The cradle-to-grave study, conducted by Franklin Associates for PETRA, compared total energy, solid waste and greenhouse gas emissions per 100,000 ounces of soft drinks packaged in typical 20-oz PET bottles, 8-oz glass bottles, or 12-oz aluminum cans.
Emissions
PETRA, the industry trade group representing North America’s producers of PET resin, said the most notable aspect of the study were the lower greenhouse gas emissions for the PET bottles, which, it said, registered 59 per cent less than aluminum and 77 per cent less than glass.
“Franklin calculated the greenhouse gas emissions for the PET bottles at 1,125 pounds (510.29 kg) of carbon dioxide equivalents, compared to 2,766 lbs (1,254.64 kg) for aluminium and 4,949 lbs (2,244.83 kg) for glass,” stated the association.
The report also concluded, stated PETRA, that energy use for PET bottles totaled 11 million British Thermal Units (BTU) per 100,000 ounces of soft drink compared to 16 million BTU for aluminium and 26.6 million BTU for glass.
Waste
Solid wastes for the PET bottles totaled 302 lbs (136.98 kg) versus 767 lbs (347.91 kg) for aluminium, and 4,457 lbs (2,021.66 kg) for glass
Commenting on the study, PETRA executive director Ralph Vasami said that since 2005, PET containers have been the subject of several independent life-cycle analyses with the polymer consistently showing itself to be sound environmentally whether compared to glass, metal or other plastics.
He said that after PETRA received the preliminary LCI report on the soft drink containers, it asked Franklin to go back and recalculate its findings on the basis of 10,000 equally sized 12-oz. containers.
Under this scenario, said Vasami, the PET bottles still trumped aluminium or glass in terms of lower greenhouse gas emissions and solid wastes, while total energy use was deemed comparable for all three materials.
Data used
For both analyses, the life cycle inventory covered extraction of raw materials through container fabrication, as well as post-consumer disposal and recycling, said PETRA.
The post-consumer disposal and recycling calculations, it continued, included transporting to a landfill or incinerator, equipment operations at a landfill, and energy recovered by an incinerator, but excluded incinerator and landfill emissions.
Moreover, post-fabrication transportation to the filling site, filling, distribution, storage, retail use and consumer use were excluded, added the industry body.
A reaction to this study from FEVE - the European Container Glass Federation - will be published on FoodProductionDaily.com tomorrow.