Deu na Economist:
RUNNING a diesel engine on a plant-based fuel is hardly a new idea. Indeed, one of the early demonstrations shown by Rudolph Diesel, the German engineer who invented the engines at the end of the 1800s, operated on pure peanut oil. Diesel fuel made from crude oil eventually won the day because it was easier to use and cheaper to produce. Now new forms of biodiesel are starting to change the picture again. And one of the latest sources comes from the remains of a drink enjoyed the world over: coffee.
Biodiesels are becoming increasingly popular. In America, Minnesota has decreed that all diesel sold in the state has to contain 2% biodiesel (much of it from the crops grown by the state’s soya farmers). Biodiesel can also be found blended into the fuel used by public and commercial vehicles and by trains in a number of countries. Aircraft-engine makers are also testing biofuel blends. Because biodiesels can be made from materials derived from plants, which use carbon dioxide to grow, they potentially have a much lower carbon footprint than petroleum-based fuels.
Coffee is also a plant product, but once the beans are ground and used they end up being thrown away or put on gardens as compost. Narasimharao Kondamudi, Susanta Mohapatra and Manoranjan Misra of the University of Nevada at Reno have found that coffee grounds can yield by weight 10-15% of biodiesel relatively easily. Moreover, when run in an engine the fuel does not have an offensive smell—just a whiff of coffee. Some biodiesels made from used cooking-oil leave a car exhaust smelling like a fast-food joint. And after the diesel has been extracted, the coffee grounds can still be used for compost.
The researchers’ work began two years ago when Dr Misra, a heavy coffee drinker, left a cup unfinished and the next day noticed that the coffee was covered by a film of oil. Since he was investigating biofuels, Dr Misra enlisted his colleagues to look at coffee’s potential. The nearby Starbucks was happy to oblige by supplying grounds.
Pois é. Bem antes de eu saber disso eu costumava brincar chamando às vezes o café de “combustível”. Mal eu sabia que o que era brincadeira viraria algo para valer.