It's not often you get an electric shock while opening an envelope, but that is effectively what happened to c-store owners across the country when they received last year's energy bills.
The hike in fuel prices took everyone by surprise, throwing carefully prepared budgets into chaos. Suddenly the store's lighting, heaters, air conditioning, chilled displays and freezers took on the look of energy-hungry monsters, eagerly sucking profits out of the business.
In recent weeks the power suppliers have shown some mercy with reductions in their rates, but with no prospect of a return to the prices of 12 months ago, and pressure on sales margins unlikely to ease any time soon, the retailer's response has to be to look at the running costs of electrical equipment.
It has been calculated that a 25% reduction in energy consumption is equivalent to a 5-10% increase in sales; a pretty convincing reason for action in itself, even without the environmental benefits of reducing power usage.
Most c-stores offering a full range of fresh and chilled goods have as many temperature zones as a small planet. Frozen foods and ready meals require a sub-zero cabinet, while chilled display cases keep fresh food and bottled drinks at optimum temperature. In many cases this requirement for cooling leaves a chill in the air - a result of cold air escaping from cabinets and flowing across the shop floor. This phenomenon of cold aisles is not only a terrific waste of energy, it is also likely to restrict the time customers spend in the section, maybe even in the store.
The Co-op Welcome (CWS) store at Sneinton Dale, Nottinghamshire, offers a glimpse of the energy-conscious future. For the past eight months it has been a guinea pig for a new piece of equipment that provides the store's heating, refrigeration and air-conditioning needs.
"Before we had the new installation there were times when you used to be able to see your breath in front of your face in here," says Brett Iantosca, duty manager at the store. "Customers used to complain about how cold it was, and you could see that they would hurry through the aisles and pick up what they needed without stopping to browse. It was difficult for the staff, too - they would stand behind the tills with their coats on, which isn't the most welcoming sight."
The solution at the time was to install infra-red heaters around the walls of the store, but it had limited success; not only did the heaters cause some product on the higher shelves to suffer, but they also meant that the store was, in effect, paying to re-heat air it had already paid to cool.
On top of that there was an electric overdoor heater, intended to provide an air curtain between the store and the street, but all too frequently it was used as additional heating for staff and customers.
Faced with irritated customers and out-of-control power consumption, Co-op Group technical consultant Bill Watson approached Daikin UK, one of the country's largest air conditioning manufacturers. Air conditioning is associated in most people's minds with cooling - keeping people comfortable in offices and shops - but in recent years the technology has outgrown this limited view. Sophisticated systems like Daikin's Conveni-pack can heat as well as cool, and cleverly reuse the heat rejected by chilled displays to warm other parts of the store. To put it in terms any retailer would recognise, it's two for the price of one.
Daikin's Mike Kocurek says that the Conveni-pack, although new to Europe, is well established in Japan. "This technology is perfect for c-stores about the 3,000sq ft mark because they have a unique mix of energy demands in a confined space, but are too small to merit the expense of the kind of equipment used in supermarkets," he adds.
A store of this size might once have had a refrigeration plant on the roof and an air-conditioning condensing unit in the yard, and if you were to hold a hand over the fans of either you would find a warm current of rejected heat being released into the atmosphere. Recent systems not only combine these two functions, but also reclaim that waste heat and reuse it to provide space heating, a warm air curtain over the door, and even a source of hot water.
In Sneinton Dale, the Conveni-pack operates mostly in heating mode. Fabric ducts in the ceilings distribute the air, with nozzles directing it into the aisles so it is the shoppers who feel the benefit while the food on the shelves stays chilled. If the temperature rises, the kit will quietly and efficiently switch to conventional air conditioning.
Kocurek says: "The Co-op store is already seeing significant savings in energy costs in the six months since installation, compared with the running costs of the conventional system used over the same period in 2005. Even during the high summer temperatures last August, the weekly electrical consumption was a steady 5,000kW/h a week, compared with 6,000kW/h a year earlier."
That saving could mean as much as £350 off the monthly bill. And keeping power consumption down has an additional benefit; higher demand for electricity can sometimes mean the normal supply to a store cannot cope, and a three-phase supply involving a sub-station may have to be installed - an extra expense and inconvenience. Watson points out that in the case of a recently completed installation at a second Co-op store, the new system avoided the need for a power upgrade which would have cost £15,000.
Although he is very impressed with the results at Sneinton Dale, and plans to convert further premises, Watson advises potential investors to choose their installer carefully as the technology is very specialised and installing and maintaining it requires a specially trained contractor.
The equipment is now available to new and refurbished stores. If the initial cost is higher than conventional systems, it is a pill worth swallowing. A government scheme to encourage the use of energy-efficient equipment offers tax allowances to purchasers of the Conveni-pack, and this, with the improved power consumption, should return the initial cost in less than three years.
Watson adds: "The new system certainly appears to have solved the 'cold store' problem, and energy consumption is down. It has also created more space in the delivery areas and, as it's much smaller than the previous installation, has enabled us to overcome planning issues and noise sensitivities. It's still early days, but the system appears to be a resounding success."
The art of cool
Anyone who has studied the laws of thermodynamics - and who hasn't? - knows that you can't make or destroy energy. You can only move it around.
Refrigeration and air-conditioning equipment, and even the humble domestic fridge, cool by removing heat from the area to be chilled using a vapour compression cycle.
This heat is usually expelled from a condenser and thrown away, but as awareness of the value of energy becomes more widespread, system manufacturers have realised that wasteful practices like this are no longer acceptable. Their most recent equipment reuses this heat in other parts of the building, so hot air extracted from a restaurant kitchen, for example, might be recycled to warm up the diners in the next room, or even to help heat a water tank.
In a c-store, the same process can keep one area, such as a run of chilled or frozen display cabinets, cool - and another nice and warm, such as the entrance or till area.