Researchers are reporting they have successfully made a high quality biodiesel from spent coffee grounds. They estimate that the coffee ground biodiesel industry could generate as much as $8,000,000 in profits annually using waste from US Starbucks stores alone.
One of the main limits to the acceptance of biodiesel as an alternative fuel is its price premium above regular diesel. To bring the price of biodiesel down, the industry uses as much waste material from other industries as possible to make it — such as used fryer oil and animal fats from poultry processing.
In holding with the idea of cheap biodiesel feedstocks, a team of researchers in the Chemical and Materials Engineering Department at the University of Nevada figured that maybe spent coffee grounds would fit the bill too.
And boy do they ever. Not only do spent coffee grounds have a relatively large amount of oil (about 15% — almost all of which can be converted into biodiesel using standard methods), biodiesel made from the grounds has a long shelf life due to the large amount of antioxidants in coffee. Antioxidants slow the process of rancidification.
There’s a bonus too: at the end of the biodiesel extraction and conversion process, the leftover grounds can be turned into fuel pellets for wood stoves and boilers, closing the waste loop (or at least putting most of the carbon and nutrients that had recently been used by the plant to grow back into the atmosphere where they can again be used by plants to grow).
Given that Starbucks generates 210 million pounds of spent coffee grounds per year in the US, the researchers calculate that it could amount to 2.92 million gallons of biodiesel and 89,000 tons of fuel pellets. After taking out operating costs, and assuming a sale value of $4.50/gallon of biodiesel and $225/ton of fuel pellets, that amount equals just over $8 million of profits per year (view calculations).
Conducting my own calculations, even at $3/gallon for biodiesel, profits would be in the $4 million per year range.
Anybody in Seattle listening?