Sainsbury’s has opened a store extension in Durham today which although increasing the building’s square footage by 50% has at the same time reduced the amount of energy it uses by 10%.

The reduction has been brought about by a number of technologies including onsite renewable power generation and what Sainsbury’s described as “ground-breaking” refrigeration technology. As the energy efficiency of the building is so much higher, and renewable energy is generated on-site, the carbon generated in building the extension will be neutralised after just two years.

Sainsbury’s commercial director Neil Sachdev said: “It seems rather counterintuitive, but by adding this space to the building, we are actually reducing its overall environmental impact and we regard this as a great feat and a sign of things to come. We feel it is important to establish leadership in this area because in the long-run, it’ll reduce our costs and put us in a better position against our competitors.”

The extension will generate its own renewable energy through a biomass boiler that burns wood pellets to generate electricity and heat. Sainsbury’s is the first retailer to use this kind of boiler, which reduces the amount of energy drawn from the grid and uses waste wood that would otherwise have been sent to landfill.

In addition, this will be the first extension to use CO2 refrigeration, following Sainsbury’s announcement in November that it was beginning a planned phase out of Fgas. The move will reduce the company’s carbon footprint by around a third.

The re-modelled store will harvest rainwater, which will help to bring about a 50% reduction in mains water usage. The extension will be constructed out of wooden panels rather than steel or glass, to reduce the carbon impact further.