Media playback is unsupported on your device Media caption Emma Simpson reports on how one supermarket is putting food waste to good use

A Sainsbury's superstore is being powered directly by its own food waste, the first time a retailer has come off the National Grid to power a store.

The store at Cannock, Staffordshire, already sends all its food waste to the UK's largest anaerobic digestion plant.

The facility, run by Biffa, turns food waste into bio methane gas, which is then used to generate electricity.

But now, a 1.5km cable has been installed linking the plant to the nearby superstore.

This allows Sainsbury's to receive electricity directly from the plant.

"Sainsbury's sends absolutely no waste to landfill and we're always looking for new ways to re-use and recycle," said Paul Crewe, head of sustainability at Sainsbury's.

"We're delighted to be the first business ever to make use of this link-up technology, allowing our Cannock store to be powered entirely by our food waste," he said.

Sainsbury's is not the only grocer that gives surplus food to charities, or failing that, sending it for use in animal feed.

But that still leaves thousands of tonnes of food waste to deal with. It's collected from every store using Sainsbury's delivery lorries.

Media playback is unsupported on your device Media caption One third of all food produced is wasted, the UN estimates

Financial sense

Eventually the vast majority of it ends up at Biffa's anaerobic digestion plant. The energy generated gets transferred into National Grid and is enough to power the equivalent of two-and-a-half thousand homes a year.

Sainsbury's said it's not only good for the environment, it makes financial sense too given the cost of sending waste to landfill.

It took two years of planning for this project to come to fruition. It may not be practical for other big retailers or businesses to copy, but it is eye-catching. Sainsbury's has closed the loop on food recycling in a way that's never been done before.

According to Wrap, the Government funded body that promotes recycling and sustainable business, the Cannock anaerobic digestion plant is part of a quiet revolution now underway in the UK.

"There are now 60 AD plants recycling food waste, which can process up to 2.5 million tonnes of food waste per year and generate enough renewable electricity to power a city three times the size of Cannock," said Richard Swannell, a Wrap director.

"So when you recycle your food waste at home, at school or at work, it is being put to great use delivering a more sustainable future for us all."