Coffee power

Researchers at the University of Nevada-Reno claim that waste coffee grounds can provide a cheap, abundant, and environmentally-friendly source of biodiesel fuel for cars and trucks.

The major barrier to wider use of biodiesel fuel is lack of a low-cost, high-quality source, or feedstock.

Spent coffee grounds contain between 11 and 20 per cent oil by weight - about as much as traditional biodiesel feedstocks such as rapeseed, palm, and soya bean oil.

The used or 'spent' grounds remaining from coffee production often end up in the rubbish or find use as soil conditioner.

The Nevada scientists estimate, however, that spent coffee grounds can potentially add 340 million gallons of biodiesel to the world’s fuel supply.

To verify it, the scientists - Mano Misra, Susanta Mohapatra, and Narasimharao Kondamudi - collected spent coffee grounds from a multinational coffeehouse chain and separated the oil.

They then used an inexpensive process to convert 100 per cent of the oil into biodiesel.