Old Coffee Grounds a New Source of Auto Fuel?

Researchers at the University of Nevada-Reno say that old coffee grounds could potentially be transformed into 340 million gallons of biodiesel a year, according to a report in the ACS Journal of Agricultural and Food Chemistry (and summarized here by Green Car Congress.)

Oil accounts for around 11 percent to 20 percent of the content of spent coffee grounds. When dried and mixed with solvents, the researchers found they could extract most of the oil. It’s a high quality oil too that’s somewhat stable. That’s important in biodiesel. Some biodiesels, like those derived from animal fats, sometimes have low smoke points.

The world consumes 16.34 billion tons of coffee a year.

Although bigger than most fish tanks, 340 million gallons a year is a small amount of oil. The world consumes around 85 million barrels of oil a day right now and there are 42 gallons of crude oil in a barrel (which means 3570 gallons a day) Thus, if you started on January 1 and tried to run the world of coffee biodiesel, we’d run out while most New Year’s Eve parties are still going. But still conservation helps and every little bit count.

And for local production, it could be great. Lots of coffee gets gulped in Reno. (I think there was a coffee machine in my fourth grade classroom.) The researchers did not harvest their grounds from the Lucky Forest Snack Bar at Fitzgerald’s or some other classic Reno locale. They went to Starbuck’s.