New study gives ‘green’ light to PET bottles over glass, aluminum

The LCI http://en.wikipedia.org/wiki/Life_cycle_assessment compared total energy, solid waste, and greenhouse gas emissions per 100,000 oz of soft drinks packaged in typical 20-oz PET bottles, 8-oz glass bottles, or 12-oz aluminum cans. The PET bottles showed appreciably lower numbers across the board, says PETRA.

Most notable were the lower greenhouse gas emissions for the PET bottles, which registered 59% less than aluminum and 77% less than glass. Franklin calculated the greenhouse gas emissions for the PET bottles at 1,125 lb of CO2 equivalents, compared to 2,766 lb for aluminum and 4,949 lb for glass.

Energy use for the PET bottles totaled 11.0 million BTU per 100,000 oz of soft drink, compared to 16.0 million BTU for aluminum and 26.6 million BTU for glass. Solid wastes for the PET bottles totaled 302 lb, versus 767 lb for aluminum, and 4,457 lb for glass.

Solid waste volume was 0.67 cubic yards for PET, 0.95 cubic yards for aluminum, 2.14 cubic yards for glass.

“This study again confirms the excellent environmental profile and value of PET for packaging foods and beverages,” says PETRA executive director Ralph Vasami. “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.”

Vasami says 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, the PET bottles still trumped aluminum or glass in terms of lower greenhouse gas emissions and solid wastes, while total energy use was deemed comparable for all three materials.

For both analyses, the LCI covered extraction of raw materials through container fabrication, as well as post-consumer disposal and recycling. The post-consumer disposal and recycling calculations included transporting to a landfill or incinerator, equipment operations at a landfill, and energy recovered by an incinerator, but excluded incinerator and landfill emissions. Post-fabrication transportation to the filling site, filling, distribution, storage, retail use, and consumer use were excluded.