Waste Coffee Grounds can be Used to Power Cars, Researchers Say

Scientists have found that waste coffee grounds can be used to power cars.

According to scientists at the University of Bath, oil can be extracted from coffee grounds using a process known as transesterification. In this process, coffee grounds are soaked in organic solvents to remove the oil. This oil is later subjected to several chemical reactions to make biodiesel.

In the current study, researchers looked into whether or not differences in coffee beans affect the fuel properties. For the research, scientists made biofuel from coffee grown in 20 different geographical regions. The study included Robusta as well as Arabica varieties of coffee.

The study found little to no differences in properties of biofuel made from different coffee bean varieties, meaning that all coffee bean waste can be used to make fuel.

"Around 8 million tonnes of coffee are produced globally each year and ground waste coffee contains up to 20 per cent oil per unit weight," said Dr Chris Chuck, Whorrod Research Fellow from the Department of Chemical Engineering at the University of Bath.

"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. Using these, there's a real potential to produce a truly sustainable second-generation biofuel," Chuck said in a news release.

According to the researchers, coffee biodiesel would contribute to a small part of the energy mix. Nevertheless, small establishments such as coffee shops can use the technique to power their delivery vehicles.

Coffee bean roasting industry also throws away several tonnes of defective beans. These establishments could also use the coffee grounds to make biofuel, researchers said.

The study is published in the journal ACS Journal Energy & Fuels. The team at the University of Bath is looking at other feedstocks to see which one can be made into biofuel.

This isn't the first time that coffee grounds have shown promise as biodiesel. Recently, a coffee-powered car broke a Guinness World Record by reaching 65 m.p.h.