The Next Great Biofuel – COFFEE

Guest writer MAC’s coffee addiction may actually be good for the environment. 


My friends and colleagues could well argue that I am already powered by coffee, judging by the amount of the stuff I consume during an average working day. But now comes the announcement that scientists have perfected a way of making biodiesel from the coffee grounds that we so carelessly discard every day.

The waste from the world’s continuously expanding appetite for “coffee shop coffee”, such as Starbucks, Seattle’s Best and Costa Coffee to name just three, could turn out to be the next big energy providers – big enough to rival the giant oil companies if the process to extract nearly two million tonnes of fuel from the beans that we currently throw away can be scaled up.

According to Rhodri Jenkins, PhD student from the University of Bath, where the study is being conducted, the average coffee shop produces about 10 kilogrammes of waste per day, an amount that can be converted into two litres of biofuel – a relatively small amount but perhaps enough to power local deliveries or to power a truck to collect all of the spent coffee grinds and take them to a central processing plant for conversion to fuel.

Apparently, there is also a large amount of waste in the coffee bean roasting industry, with defective beans being thrown away. The process to convert this waste product to a usable one is supposedly relatively simple with the grinds being soaked in an organic solvent followed by a process known as “trans-esterification” that converts it into biodiesel. Sounds like the “tranmogrifier” from Calvin and Hobbes to me.


Researchers found that the fuel quality of the finished product vary according to the type of coffee used, which to me seems a bit obvious when I compare the effects of a double espresso and a standard after-dinner coffee on my state of personal “twitchiness”. All coffee tested had the ability to produce biodiesel, though, irrespective of the region it is produced in and also if it was decaffeinated or not.

Dr Chris Chuck, one of the researchers, said, ‘Around 8 million tonnes of coffee are produced globally each year and ground waste coffee contains up to 20% oil per unit weight. This oil also has similar properties to current feedstock 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.’ Which is of course a good thing as it means our future energy expenditure will not be done at the expense of making someone else hungry.

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