Millions of people consume energy drinks and have long done so. Coffee is a very common one. It has long been known that spent coffee grounds still contain a lot of energy, but not the sort that can power humans. Coffee grounds release more heat than wood when they're burned, and there are commercial products that use them this way. There was something called a Java-Log that was once popular with some greens (and may still be, this is a years old memory) and the grounds are compressed and pelletized for use in pellet stoves. It's better than wood in several ways. The oils, which is where a lot of the energy is found, can be extracted and used as a liquid fuel.

. . . the major barrier to wider use of biodiesel fuel is lack of a low-cost, high quality source, or feedstock, for producing that new energy source. 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.

To verify it, the scientists collected spent coffee grounds from a multinational coffeehouse chain and separated the oil. They then used an inexpensive process to convert 100 percent of the oil into biodiesel.

The resulting coffee-based fuel — which actually smells like java — had a major advantage in being more stable than traditional biodiesel due to coffee's high antioxidant content, the researchers say. Solids left over from the conversion can be converted to ethanol or used as compost, the report notes. The scientists estimate that the process could make a profit of more than $8 million a year in the U.S. alone. They plan to develop a small pilot plant to produce and test the experimental fuel within the next six to eight months.

I suspect that the grounds could be used in a CHP system to yield even more liquid fuels as well as a soil amendment that is better than compost in some ways.

It may be worth mentioning that the antioxidants that stabilize the diesel also benefit the original coffee drinkers. Coffee is a wonder food . . . drink, drug, whatever.