Coffee grounds could power cars

HANNAH DEVLIN
JUNE 17, 2014
THE TIMES
GROUND coffee could be turned into a sustainable fuel to power vehicles, scientists believe.
The study found that biodiesel can be reliably extracted from the waste grounds of different coffee varieties, from high-quality Arabica to Robusta, which is used to make instant coffee.
The waste produced by an average coffee shop, about 10kg per day, could produce about 2 litres of biofuel.
Chris Chuck, a chemist at the University of Bath who led the research, said: “About 8 million tonnes of coffee are produced globally each year, which could be converted into about 1.3 billion litres of biofuel. The problem is trying to bring all the waste to a central location.”
The global use of diesel is about 4 billion litres each day, he added, meaning that coffee biodiesel would form only a minor part of the energy mix. One option would be for chains such as Starbucks to use coffee-derived biodiesel to power its delivery vehicles, as McDonald’s reuses its cooking oil.
The London company Bio-bean is working with larger coffee producers and plans to set up a waste-processing site in Edmonton, north London, that could process 30,000 tonnes a year.
Fuel can be extracted from coffee grounds by soaking them in an organic solvent that dissolves the oil. The mixture is then filtered to remove the grounds and the solvent is evaporated to leave the oil.
The latest study, published in the journal Energy & Fuels, analysed how the fuel quality varied depending on the type of coffee. The authors tested caffeinated and decaffeinated coffee grounds from 20 regions, and found that between 10 and 20 per cent oil by weight was extracted from the waste.
“The uniformity across the board for the coffee biodiesel fuel is good news for biofuel producers and users,” Dr Chuck said.
Critics say that first-generation biofuels compete with food crops — and converting waste products into diesel could be a more sustainable alternative.
Since 2008, the UK has required fuel suppliers to add a growing proportion of sustainable materials into the petrol and diesel they supply.
In 2010 the BBC program Bang Goes The Theory converted a Volkswagen Scirocco to run from a coffee-powered charcoal boiler. The team planned to drive the car from London to Manchester, powered by about 70kg of coffee — between 25 and 50 times the $65 cost of petrol for the journey.
However, the car broke down in Northampton.
The Times