The UK supermarket chain Sainsbury's is setting an example in sustainability by transforming its own food waste into energy. A store in Cannock, in central England, is now run entirely on electricity generated from its own recycled refuse, marking the first time a major retailer is not reliant on the national grid for its power.

Here's how it works: Any food that can't be donated to local charities for human consumption or turned into animal feed is transported to a nearby anaerobic digestion (AD) plant run by waste management company Biffa. The food waste is converted into biomethane gas, which is used to power the store.

A 1.5-kilometer cable (that's less than a mile, for you metric-phobes) connects the processing plant to the Sainsbury's, thus very literally closing the loop on food recycling.

This remarkable model may not work everywhere, but it certainly offers grounds for optimism.

As Richard Swannell, a director at Wrap, a government-funded organization that promotes recycling and sustainable business, told the BBC, "There are now 60 AD plants recycling food waste, which can process up to 2.5 million tons of food waste per year and generate enough renewable electricity to power a city three times the size of Cannock."