North Energy Associates

Work carried out by the Resources Research Unit at Sheffield Hallam University, under Professor Nigel Mortimer (who has also carried out work on biofuels – click on the PDF icon for example) ranks various kinds of commercial buildings on the basis of their energy use and CO₂ emissions per square metre. The study looks at both food and non-food related premises.

Supermarkets, per square metre, are far more energy intensive than other food shops. If however one were to measure energy use per volume of food turnover, the conclusion could be different since this tends to be higher in supermarkets than in small independent stores

Whatever the balance, it is clear that refrigeration accounts for a large proportion of supermarkets' intensive energy use, accounting for 42% of store carbon emissions (electricity and gas combined). This heavy use of refrigeration reflects both the type of foods that supermarkets sell and the decisions made as to whether or not they need to be displayed in a refrigerated unit. Meat is arguably one product that really does need to be stored cool and if the Sheffield Hallam data for butchers' shops and for supermarkets are compared, one finds that both use fairly similar amounts of refrigeration per square metre. However, when it comes to fruit and vegetables it is interesting to note that greengrocers use almost no refrigeration whereas in supermarkets, many fruits and vegetables are displayed in refrigerated cabinets.

Most supermarkets are now open from Monday to Saturday from 8am to 10pm, and are open for much of Sunday too. Some larger stores are even open for 24 hours. This means that there is relatively little opportunity for the lights to be dimmed and the covers to be put on refrigerated display cabinets, both energy-saving measures. The consequences are inevitably more energy use.

It may also be the case that the availability of more brands and more variations on particular product types means that more (refrigerated) shelf space is required on which to display them. In other words, more choice leads to larger stores and a larger chilled food area, which in turn leads to greater refrigeration requirements.

Note that the survey was conducted in the mid 1990s and involved a small number of stores. Both these factors may limit the extent to which the findings are applicable to today's retail sector.

Nigel Mortimer and his team now form the Sheffield office of North Energy Associates.