Responsible shopping

A new Tesco store in Norfolk is the first of its kind, and one of the most energy-efficient superstores in the country. Tom Idle had a browse around

For the past four months, staff at the Tesco store in Diss, Norfolk, have had to come to terms with their new place of work. The energy-efficient superstore, which has received a lot of interest from energy champions and interested retailers, is certainly not your average place to shop.

For a start, there are the huge wind turbines, which dominate the shop’s façade. Then there are the bright green signs on the shop floor, which indicate to the public what energy efficient measures have been taken – such as explaining how the wind turbines they’ve just seen in the car park help to power the checkouts they’re about to use.

But it’s not until you go behind the scenes at a place like this that you realise the lengths the company has gone to in implementing and, in some cases, trialling new technology and environmentally responsible measures.

In a drive to reduce energy use and save money, the company decided to pool all of its energy-saving projects in one location to assess what cumulative effect they could have. Bosses hope the Diss store will use 20% less energy than an equivalent-sized store. On average, a similar-sized shop will use about 3 million kWh a year. For Diss, this will be reduced to 2.4 million kWh – a saving which is enough to power 65 houses for a year.

Despite having to adopt new strategies of operation, staff at the Diss site have embraced their new place of work with enthusiasm and are happily explaining some of the modifications to customers on the shop floor.

I met up with Store Manager Paul Savory, who explained each of the measures that have made his shop one of the most efficient in the country.

Sandwich cabinet

“This is a big step for us because it’s the first time we’ve tried to sell sandwiches from behind closed doors. This unit has a big impact because it is right by the entrance, and this is where you get a lot of air turbulence with people walking in and breaking the air curtain. So this fridge

notoriously wastes an enormous amount of energy without those doors on. The company has now got intentions of retrofitting some sites with these, and working out just how much energy is being saved.”


“All of the chillers are new, revised with an energy-efficient design. The base is higher than normal and comes out further. The idea is that it catches the cold air, rather than allowing it to just spill on to the floor and be wasted.

“And then there’s the pull-down screens, which we use when closed overnight. The thing that we’ve had to change is the way we replenish our store. Normally, you could just bring stuff in from a delivery. We have to think a bit smarter now. Any cold air that is wasted from the chillers is collected and drawn upwards, and that’s used in the cooling of the store. There’s no heat reclaim but that’s something they are looking at for the future. It’s highly expensive at the moment.”


“The ovens in here turn themselves off after about half an hour but they retain their heat because of the thick walls. At night, we don’t have to remember to turn them off. Some of our ovens are split into sections, so if you are doing a half-bake, you don’t have to have the whole oven on, wasting energy. Ten percent of the energy used in the store is by the bakery. The idea is that we have hot bread on sale throughout the day – you can’t do that by just baking in the morning. So, we need to bake little and often.”

Wind turbines

“The store doesn’t solely depend on wind energy, and is connected to the grid. But when the wind gets to the right pitch, all of the turbines fire-up and electricity is fed straight into the mains. With all of them running, they generate enough electricity to power all of our checkouts.”


“In the ceiling, there are ‘north lights’. These are rows of transparent-plastic, which slope to stop the sun from the south getting in and giving us a greenhouse effect, but still maximising the natural daylight from the north. As the light in the store gets brighter, there are sets of lights that will go off. On clear, bright days, we run on natural light.”

What measures have been taken at Diss?

  • Five roof-fitted wind turbines generate enough electricity to power all 15 checkout tills and conveyor belts at maximum output
  • A cold-air retrieval system extracts and pumps excess cold air generated by the refrigeration into other areas of the store that need to be cooled down. This reduces the need for air-conditioning by recycling the already cooled air
  • Modified shelf and storage designs in chilled areas, such as glass doors on the sandwich cabinets, reduce cool air loss. Cabinets with a canopy above the shelves, and dairy and milk cabinets with lips below the shelves, reduce the rate that cool air escapes
  • Three north lights in the roof allow the maximum amount of light in, reducing the amount of electrically generated light needed, while not overheating the store
  • ‘Sun pipes’ have been installed in staff offices, facilities and corridors, which reduce the amount of artificial lighting needed
  • Photocell lights in the loading areas are triggered by low external light
  • Light movement sensors ensure lights in offices and other staff areas are only on when needed
  • Bakery ovens are more energy efficient, and staff have been trained in the most effective use of them

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