Run that Car on Coffee!

Run that Car on Coffee!

I’ve been joking for years that I should shoot some of my favorite high-octane coffee into the gas tank of my sluggish minivan and give it a little bit of get-up-and-go. Seem I may have been on to something. According to an article in the ACS’ Journal of Agricultural and Food Chemistry, waste coffee grounds can be used to make biodiesel fuel for powering cars and trucks. According to the report, waste coffee grounds are a “cheap, abundant and environmentally friendly source of biodiesel fuel”.

While there are a lot of folks out there that use spent coffee grounds in compost or as a soil conditioner, far more used coffee grounds end up in the trash and in landfills. That’s a huge waste, if the researchers are right. Researchers Mano Misra, Susanta Mohapatra and Narashimharao point out that one of the major barriers to using biodieself fuel on a wider basis is the lack of high quality, low-cost feedstock for producing a new energy source. In fact, one of the biggest criticisms of most biodiesel sources is that using them – soybeans, corn, rapeseed and palm oil – reduces our food sources and will result in raising the prices of feed and ultimately, the cost of meat.

Spent coffee grounds, on the other hand, aren’t much used for anything else. No one is raising cattle on old coffee grounds. And those grounds, says the study, contain just about the same amount of oil by weight as any of the traditional feedstocks that have been used to make biodiesel fuels.

No one has quite measured how much coffee grounds are thrown out each year, but we do know that coffee growers grow and sell over 16 billion pounds of coffee each year. The scientists estimated that using up some of those spent coffee grounds could add about 340 million gallons of biodiesel to the world’s fuel supply – though they neglected to note whether that’s per day, per year, per week or per … well, town, maybe?

Whichever it is, they also learned that coffee grounds create a more stable biodiesel fuel than tradiitional sources because of the high content of antioxidant – I guess our bodies aren’t the only thing that like antioxidants. In addition, the leftover solids can be converted to ethanol, adding even more alternative fuel to the market – or they can be used as compost, just like the coffee grounds are. They learned all this by collecting spent coffee grounds from a “multinational coffeehouse chain” – most likely code for Starbucks – and separating the oil from the beans. They then used an inexpensive process to convert every last bit of the oil into biodiesel.

The report estimates that their process has the potential to make more than $8 million in profit a year in just the U.S. They intend to develop a small plant to produce and test the fuel within the next six to eight months. One additional bonus to the coffee ground biodiesel fuel – it smells like… coffee! Go figure.


  1. I have on hand more than 200 tons of spent coffee with access to an almost unlimited future supply.We are composting it now and hope to find interested parties to process this free resource into bio diesel.Interested parties may contact me at my email address.

  2. This is certainly a very interesting feedstock, as this does not compete with food for land. Neither does it require additional resources because it is wast anyway. However the collection and trucking to central processing plants my spoil the overall carbon footprint a bit. There is a big advantage, if you grow coffee, and make biodiesel at the same spot, such as in brazil.

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