Looking for a spare 340 million gallons of biodiesel? Waste coffee grounds can provide a cheap, abundant, and environmentally friendly source of biodiesel fuel for cars and trucks. Spent grounds contain 11-20 percent oil by weight—about the same as rapeseed, palm, and soybean oil. Growers already produce more than 16 billion pounds of coffee yearly and the spent grounds generally wind up in the trash.
To see if that oil from those grounds is worth putting into your diesel tank, researchers from the U of Nevada collected separated the oil from the grounds and used an inexpensive process to convert 100 percent of it into biodiesel.
The result: a coffee-based fuel that actually smells like java. Mmmm. Plus it’s more stable than traditional biodiesel due to the coffee’s high antioxidant content. The solids left over from the conversion process can be converted to ethanol or used as compost. The researchers estimate the process could make a profit of >$8 million a year in the U.S. alone. Worldwide it could produce 340 million gallons of biodiesel annually. The team plans to develop a pilot plant in the next eight months.
The study appears in the American Chemical Society’s Journal of Agricultural and Food Chemistry. Drink it up. Wake up your car.
Julia Whitty is Mother Jones’ environmental correspondent, lecturer, and 2008 winner of the PEN USA Literary Award, the Kiriyama Prize and the John Burroughs Medal.
