Biodiesel: A New Way of Turning Plants into Fuel

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"Once you break down all the sugars in the plant material, the only option we had before was to make ethanol," Wyman says. "This presents more options."

In the future, a single manufacturing center, after refining the biomass into sugars, could make biodiesel or ethanol, depending on market demand. However, Wyman also points out that the economic battle hasn't necessarily been won.

"In the end it's the price at the gas station where these technologies win or lose, not in the laboratory," he says.

To insure that both biodiesel and ethanol become more competitive in the marketplace, Wyman says that a key breakthrough is needed to make diesel fuel or other products such as ethanol competitively from sugars. According to him, advances in this area could beat wholesale gasoline prices.

And some believe that breakthrough is on the horizon. Advancements in the last two years in enzyme technology by the National Renewable Energy Laboratories and private companies such as Iogen and Novozymes have substantially reduced the costs of cellulose transformation, which is tantalizingly close to making the whole system economically competitive with cheap gas.

The new process being developed by James Dumesic, professor of chemical and biological engineering at the University of Wisconsin, and Huber will help to reduce those costs by limiting the amount of waste, since any type of plant matter can be fed into their system. Unlike current ethanol refineries, which can work only with high-glucose content materials such as corn, the biodiesel fuel generated by this process uses the cellulose, roots, and stems of any plant.

That means the waste biomass of America's vast agriculture industry -- everything from corn stover (the stems and leaves of the plant) to peanut shells and fallen leaves -- can be used. A recent U.S. Department of Agriculture study (see Notebook) estimated that more than 1.3 billion tons of such waste is produced every year. If all of it were turned into biodiesel, it would provide enough fuel to replace one-third of the petroleum consumed in the United States. Furthermore, turning currently unused farmland into grassland to be harvested for biodiesel production would easily account for the other two-thirds of petroleum needs.

That, of course, means another beneficiary of such a transformation would be family farmers, according to Pacific Ethanol's Jones. Ethanol refineries owned by cooperatives of farmers already supply the bulk of U.S. ethanol production, and biodiesel refineries could be modeled on the same program.

Honing this new process, though, is only the first step in the very long process of transforming the country to a biodiesel nation. For that to happen, the entire U.S. commercial car fleet would have to switch from internal combustion engines to diesel ones, of course; but the move might be attractive, since the new engines would cause less pollution (biodiesel vehicles would produce far fewer pollutants like sulfur and nitrogen oxides.)

Such a sea-change in the U.S. transportation infrastructure won't happen quickly. More likely, biodiesel production will start slowly, then ramp up to an industrial scale, if it's competitive with diesel and gasoline.

Still, Huber thinks that his team has taken a major step toward harnessing one of the world's most-prevalent, yet least-utilized energy resources.

"If this is a success," he says, "I can say that I helped to convert our biomass resources to fuel our transportation system."