Many of us depend on coffee to fuel our early morning meetings, midafternoon slumps or all-night study sessions. These days, the words “coffee” and “fuel” are half-jokingly synonymous. More than 9 million tonnes (almost 10 million tons) of the bean are produced annually around the world and, once we brew it, an awful lot of waste is created. The vast majority ends up in landfill.
Researchers in South Korea, however, have discovered a way of using coffee ground waste as a fuel in a far more literal sense. In a study in Nanotechnology, they report using coffee waste to produce a carbon material full of small pores, which increase the surface area, known as “activated” carbon. This new material is capable of absorbing and storing methane and hydrogen, both of which can be used as fuels.
While the ability to store these fuels from such a cheap material is a great step toward making this technology more viable, it also provides an environmental advantage: methane is a harmful greenhouse gas.
This is by no means the only use for waste coffee grounds. As a relatively pure and essentially free waste stream, scientists, engineers, and entrepreneurs have looked into various ways of putting it to use.
Burn Coffee for Low-Cost Fuel
For a few years now, Nestlé has been using waste coffee grounds from its instant soluble coffee production as thermal fuel. It currently uses coffee to cook the food it produces in more than 20 factories globally, displacing more than 800,000 tons of coffee grounds each year that would otherwise go to landfill.
In a more specific enterprise, the London-based company Bio-bean is trying to turn waste from local instant coffee producers (nearly 200,000 tonnes in London and southeast England alone) into biomass pellets for power generation, as well as residential heating using trendy biomass burners. These beans burn more cleanly and contain 50 percent more energy than traditional wood pellets. However unlike Nestlé, Bio-bean first removes oil from the coffee, which brings us to our second point.
Turn Coffee Into Liquid Fuel
Like most plant seeds, the coffee bean contains a significant amount of oil, which can either be squeezed out or chemically extracted. It can then be converted into biodiesel, a liquid with similar properties to that of regular diesel.
