Can coffee grounds drive our cars?

William Atkins
Tuesday, 16 December 2008 20:28

Science - Energy

U.S. researchers report that coffee grounds can be an environmentally friendly biodiesel fuel, by providing plenty of cheap fuel to power all of our motorized vehicles, even the trucks that deliver coffee to Starbucks.


The American Chemical Society’s Journal of Agricultural and Food Chemistry report the findings in its November 24, 2008 article “Spent Coffee Grounds as a Versatile Source of Green Energy.”

The authors of the study—chemical engineers Narasimharao Kondamudi, Susanta K. Mohapatra, and Mano Misra—are all from the Chemical and Materials Engineering Department at the University of Nevada (Reno).

They talk in the abstract to their paper, “The production of energy from renewable and waste materials is an attractive alternative to the conventional agricultural feed stocks such as corn and soybean. This paper describes an approach to extract oil from spent coffee grounds and to further transesterify the processed oil to convert it into biodiesel.”

Biodiesel fuels refer to any non-petroleum-based diesel fuel made from short chain alkyl (methyl or ethyl) esters. These fuels are made by a process called transesterification, which basically turns vegetable oils or animal fats into "green" fuel using methanol and potassium hydroxide as catalyzation agents.

Many different types of oils can be used to make biodiesel fuels, such as soybean, rapeseed, mustard, flax, sunflower, and palm oils.

Among other products used to make biodiesel fuels include animal fats (such as lard, chicken fat, and grease) and algae.

Used coffee grounds contain anywhere from 11 to 20% of oil by weight.

Page two talks about the process to convert coffee grinds to clean-running biofuel.