Archives for March 2009

As you probably gathered from the title, although this post is technology related, it is definitely off-topic.  However, I found the article interesting, and thought others might as well.  Plus, my brother (an engineering geek) stops by occasionally, so if nothing else, this one is reward for slogging through posts littered with “tech acronym du jour”.

And yes, I did the math.  1 gallon of coffee ground derived biodiesel requires the consumption of 50lbs, approximately 2,250 cups of coffee.  So, if you see a major uptick in my writing output, accompanied by jittery speech, you know I’m doing my part in the “beaning of America”. 

Without (even) further ado, what follows are excerpts from Fuelled by coffee, in the most recent Economist Technology Quarterly.

The basics:

“In the case of coffee, the biodiesel is made from the leftover grounds, which would otherwise be thrown away or used as compost. Narasimharao Kondamudi, Susanta Mohapatra and Manoranjan Misra of the University of Nevada at Reno have found that coffee grounds can yield 10-15% of biodiesel by weight relatively easily. And when burned in an engine the fuel does not have an offensive smell—just a whiff of coffee. (Some biodiesels made from used cooking-oil produce exhaust that smells like a fast-food joint.) And after the diesel has been extracted, the coffee grounds can still be used for compost.”

The accidental discovery:

“The researchers’ work began two years ago when Dr Misra, a heavy coffee drinker, left a cup unfinished and noticed the next day that the coffee was covered by a film of oil. Since he was investigating biofuels, he enlisted his colleagues to look at coffee’s potential.”

Advantages beyond aroma:

“The researchers found that coffee biodiesel is comparable to the best biodiesels on the market. But unlike biodiesels based on soya or other plants, it does not divert crops or land from food production into fuel production.

A further advantage is that unmodified oils from plants, like the peanut oil used by Diesel in the 19th century, have high viscosity and require engine alterations. Diesel derived from coffee is less thick and can usually be burned in an engine with little or no tinkering.”

The math (why we won’t be doing this at home):

“Although some people make their own diesel at home from leftovers and recycled cooking oil, coffee-based biodiesel seems better suited to larger-scale processes. Dr Misra says that a litre of biodiesel requires 5-7kg of coffee grounds, depending on the oil content of the coffee in question. In their laboratory his team has set up a one-gallon-a-day production facility, which uses between 19kg and 26kg of coffee grounds. The biofuel should cost about $1 per gallon to make in a medium-sized installation, the researchers estimate.

Commercial production could be carried out by a company that collected coffee grounds from big coffee-chains and cafeterias. There is plenty available: according to a report by the United States Department of Agriculture, more than 7m tonnes of coffee are consumed every year, which the researchers estimate could produce some 340m gallons of biodiesel.”

If you found this interesting, check out the full article and the reader comments.