Spent coffee grounds contain between 11 and 20 percent oil by weight. That’s about as much as traditional biodiesel feedstocks such as rapeseed, palm, and soybean oil.
Growers produce more than 16 billion pounds of coffee around the world each year. The used or “spent” grounds remaining from production of espresso, cappuccino, and plain old-fashioned cups of java, often wind up in the trash or find use as soil conditioner. The scientists estimated, however, that spent coffee grounds can potentially add 340 million gallons of biodiesel to the world’s fuel supply.
U.S. diesel usage is around 40 billion gallons per year for on-road transportation, so at 340 million gallons, biodiesel from coffee grounds represents just a drop in the coffee cup. I wonder if it makes your exhaust smell like a Peet’s Coffee shop?
Oh Snap! Now some German scientists have (in effect) taken a swing at Stanford professor Mark Z. Jacobson, who concluded in a recent paper that biofuels are a bad policy direction (see summary post here).
Their key discovery is that by reforesting land that has been “degraded by human use in historical times”, they found:
… the global energy demand projected by the International Energy Agency in the Reference Scenario for the year 2030 could be provided sustainably and economically primarily from lignocellulosic biomass grown on areas which have been degraded by human activities in historical times.
Olive stones can be turned into bioethanol, a renewable fuel that can be produced from plant matter and used as an alternative to petrol or diesel. This gives the olive processing industry an opportunity to make valuable use of 4 million tonnes of waste in olive stones it generates every year and sets a precedent for the recycling of waste products as fuels.
The difference between fuel from corn and fuel from olive pits? The pits otherwise are waste, while corn grown for fuel displaces crops grown for food.
I think Michael Pollan would approve. What do you think? swanksalot