Reusable and Disposable Cups: An Energy-Based Evaluation

A group of five different types of reusable and disposable hot drink cups have been analyzed in detail with respect to their overall energy costs during fabrication and use. Electricity generating methods and efficiencies have been found to be key factors in the primary energy consumption for the washing of reusable cups and a less important factor in cup fabrication. In This is not an easy question to answer because of the widely differing nature of the materials used and the conditions required to make reusable and dispos- able cups, e.g., pottery clays, glass, plastics, and paper. The fundamental property common to each of these cup types is the total energy required to produce the cup or mug ready for use, which is a well-established criterion for the comparison of disparate materials (e.g., Boustead and Hancock 1979, Kindler and Ni- kles 1979, 1980, Ringwald 1982). Available back- ground information from previous studies of the merits of cup options are individually and collectively incomplete. The study carried out in the Netherlands did not consider polystyrene foam cups (van Eijk and others 1992), the Winnipeg Packaging Project did not examine ceramic (earthenware/stoneware) cups (Fen- ton 1992), and our own previous contribution did not review reusable cups (Hocking 1991 b). Furthermore, the frameworks used in these assessments were suffi- ciently different to make it difficult for direct compar- isons to be made between them. This paper examines the tabrication energy for five of the common hot drink cup types applying the same methodology to each and tabulates the energy required for various widely used commercial washing and sanitizing methods employed for the reusable types. The combined information is then integrated to determine the energy requirements per use for various service scenarios of each cup type and to de- termine the break-even energy requirements for each of the reusable-disposable cup pairs. Brief consider- ation is given to the effects of various disposal options. Finally, a few tests are applied to determine tile sensi- tivity of the energy requirements and break-even