Curiosities: What will be the most likely fuel to replace gasoline?

“What are the major benefits of using cellulosic ethanol to fuel our cars? We reduce spending on importing energy, have the potential to do this with less harm to our environment, and have the ability to turn agricultural or other waste products into fuel.”

Tim Donohue

Today, ethanol is a fuel additive used to replace or decrease the need for fossil fuels in trucks, automobiles and other engines. Most of this ethanol comes from the sugars within corn kernels, but the search for other sources of sugar is under way.

“The likely candidate? Ethanol made from sugars in cellulose, or ‘grassoline,’ as one of my fellow researchers likes to call it,” says Tim Donohue, a professor of bacteriology at UW–Madison and the director of the Great Lakes Bioenergy Research Center.

Cellulose is an abundant form of plant biomass that cannot be easily broken down into sugars. As a consequence, very little of the plant cellulose is used today to generate fuel.

“Society has thousands of years experience in making ethanol for beer and wine,” says Donohue. “Once we crack the cellulose code and release the sugars from cellulose fibers, we can begin to generate ethanol and other fuels from cellulosic biomass.”

Time and technology developments will tell whether tomorrow’s cars run on gasoline mixtures of 20-30 percent ethanol or the so-called E85 fuels (which contain 85 percent ethanol).

“What are the major benefits of using cellulosic ethanol to fuel our cars?” asks Donohue. “We reduce spending on importing energy, have the potential to do this with less harm to our environment, and have the ability to turn agricultural or other waste products into fuel.”