Coffee Biodiesel Could Become Sustainable Fuel Source for Powering Vehicles: Bath Researchers

University of Bath researchers have generated "green" biofuel from coffee waste that could be used to power vehicles in future.

The researchers generated biodiesel from the waste grounds of different coffee varieties - including Robusta (used to make instant coffee) and high-quality Arabica - and caffeinated and decaffeinated forms.

The oil is extracted from coffee grounds by first soaking them in an organic solvent and then using a special chemical process, called "transesterification" to subsequently convert them into biodiesel.

The fuel properties of the finished product vary depending on the type of coffee ground used. The researchers however found that all coffee grounds have standard composition and relevant physical properties, irrespective of the source. Hence, it makes a viable way of generating biodiesel.

"The uniformity across the board for the coffee biodiesel fuel is good news for biofuel producers and users," said Chris Chuck, Whorrod research fellow at the university, Sydney Morning Herald reports.

Researchers said that huge quantities of waste are produced by the coffee bean roasting industries. They claim that around 22lbs (10kg) of coffee grounds generate around two litres of the biofuel.

"Around eight million tonnes of coffee are produced globally each year and ground waste coffee contains up to 20per cent oil per unit weight," Chuck said. "This oil also has similar properties to current feedstocks used to make biofuels. But, while those are cultivated specifically to produce fuel, spent coffee grounds are waste," Belfast Telegraph reports.

Chuck said that about four billion liters of diesel is used every day. Since coffee biodiesel cannot meet the demand, companies like Starbucks, Café Nero and Costa Coffee can use the alternative fuel to power its delivery vehicles.

London-based bio-bean already generates biodiesel and biomass pellets from coffee grounds. The company is currently collaborating with large coffee producing giants to establish a waste-processing site in Edmonton (north London) that could process 30,000 tonnes a year, The Australian reports.

The researchers are now investigating whether other types of food waste can produce biofuels.

The study - "Effect of the Type of Bean, Processing, and Geographical Location on the Biodiesel Produced from Waste Coffee Grounds" - is published in Energy & Fuels.