Scientists say they have developed a new way to make liquid ethanol efficiently without using corn or other crops needed in the conventional method for producing the biofuel.
The new process turns carbon monoxide gas into liquid ethanol with the help of an electrode made of a form of copper. Those developing the technique said it may be more environmentally friendly and efficient than the current method.
Critics of biofuels say growing crops for them is energy-intensive and takes up nonagricultural land, using too much water and fertiliser. They also say diverting corn and sugar to make biofuels pushes up food prices.
The United States leads the world in ethanol production, with 13.3 billion gallons in 2013, followed by Brazil's 6.3 billion gallons, according to the Washington-based Renewable Fuels Association, which represents the US ethanol industry.
A group of scientists led by Stanford University chemist Matthew Kanan described the new method in research published in the journal Nature. Kanan said a prototype device could be ready in two to three years, enabling an assessment on whether the process can become commercially viable.
"I emphasise that these are just laboratory experiments today. We haven't built a device," Kanan said. "But it demonstrates the feasibility of using electricity that you could get from a renewable energy source to power fuel synthesis — in this case ethanol. There are some real advantages to doing that relative to using biomass to produce ethanol."
Ethanol fuel is generally produced at high-temperature fermentation facilities that chemically transform corn, sugarcane and other plants into liquid fuel.