At the end of the film Back to the Future something amazing happens. Doc Brown appears in his time-travelling DeLorean car and, as he talks excitedly to Marty McFly, he starts pulling things out of a bin.
“I need fuel,” he says, before dropping a banana skin and other bits into a hopper on the back of the car.
There is no time machine, but in Bangalore, India, Shell is building a pilot plant that will turn waste – even discarded household junk – into petrol or diesel that can power cars.
“The quest to turn rubbish into energy is this century’s alchemy,” says Dr Alan Del Paggio, vice president of CRI Catalyst Company, the Shell business which licenses the technology worldwide. “Only, it’s not magic; it’s simple chemistry.”
There is certainly no shortage of waste – whether from households, agriculture or forestry.
A recent report for the World Bank warned that by 2100 the world’s growing urban population will be producing three times as much domestic waste as it does today. The study predicted the amount of domestic waste will rise from around 3.5 million tonnes every day in 2010 to more than 6 million tonnes by 2025 – about the weight of the Great Pyramid in Giza, Egypt – and to 11 million tonnes by the turn of the century.