenhouse gas emissions per 100,000 ounces of soft drinks packaged in 20-ounce PET bottles, 8-ounce glass bottles or 12-ounce aluminum cans. The PET bottles showed lower greenhouse gas emissions, generated less waste and used less energy for their entire life cycle, the study said. The analysis covered the entire life span of the packaging — from extraction of the raw materials through disposal and recycling.
PETRA's Ralph Vasami pointed out that since 2005, PET containers have been the subject of several independent life-cycle analyses, “and PET has consistently shown itself to be a sound environmental choice whether compared to glass, metal or other plastics.”
Aluminum container manufacturers might have felt a bit underappreciated by the comparison. Less than a week after the PET report was released, they had some strong criticism about the study.
The Aluminum Association said PETRA's analysis showed “a consistent and selective use of outdated data for competitive materials, an issue that calls into question comparisons based on the report.” The group said more-current data about aluminum would have shown a 15 percent improvement in energy efficiency and 30 percent fewer greenhouse gas emissions.
The Aluminum Association will release its own life-cycle study this month. Its study is being prepared by PE Americas of Boston to inform the Wal-Mart scorecard process.
Aluminum Association President Steve Larkin likened PETRA's study to a “PR stunt.” Larkin said: “Traditionally, [life-cycle analysis] studies have not been used to attack other products since that's not the intent of an LCA. We'd like to see the LCA study continue to be used as a tool for self-improvement, not for PR stunts.”
I disagree with Larkin's assertion about LCA studies — they absolutely have been used in the past to attack other products. The researchers and trade associations that create these studies know that they are used to promote one material over another.
Plastics companies are eager for any information that they can use to combat what they consider to be public anti-plastics sentiment. If you tell them that a specific resin is more sustainable than another, they pay close attention. Sustainability experts hesitate to make such comparisons, though, and life-cycle analyses that rank materials tend to mix both objective and subjective measures. LCA is a science that is subject to second-guessing.
So while processors need to be informed about the materials they use, they also need to use these reports carefully.
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