WASHINGTON (Reuters) — Scientists have developed an efficient way to make ethanol without using crops.
They said their process turns carbon monoxide gas into liquid ethanol with the help of an electrode made of a form of copper.
The new technique may be more environmentally friendly and efficient than the current method, they added.
Critics say growing crops for biofuel is energy intensive, takes up vast tracts of nonagricultural land and uses too much water and fertilizer. They also say diverting corn and sugar to make biofuel 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 Renewable Fuels Association.
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 emphasize 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 usually produced at high-temperature fermentation facilities that chemically transform corn, sugar cane and other plants into liquid fuel.
Kanan and his colleagues built an electrochemical cell, which consists of two electrodes put in water and saturated with carbon monoxide gas. One of the electrodes was made of a material they call “oxide-derived copper.”
The scientists said the carbon monoxide gas was converted into ethanol when voltage was applied across the electrodes. They hope to take carbon dioxide from the atmosphere and convert it to carbon monoxide, which would then be fed into the copper-oxide catalyst.
The researchers hope the catalytic cell would be powered by a renewable energy source such as solar or wind.
Chemist Aaron Appel of the U.S. Department of Energy’s Pacific Northwest National Laboratory said the research demonstrates “a re-markable improvement in selectivity and energy efficiency” for the production of ethanol from carbon monoxide. Appel was not part of the study but wrote a commentary in Nature on the findings.
Advocates call ethanol a green energy source that, compared to gasoline, reduces greenhouse gas emissions that contribute to climate change.
The Renewable Fuels Association said ethanol directly supported more than 86,000 U.S. jobs in fuel production and agriculture in 2013.
Last November, the U.S. Environmental Protection Agency proposed cutting the amount of ethanol required to be mixed with the gasoline supply, responding to pressure from the petroleum industry.
It marked the first planned cut to the renewable fuel targets that were written into a 2007 U.S. law.