vendredi 25 mars 2011

Polystyrene Foam Cups and Plates Use Less Energy, Water Than Paper or Corn-Based Alternatives

A new peer reviewed study finds that commonly used cups, plates and sandwich containers made of polystyrene foam use significantly less energy and water than comparable paper-based or corn-based (polylactic: PLA) alternatives, primarily due to polystyrene foam's much lower weight.
The polystyrene foam products create less, similar or more solid waste by volume than alternatives depending on the product and its weight, according to the study, and greenhouse gas emission comparisons vary widely, based on uncertainties over whether paper-based products degrade after disposal.
Some key findings:
  • Energy use: Polystyrene foam products consume significantly less energy than the alternatives – half as much as wax-coated paperboard cups and one-third as much as PLA clamshells.
  • Water use: Polystyrene foam products use significantly less water than the alternatives – up to four times less than PLA clamshells.
  • Solid waste: Polystyrene foam products create significantly less solid waste by weight than the alternatives – up to five times less than paperboard and PLA products. Comparisons by volume vary widely:
  • Polystyrene foam cups for hot drinks create less waste by volume than the alternatives – significantly less than paperboard cups with corrugated sleeves used for insulation.
  • Polystyrene foam cups for cold drinks create similar waste by volume as plastic coated paperboard cups and significantly less than wax coated paperboard and PLA cups.
  • Heavy duty polystyrene foam plates produce more solid waste by volume than the alternatives, while lighter duty polystyrene foam plates create similar waste by volume as the paperboard counterparts.
  • Polystyrene foam clamshells create slightly more waste by volume than paperboard clamshells and half the waste by volume of PLA clamshells.
  • Greenhouse gases: Polystyrene foam products generate slightly more greenhouse gas emissions than PLA products, expressed as net CO2 equivalents (see note below). If paperboard products do not degrade after disposal, they store carbon and generate fewer greenhouse gas emissions than polystyrene foam products; however, if paperboard products degrade to the maximum extent, they generate more greenhouse gas emissions than polystyrene foam products, so comparisons of greenhouse gas emissions vary widely depending on assumptions about the degradation of paperboard products.
Full study is available here
My comments:
  1. Are Styrofoam trays and cups sustainable packaging? The majority of LCA on Styrofoam trays showed a better footprint than paperboard trays?
  2. I’m very skeptical regarding LCA studies: data may not be accurate or complete and system boundaries are not easily defined
  3. LCA does not provide clear “winners or losers”. Furthermore, LCA will not determine which product or process is the most cost effective or works the best.
  4. LCA must be used as an internal process evaluation and improvement tool, and not a marketing tool

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