A supermarket outlet in the UK is capable of operating off grid, using rotten produce to generate electricity.

A Sainsbury’s outlet in the English town of Cannock has converted to the usage of bio-energy generated with recycled food as part of efforts by the British supermarket chain to raise the sustainability of its operations and reduce its landfill waste.

Outdated produce is first taken from Sainsbury’s stores around the UK and transported via lorry to an advanced anaerobic digestion (AD) facility in Cannock, operated by waste management company Biffa. The program makes use of any produce that has been sitting on the shelves of Sainsbury’s outlets too long to be consumed safely by humans or converted into animal feed.

After arriving at Biffa’s Cannock facility, the food waste is then deposited in giants silos that break it down in a manner akin to the human digestive system, leading to the production of bio-methane gas.

This biogas is then used to generate electricity at Biffa’s AD plant, which is conveyed directly to the supermarket via a 1.5-kilometre power cable that connects the two sites.

By using outdated produce that would otherwise go to waste, the AD facility is capable of generating enough electricity to supply all of the Cannock supermarket’s power needs, enabling the store to go completely off grid for day-to-day operations.

In addition to generating copious amounts of useable power, the Biffa facility also produces digestate as a byproduct, which can be utilised by regional farms as a fertiliser.

The scheme is part of efforts by Sainsbury’s to dramatically raise the efficiency and sustainability of its UK-wide operations. In June 2013, Sainsbury’s managed to meet its sustainability target of recycling all store waste, removing the need to deposit it in landfill sites.

All of the general waste produced by the supermarket chain is now recycled via donations to charities for consumption by the needy, conversion into animal feed, or use as biofuel for anaerobic digestion plants.

These efforts have made Sainsbury’s the biggest retail user of anaerobic digestion in the UK, generating enough power each year to supply the needs of 2,500 households.

Biffa has extensive experience in the conversion of food waste into bio-fuel. Its Poplars site in Staffordshire is the largest operating AD plant in the UK which runs on source segregated food waste, and is licensed to process 120,000 tonnes of food waste a year.