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"Our research shows that some reusable alternatives will never break even, because cleaning them requires more energy and generates more greenhouse gas emissions than manufacturing single-use plastic items," Shelie Miller Say. (Credit: Getty Images)

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Many sustainability-conscious consumers may think that reusable products have less impact on the environment, but how environmentally friendly are they? A new study reveals some surprising and counterintuitive results.

These consumers are moving away from disposable plastic products and turning to reusable alternatives. In the kitchen, fashionable alternatives include bamboo straws and beeswax sandwich wrappers.

In order to compare the environmental impact of common kitchenware products (disposable plastic and reusable), the researchers divided consumer kitchenware products into four categories: straws, sandwich bags and wrapping paper, coffee cups and forks.

"Don't always think that reusability is the best option."

They calculated the reusable environmental "payback period", which is defined as the number of times a product must be reused before the environmental impact of each use equals a comparable disposable plastic product.

They found that because energy and water are consumed every time reusable items are washed, some reusable alternatives can never reach the break-even point.

For example, reusable bamboo straws and two reusable sandwich storage methods-beeswax wrap and silicone bag-did not reach the break-even point in any of the three environmental impact categories evaluated by the study: energy Use, global warming potential and water consumption.

"Reusable alternatives have quickly become popular solutions to replace single-use products and help fight ubiquitous single-use plastics," said Shelie Miller, an environmental engineer at the Center for Sustainable Systems at the University of Michigan. Environment and sustainability.

"But don't always think that reusability is the best option," said Miller, senior author of the study in the International Journal of Life Cycle Assessment. "Our research shows that some reusable alternatives will never break even, because cleaning them requires more energy and generates more greenhouse gas emissions than manufacturing single-use plastic items."

Researchers report that, in general, reusable products that must be manually cleaned have a greater impact on the environment than products that can be placed in the dishwasher.

For example, compared with disposable plastic sandwich bags, beeswax sandwich wrappers that must be cleaned manually and have a large surface area can never reach the break-even point.

“Not cleaning the coffee cup after each use may make some people feel uncomfortable, but for others, this is actually a very standard practice.”

On the positive side of the reusable ledger, 9 out of 12 reusable items can reach the break-even point, even if they are cleaned after each use. For all three environmental impact categories, all three reusable fork substitutes (bamboo, reusable plastic and metal) have a payback period of less than 12 times.

Hannah Fetner, lead author of the Center for Sustainable Systems, said: "A key conclusion of our research is that we now understand what factors contribute to the environmental impact of reusable and disposable kitchenware products. "Knowing which factors are the most influential can help consumers most effectively reduce their own influence."

For example, it has been found that the payback period of reusable kitchenware is highly sensitive to washing frequency and washing method. Porcelain cups have the lowest overall impact in the coffee cup category, and consumers can further reduce these effects by occasionally choosing to rinse them quickly with cold water rather than thoroughly, Miller said.

"Not cleaning the coffee cup after each use may make some people feel uncomfortable, but for others, it's actually a very standard practice," Miller said.

Other tips for consumers who want to reduce the overall environmental impact of kitchenware products include:

The authors say that although consumers’ decisions about kitchenware are important, it’s important to remember that kitchenware products account for only a small percentage of anyone’s environmental footprint.

They say that the potential environmental improvements associated with reusable products are usually small compared to emissions associated with household transportation, energy use, and food choices.

In their research, the researchers examined the environmental impact of kitchenware products throughout the life cycle from resource extraction, manufacturing, and transportation to product use and disposal. According to Miller and Feitner, reusable products usually use more resources and energy during the manufacturing stage, but over time these "upstream effects" will become less important.

Previous research looked at the payback period of consumer products including air conditioners, refrigerators, washing machines and automobiles. Miller said that a study frequently cited by the Dutch government found that reusable food bags usually need to be reused hundreds of times to make their impact on the environment less than that of disposable plastic food bags.

According to Miller and Feitner, these early studies and new current investigations emphasized the complexity of product sustainability, the nuances of the environmental impact of reusable items, and the multiple factors and behaviors that influence the results of the research. .

Original research DOI: 10.1007/s11367-021-01946-6

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