SIOUX FALLS, S.D. — Ethanol might reign as the king of biofuels, but several companies are betting that a close cousin may overcome some of its shortcomings.
Butanol has traditionally been used as a paint thinner, cleaner and adhesive, but as a fuel additive it contains more energy than ethanol and could be blended into existing cars at higher percentages.
And unlike ethanol, butanol does not eat away at pipes, so it doesn’t need to be shipped by truck. That could help the nation meet its aggressive renewable-fuels standard of 36 billion gallons of biofuels to be blended into gasoline by 2022, said Andy Aden, a research engineer at the National Renewable Energy Laboratory in Golden.
“Our existing infrastructure has too many bottlenecks, and it’s just not going to cut it,” Aden said.
Chemical maker DuPont and oil giant BP are working on a pilot plant in the United Kingdom that will produce butanol from feedstocks such as wheat, corn, barley and rye. The two companies have also teamed with British Sugar to develop a commercial-scale ethanol plant that eventually would be converted to produce butanol once the process is perfected.
Aden said butanol as a fuel holds promise but that the technology is still in a low level of development.
“Despite what companies are saying, it’s still a fair ways off,” he said.
Gevo Inc., a Douglas County-based company backed by venture capitalists Richard Branson and Vinod Khosla, a co-founder of Sun Microsystems, said it’s solving that problem with a form of E. coli bacteria.
Butanol producers to date have used Clostridium acetobutylicum bacteria to munch on a variety of sugary feedstocks to produce acetone, butanol and ethanol.
By substituting an E. coli derivative developed by scientists at the University of California at Los Angeles, Gevo is able to produce only isobutanol, said Pat Gruber, the company’s chief executive.
The bacteria can be fed corn, sugar cane or cellulosic plant waste.
Gevo’s business model is to take existing ethanol plants and retrofit them into butanol plants, a transformation Gruber estimates would cost between 25 cents and 30 cents per gallon in capital.
“All we’re doing is changing the bug, adding some skids of equipment. Voila. It is now a butanol plant,” he said.
