Waste coffee grounds are being mooted as the latest sustainable source of biofuel.
Researchers from the University of Bath have discovered that all kinds of coffee are suitable for use, and could produce as much as two litres of fuel from just around 10kg of waste – roughly the amount of waste a coffee shop will generate in a day.
The scientists made biofuel from coffee produced in 20 different, including caffeinated and decaffeinated forms, as well as Robusta and Arabica varieties. All were found to be up to the task, with little in the way of variety of composition, making them well suited for biofuel production.
While production of biofuel from waste coffee is unlikely to reach any significant scale, the scientists think that coffee shops could produce enough to run their own delivery vehicles on the fuel. These same delivery vehicles could be used to collect spent coffee grinds and take them to a central biodiesel production facility to be processed.