Plastic is the most environmentally-friendly packaging material, concludes new US study

06 Dec 2018 --- A new US and Canadian study into the environmental effects of plastics has concluded that plastics are more sustainable than the material alternatives in terms of energy use, water consumption, solid waste, greenhouse gas emissions, ozone depletion, eutrophication and acidification. Published last month, the study conducted by the Plastics Division of the American Chemistry Council (ACC) found that replacing plastics with alternative materials such as paper and paperboard, glass, steel, aluminum, textiles, rubber and cork would result in significant net negative environmental impacts.

The 172 page report – entitled “Life Cycle Impacts of Plastic Packaging Compared to Substitutes in the United States and Canada: Theoretical Substitution Analysis” – analyzed six packaging types produced and sold in the US and Canada: carrier bags, caps and closures, beverage containers, stretch and shrink film, other rigid packaging and other flexible packaging. The study estimates that these packaging types account for 95 to 99 percent of plastic packaging use in the US.

The plastic resins investigated in the study were all sourced from fossil fuels (natural gas and petroleum). The researchers chose to exclude biomass-based plastic resin from the study because “the market shares of these materials are not yet sufficient to warrant analyzing their substitution with other materials.”

The analyzed material alternatives to plastics constituted steel, aluminum, glass, paper-based packaging including corrugated board, packaging paper, cardboard (both coated and uncoated), molded fiber, paper-based composites and laminates, fiber-based textiles and wood. Cork and rubber were included as alternatives in the caps and closures category.

The study found that “plastic packaging has lower impacts than substitute packaging for all impacts evaluated for both the US and Canadian scenarios for both decomposition scenarios.” Specifically:

• Plastics packaging requires less weight to perform the same packaging functions.
• Plastics have higher embodied energy compared to alternative materials, meaning higher energy credits for plastics disposed of via waste-to-energy combustion.
• Plastics require less water per kg compared to alternative materials.
• Plastics have no decomposition, meaning no associated methane releases when landfilled.
• Carbon sequestration credits for landfilled material is only assigned to biomass-based carbon content (e.g., in paper, paperboard, wood) and not to fossil fuel-derived carbon content in plastic packaging.

The report clarifies that, “Two scenarios were analyzed for substitute packaging. The ‘no decomposition’ scenario, which includes biogenic CO2 sequestration credit for all the biogenic carbon in landfilled packaging (i.e., no decomposition over time of any landfilled biomass-derived packaging), while the ‘maximum decomposition’ scenario is based on maximum decomposition of uncoated paper and paperboard packaging that is disposed in landfills.”

Plastics have no decomposition, meaning no associated methane releases when landfilled.

In defense of plastics
The scourge of global plastic pollution has become more prevalent in the mind of the consumer as a result of the “Blue Planet effect” and the work of numerous non-profit organizations raising awareness about the pitfalls of the material when left unrecycled. This has resulted in a number of notable movements, such as the introduction of plastic-free supermarket zones, for example in Amsterdam and London.

Regulatory bodies and big business have responded with support for a circular economy for plastics as defined by the Ellen MacArthur Foundation, while implementing bans and taxes on single-use plastic items such as straws and shopping bags. Meanwhile, packaging suppliers are launching paper-alternatives to plastics at an increasing rate. For example, Mondi has substituted plastic for paper in its FlexziBox pet-food bag.

However, there is a feeling in some industry quarters that anti-plastic sentiment is distracting from the net environmental benefits of plastics relative to alternative materials when properly recycled. Susan Selke, Director of the School of Packaging at Michigan State University, US, tells PackagingInsights that plastics have numerous benefits, including “recyclability qualities and the ability to maintain performance through a number of use cycles.”According to the report, plastics require less weight to perform the same packaging functions.

“We need to be able to deliver packaged water to those who do not have access to clean water from other sources. PET and HDPE are the obvious choices for this task. Non-plastic containers are very likely to have greater environmental impacts (from production, transportation, etc.) as well as being more costly.”

Steve Russell, Vice President of Plastics, ACC, believes that, “This report builds upon established data on the energy and GHG benefits of plastics, compared to alternatives [and] expands our understanding of critical environmental benefits beyond energy by highlighting key environmental indicators like water use and waste generation.”

“Plastics have many properties that make them a popular choice in packaging applications. Properties such as lightweight, durability, flexibility, cushioning and barrier properties make plastic packaging well suited for efficiently containing and protecting many types of products during shipment and delivery to customers without leaks, spoilage, or other damage. The results of this substitution analysis show that plastic packaging is also an efficient packaging choice in terms of a variety of environmental impacts,” the report concludes.

By Joshua Poole