Scientists who have tested isobutanol, a fuel alcohol made from corn, say it packs more energy and has other pluses over ethanol.
A biofuel that will be produced commercially in Minnesota is turning out to have major advantages over ethanol, especially for engines that can't burn that fuel at higher concentrations.
Scientists who have studied isobutanol, an alcohol fuel made from corn and soon to be manufactured in Luverne, Minn., say it can be easily blended with gasoline at up to 16 percent, packs more energy than ethanol and doesn't appear to damage the engines of older cars, boats and lawn equipment.
"Isobutanol is a good fuel, and a lot of engines can burn it without problems," said James Szybist, a researcher at Oak Ridge National Laboratory in Tennessee who has tested the fuel.
Most gasoline sold in the United States is 10 percent ethanol, or E10. Urged on by the ethanol industry, the federal government this month registered the first companies to sell E15, or 15 percent ethanol.
But E15 has struggled to gain widespread acceptance, partly because, unlike E10, it is not approved for engines in pre-2001 cars, and any motorcycles, boats, off-road vehicles, lawn mowers or other power equipment. Using E15 in these engines, even by mistake, could cause damage and void warranties.
The marine engine industry, which has reported boat engine damage from E15, says its continuing tests of isobutanol-gasoline blends have found no similar problems.
"This could be the fuel of the future," said John McKnight, director of environmental and safety compliance for the National Marine Manufacturers Association, a trade group for the recreational boating industry.
At Argonne National Laboratory in Illinois, researchers who tested motor vehicle engines in a lab concluded that isobutanol "may prove to be a more attractive alternative than ethanol due to fuel characteristics that closely resemble gasoline," according to paper presented at a 2009 industry conference.
Small engine manufacturers also saw no red flags with isobutanol in testing last year at Briggs & Stratton. "It shows great promise if they can bring it market in a meaningful way," said Kris Kiser, president and CEO of the Outdoor Power Equipment Institute, an industry trade group, who diplomatically added: "I am not here to bash ethanol."
Gevo, an Englewood, Colo.-based biofuels company, is spending $40 million to convert a Luverne ethanol plant into the nation's first commercial-scale corn-to-isobutanol plant. It is set to open in June.
Without really trying, the new biofuel has landed in the middle of the debate over adopting E15 as the nation's standard motor fuel.
"We typically don't pick winners and losers," said Thomas Wallner, a scientist at the Argonne lab whose findings about isobutanol have been mostly positive. "It is a very loaded topic."
Isobutanol's pluses are that it doesn't absorb water like ethanol, isn't known to cause corrosion, doesn't evaporate as easily and has more energy than ethanol though still has 17 percent less than gasoline, according to researchers. It mixes so well with gasoline that it can be sent through pipelines.
On the other hand, isobutanol has slightly lower octane, which means it needs to be blended with gasoline having a higher anti-knock rating. That alone represents an obstacle to getting the new biofuel to pumps.
Wendy Clark, a scientist at the National Renewable Energy Laboratory in Golden, Colo., said 90 percent of the gasoline sold in the United States is refined for mixing with ethanol. "It is not the right blendstock for butanol," said Clark, who is working with industry officials on specifications to address that issue.
Yet another problem, at least in Minnesota, is a state law that specifies only ethanol can be blended with gasoline. Gevo has been unsuccessful in getting legislators to change the law, which may mean the fuel will first be sold at gas stations in other states, most of which have no such mandate.
From the beginning, Gevo has said it hoped to sell isobutanol to chemical makers to make other products. For example, Gevo recently announced a deal with Coca-Cola Co. that would use isobutanol to create another chemical, paraxylene, for pop bottles derived from plant materials.
Gevo President and Chief Operating Officer Chris Ryan said the company also intends to sell isobutanol as fuel. The plant in Luverne will produce 18 million gallons of isobutanol annually.
With the boating industry showing interest, Ryan said the company made a deal with a marine fuels distributor to offer a gasoline-isobutanol blend at marinas. He said such sales are not barred by Minnesota's ethanol-preference law, which applies only to road vehicles.
One big challenge is whether Gevo's biofuel can compete against ethanol on price. Ryan said isobutanol likely will cost more to make than ethanol, but the gasoline needed to mix with it can be produced using less-expensive fractions o crude oil.
"What that means is that a fuel manufacturer would be able to make that base gasoline at a lower cost, blend butanol on top of it, which on a per-gallon basis would be a higher cost than ethanol, and sell their butanol-gasoline at the same price," Ryan said.
For motorists, and the ethanol industry, none of these changes will happen right away. Robert Wisner, a biofuels economist at Iowa State University, said it could take two or three years before it's clear whether more ethanol plants, like Luverne's, are better off converting to isobutanol.
"I don't see it as a threat to the industry, but simply a transition stage," Wisner said.
David Shaffer • 612-673-7090