We can convert the food we bin into energy. But there’s a better, cheaper alternativeby Tristram Stuart / September 23, 2009 / Leave a comment
Published in October 2009 issue of Prospect Magazine
Above: for every tonne of food waste, 110kg of carbon-dioxide emissions can be saved by turning it into 255kWh of electricity
When I arrived in the small town of Ludlow to visit western England’s pioneering anaerobic digestion plant, I knew I was in the right place from the whiff of bins. The smell came from a huge warehouse surrounded by 10-metre tall metal tanks. Heaped up in the loading bay were thousands of bags of decomposing food waste. A closer look provided an insight into the town’s eating habits: half-eaten bananas, cabbages and unopened loaves of bread.
Run by BiogenGreenfinch, this is one of a new generation of anaerobic digestion plants designed to deal with the food-waste crisis while also generating clean, renewable energy. Inside the metal tanks, microbes that thrive in the absence of oxygen break down the organic matter, releasing methane as they do so—just like the microbes that create the bubbles of smelly gas that children stir up from the bottom of muddy ponds. After millions of years of hiding in dank recesses, these microbes have taken centre-stage in the struggle to deal with unwanted food.