Food waste and loss is a significant problem throughout the world. According to the Food and Agriculture Organisation of the United Nations (FAO) in Europe, North America and Oceania alone there is a yearly per capita food loss of between 280 and 300 kilograms.
But not everything needs to go to waste. Damaged crops, supermarket products past their ‘best before’ date, as well as scraps from restaurants and hotels, can be used to produce energy thanks to microbial anaerobic digestion.
When microbes digest food, they release methane, a gas that can be used to produce energy. So by placing food waste in big silos, which are oxygen-free, microbes can produce bio-methane that can then be used to generate electricity. Francie Diep explaines how it works over at Popular Science: "The food goes into oxygen-free tanks with particular bacteria species inside that thrive without oxygen. Those bacteria break down the food in many steps; during the last step, bacteria produce primarily carbon dioxide and methane gas."
Sainsbury, the British grocery chain, is already doing this. It partnered with Biffa, an anaerobic digestion facility, that turns food into bio-methane, and is now running it’s Cannock store with waste-generated energy.