I take up this topic not only because it’s one of the top drivers of traffic to this blog, but also because I recently came across another life cycle assessment (LCA) of cups. It differs in important ways from the one I looked at and extrapolated from here (and which has driven so much traffic to this site).
This one was published in 2006 and looked at various types of cups, reusable and disposable, as used at large and small events. (There’s an overview of the study and a link to it here.)
The study found that, across the full life cycle, reusable cups had some environmental advantages over disposable cups but not in every environmental impact category. Aggregating environmental impact into a single indicator using subjective criteria, you could say (as did the report), that the reusable cups were environmentally superior. But, in contrast to my analysis, they cost much more.
The major components of cost difference are the cost to purchase the cups themselves and some factor called “lower drink consumption” whose meaning I can not discern from the report. This study assumes a much lower “trip rate” or number of reuses per cup than I did, which affects the economics significantly. But the scenario I looked at was a sit-down dining establishment where cups never leave the premises once delivered. So I speculate that a higher trip rate prevails in that situation.
The contrast between these studies reveals something about how sensitive LCA is to assumptions and system boundaries. But it’s a great tool for making sound, science-based environmental decisions.
We recently published a market study on LCA and the best practices for its use at corporations. See the report overview (and purchase a copy) here.
For those who want to follow along, I came upon the study mentioned here in a discussion on the “Life cycle thinking forum” mailing-list maintained by the European Commission Joint Research Centre for Life Cycle Thinking and Assessment.