Coffee – the dark and invigorating brew that fuels Americans every morning – could soon be providing energy to far more than just our bodies and minds. Engineers at the University of Nevada have proven that used coffee grounds can be effectively used as a source for both biodiesel and solid fuel pellets.
Details of their findings can be found here [PDF].
Every 1,000,000 pounds of coffee grounds can produce just slightly over 13,900 gallons of biodiesel and 847,600 lbs of solid fuel pellets. Since Starbucks generates an estimated 210,000,000 – yes, 210 million – pounds of spent coffee grounds per year in the US, the researchers at the University of Nevada believe that Starbucks could amount to 2,920,000 gallons of biodiesel and 89,000 tons of fuel pellets. This would represent just slightly less than 2.00% (1.986%) of the estimated 147,000,000,000 gallons of diesel fuel required by the US and Europe annually. Now that’s some go juice!
Using coffee grounds as a source for biodiesel doesn’t directly negatively impact the need for converting arable land from foodstuff production into fuel source production. Since coffee grounds are a byproduct or waste product of normal coffee consumption, using them as a biofuel source material avoids the growing problem of the the Food v. Fuel equation.
Coffee grounds can be used as a biofuel source utilizing the well tested and proven transesterification methodology instead of newer and costlier methods. Approximately 15% of the mass of coffee grounds is oil which can be extracted through these methods. Additionally, the high antioxidant content of coffee grounds gives this oil long shelf life since the antioxidants shield the oil from rancidification. This all means that coffee grounds could easily be processed into biodiesel by existing companies that are currently specializing in reclaiming spent vegetable oils for biodiesel fuel.
Coffee grounds, once relieved of their useful oil content, can still provide approximately 84.76% of their mass for solid fuel pellet production. This means that there is only a 0.24% final waste level from converting the coffee grounds to biofuels, and it provides a secondary product to maximize profits since fuel pellets currently sell for $225 USD per ton. This means that Starbucks could generate $20,025,000 (gross) worth of fuel pellets per year in addition to the profits generated from the 2,920,000 gallons of biodiesel they could sell – or use – per year.
Sadly, using coffee grounds as a biodiesel and fuel pellet source material suffers from an in-built problem of inefficiency that is caused by the decentralized nature of the “production” of coffee grounds. Unlike using agricultural byproducts like corn, sorghum, and sugarcane silage – all which are processed in vast quantities at centralized locations, coffee grounds are produced on a coffeehouse-by-coffeehouse basis. This creates both inefficiencies and built-in energy costs in the “harvesting” and production of biodiesel from coffee grounds.
Due to these same inefficiencies and transport energy costs, the use of coffee grounds as a biofuel source material won’t scale downward to individual American household as some other recycling efforts have done. It just won’t be practical for anyone other than entities on the scale of Starbucks, Dunkin’ Donuts, and possibly Caribou Coffee to process coffee grounds for biofuels.
By effectively adding to the value of coffee beans by providing a secondary use for them as a biofuel source material, this may cause coffee growers to raise the price of coffee beans on the international commodities markets. Since coffee is the world’s second most valuable traded commodity, behind only petroleum and is the US’s largest food import and second most valuable commodity only after oil, such as rise in coffee prices could have detrimental effects upon the US economy. This could also generate an economic backlash that could undermine the efforts to further promulgate the Fair Trade programs within the coffee growing nations of the world.
Jonolan’s Conclusions & Opinions
Since 77% of America’s daily consumption of petroleum distillates is in the form of diesel fuel, anything that can make measurable inroads into our requirement for importing the light crude necessary for its productions seems to be a good idea to me.
I’m also very interested in the possible applications for the solid biofuel pellets that can be generated from coffee grounds. With many ecologically sensitives areas – Borneo, Malaysia, and Indonesia to name a few – still being reliant on solid fuels for much of their household energy needs, a ready and importable solid fuel that doesn’t endanger sensitive local ecolocosms seems worth looking into.
For what little it’s worth, I say go for it! Make mine a Vente. 😉