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Sainsbury’s supermarket to be powered entirely by its own food waste

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July 23, 2014

Waste like this should meet all of a UK grocery store's electrical needs (Photo: Shutterst...

Waste like this should meet all of a UK grocery store's electrical needs (Photo: Shutterstock)

It's an unfortunate fact that every day around the world, supermarkets throw out tons of food that has spoiled before it could be purchased. While it would be best if that spoilage could be avoided in the first place, British grocery chain Sainsbury's is taking what might be the next-best approach – it's about to start using that unsellable food to power one of its stores.

Here's how the system should work ...

First of all, produce that's a little past-its-prime but still edible is donated to charities, while food that's a little older is given to zoos or used in the production of animal feed.

The stuff that's truly rotten, though, is picked up from Sainsbury's stores across the UK by the same trucks that deliver the fresh food every day – so the trucks aren't making special trips just to pick up the waste. They return with it to the central Sainsbury's depot, where it's subsequently picked up by trucks from the Biffa waste management company.

These trucks deliver it to a Biffa-operated plant in the town of Cannock, where it's fed into an anaerobic digester. Within the zero-oxygen environment inside that digester, bacteria break down the waste to produce bio-methane gas. That gas is then used to produce electricity at the plant.

From there, the electricity is fed to Sainsbury's Cannock store via a 1.5 km (0.9 mile)-long cable. That electricity should meet all of the store's day-to-day needs, allowing the building to operate independent of the national electrical grid. Any extra electricity that's not needed by the store, however, will be fed into that grid.

One byproduct of the anaerobic digestion process is a substance known as digestate, at least some of which can be used as a fertilizer by local farmers.

According to Sainsbury's, it's already the UK’s largest retail user of anaerobic digestion, and has been diverting all of its stores' food waste from landfills since last June.

There's currently no word on when the Cannock program will begin.

Source: Sainsbury's via Popular Science

About the Author
Ben Coxworth An experienced freelance writer, videographer and television producer, Ben's interest in all forms of innovation is particularly fanatical when it comes to human-powered transportation, film-making gear, environmentally-friendly technologies and anything that's designed to go underwater. He lives in Edmonton, Alberta, where he spends a lot of time going over the handlebars of his mountain bike, hanging out in off-leash parks, and wishing the Pacific Ocean wasn't so far away.   All articles by Ben Coxworth
6 Comments

I can understand that food would invariably go to waste at some stage within a supermarket..... BUT....why would a supermarket still keep "stuff that is truly rotten" on its premises??????....and then transport this truly rotten garbage which will no doubt be bacteria and fungi infested in the SAME trucks that are delivering FRESH products...hmmm...just to save fuel....so the question is....how well contained are the rotting stuff when they are packed into the trucks AND how well sanitized are the trucks once they deliver the rot and BEFORE they load the good stuff. In my book there's just too much room for transmission of fungi and bacteria in this process...maybe that is the reason why the good food may rot quicker...just a thought!!!

ASHDIL
24th July, 2014 @ 01:47 am PDT

the other issue is whether this creates an incentive to let unsaleable food become truely rotten i.e. reduce the amount going to charity and animal feed, as there is now a better price achieved by converting it to electricity.

JPAR
24th July, 2014 @ 08:14 am PDT

Good. This truly means "food doesn't go wasted". There should be no waste in the first place, recycle it into valuable products.

Fretting Freddy the Ferret pressing the Fret
24th July, 2014 @ 02:34 pm PDT

Sounds like they solved the cost effective barrier and hopefully they add broken cereal boxes and such as well. But they should offer to pick up the waste biomatter from other companies as well.

@ ASHDIL

The pickup of the waste is probably more often and hosing out the trucks with a bleach solution is not difficult.

Slowburn
24th July, 2014 @ 09:42 pm PDT

If done on a local basis this would be a good idea. I can't believe that there is much net gain in energy if 100's of truck loads of organic matter is being transported 1000's of miles around the country in order to generate power 'some' power. I'd like to see the numbers, though i.e. how much diesel is used shipping the waste to cannock (including the extra diesel used for a full return trip of the Sainsbury's lorries rather than empty) and same for all the Biffa trucks and the energy used running of the Cannock plant etc etc. Then there's the cost of it all… more number , please! MW

Martin Winlow
26th July, 2014 @ 01:21 am PDT

@ Martin Winlow

The energy cost of moving the biomatter to the digestion tank is almost entirely the difference in mileage between loaded and unloaded trucks and that is not that much particularly because the amount of waste is trivial compared to the full load.

Slowburn
26th July, 2014 @ 08:41 pm PDT
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