Giant leap forward

Fresh produce

Imperial works with Sainsbury's on pilot scheme to reduce energy demand at store

Tuesday 10 July 2012
by Colin Smith

An initiative to reduce the carbon footprint of one of the UK’s largest retailers has taken a leap forward following the successful roll out of an energy efficiency pilot scheme at one of its stores.

Researchers from Imperial College London are working in partnership with Sainsbury’s on a five-year project to develop technologies and solutions that will lower its carbon footprint to help it meet with future climate change legislation. The team has trialled new ways of improving the way that the energy is used such as developing new work processes for keeping the fridges cool and enhancing the heating system in Sainsbury’s Hythe store. Since the start of the project in February 2012, the store has reduced energy demand by 13%, which equates to savings of 60,000 kilowatt hours or 57 tonnes of CO?.

The success of the project will ultimately lead to energy saving schemes being rolled out to more Sainsbury’s stores. This could potentially lead to significant energy savings and a major reduction in Sainsbury’s impact on the environment.

The work involves Imperial researchers from the Faculty of Engineering and the Grantham Institute for Climate Change.

Professor Nilay Shah, Project Director from the Department of Chemical Engineering at Imperial, says:“By streamlining work practices and optimising technology already in use, we’ve shown how energy demand in a supermarket can be reduced considerably. We’ve only focussed on one store at the moment, but if rolled out across the whole of Sainsbury’s, the organisation could considerably reduce its carbon footprint."

Energy demand from the refrigeration system was reduced by 30 percent when the store is closed

Professor Sir Brian Hoskins, Director of the Grantham Institute for Climate Change, adds: “Shoppers are increasingly becoming more conscious of the environmental credentials of the stores in which they shop. They want to know that retailers are doing their best to reduce their carbon footprint. This project is a blueprint for other organisations to emulate and shows that a commitment to the environment can also have a positive effect on the ‘bottom-line through energy savings.”

Paul Crewe, Sainsbury’s Head of Engineering, Sustainability, Energy & Environment said, “We are committed to reducing our operational carbon emissions by 30 per cent absolute and 65 per cent relative by 2020. Our partnership with Imperial College is a great example of academia and industry working together to find innovative solutions to help mitigate our environmental impact, and the results speak for themselves. It’s a great blueprint for the future.”

The Hythe store had a number of low carbon technologies in place such as a biofuel generator and solar panels on the roof, which can be used peak times when energy from the grid is more expensive. The Imperial team optimised these technologies to maximise savings and improved the efficiency of other systems such as refrigeration, lighting and heating, working with contractors and colleagues to develop energy saving practices.

Improving refrigeration processes

The researchers improved the energy efficiency of the refrigerators, which have no doors to enable easy access for customers, but also means that they are big consumers of energy. The researchers installed blinds to trap the cold air and reprogrammed the fridges to defrost after longer intervals. They also raised awareness with staff about the importance of keeping the blinds drawn after the store closes and minimising the time that they are opened when the fridges are being restocked. Energy demand from the refrigeration system was reduced by 30 percent when the store is closed.

Improving the lighting system

The team dimmed the lighting system to save energy and integrated it more effectively with the skylights to maximise the use of daylight where possible. The system now uses 25 percent less energy.

Making the hot food section more energy efficient

The researchers worked with colleagues in the hot food section to conserve energy. They developed a new work routine, involving using appliances only when needed, instead of turning them all on at the start of the shift. This reduced energy consumption in this work area by 10%.

Integrating the heating more effectively

The researchers enhanced the heat delivery in the store from the biomass boiler, which uses waste wood. They improved communication between the biomass boiler and sensors in the store, which signal when more heat is needed, so that system is only generating warmth when required, instead of continuously heating throughout the day. They also improved the performance of the fan system, which distributes heat throughout the store, by reducing the speed at which the fans rotated. Energy demand from the heating and fan systems have been reduced by 45 percent.

The next stage of the project will see the team developing computer models that will enable Sainsbury’s to experiment virtually with configurations so that energy solutions can be tailored to the specific requirements of each store.