By Bill Dockery

“Eat local” is the trendy admonition from a new generation of environmentally aware consumers who tout the ecological and economic benefits of buying food produced close to home.

“Fuel local” may become the next catchy slogan as the University of Tennessee’s new biofuels program turns wild grasses into ethanol to power automobiles and other machines traditionally powered by gasoline engines.

The Tennessee Biofuels Initiative promises to create—from scratch—a major new industry that will reduce the nation’s dependence on foreign oil and provide farmers in the state with a significant new cash crop.

“We expect that this technology can eventually produce a billion gallons of ethanol a year,” says David Millhorn, UT executive vice-president. “If you are making a billion gallons of fuel, that’s like finding an oilfield in Tennessee that never goes dry.”

Priming the [Fuel] Pump

The Tennessee legislature provided $40 million to the university in 2007 to create the Tennessee Biofuels Initiative, an ambitious research and development project that will focus on extracting fuel-grade ethanol from the cellulose in woody grasses and trees. The university has partnered with Mascoma Corp., a Massachusetts-based firm that specializes in research on enzymes and organisms that break down the cellulose in woody materials. Mascoma will bring its own sources of capital into construction of the pilot plant, which will be located in the Niles Ferry Industrial Park in Vonore, Monroe County. Additional state funds will provide $8 million to farmers who will grow the initial switchgrass feed stock, as well as research and development monies that will allow the university and ORNL to leverage other research opportunities. The total state investment is expected to exceed $70 million.

Meanwhile, the U.S. Department of Energy has announced that nearby Oak Ridge National Laboratory would receive $125 million for a national bioenergy research center that will explore new ways to produce fuel from biomass. UT and Mascoma are also partners in that effort, which involves a number of universities, foundations, private corporations, and individuals.

A Sturdy Crop

Switchgrass is the primary source of biomass that UT specialists will use in initial research and development, though poplar trees and wood chips are another possible fuel source. The grass is a good fit with Tennessee farming, says Kelly Tiller, the UT agricultural economist who is a codirector of the initiative.

“Switchgrass grows well on fairly marginal land, and it requires little chemical fertilizers or herbicides and little management,” Tiller says. “It’s very much like a hay crop. It’s beneficial to conservation and wildlife management, it stabilizes the soil, and it doesn’t require a lot of special equipment to grow or harvest.”

The grass, a remnant of the tall-grass prairies that once covered the center of the continent, is a perennial that does well in drought and hot temperatures and will require replanting only every decade or so. Millhorn says the UT Institute of Agriculture has been working closely with the state’s farming community to get acreage planted in the grass.

“You have to start with the farmer. You have to have a producer of biomass showing the farmers how they can make money growing switchgrass,” Millhorn says. “We’re working closely with the Tennessee Farm Bureau to get a head start on producing the grass we’ll need for the pilot program.

“The pilot plant is a research facility, but we estimate it will use 170 tons of grass a day to produce 5 million gallons of ethanol a year—that amounts to a need for about 8,000 acres of crop.”

Tennessee is a great state for this endeavor, Millhorn says, because the state has a long growing season and adequate rainfall. The growing season ranges from mid-April and May through early November. He does not expect switchgrass cropping to have an adverse affect on the acreage farmers allot to food crops or cotton.

An Integrated System

Tiller, an agricultural policy specialist who started her academic career as an undergraduate at UT Chattanooga, sees the Biofuels Initiative itself as a giant research project. She points out that, while the corn ethanol industry is the product of more than a century of economic and agricultural practices, UT’s development of a vertically integrated cellulosic ethanol industry will happen all at once.

“One of the things that makes this project stand out is that we will have the entire system integrated,” says Tiller. “UT’s initiative will have to have a whole-system approach, from production on the farm to manufacture at regional centers to local distribution.”

Distribution is one of the key issues that will make grassoline production and usage a local endeavor. Traditional petroleum-based products—crude oil, gasoline, diesel oil—can be sent through long transcontinental pipelines as slugs of liquid because they do not mix quickly with each other. On the other hand, ethanol is readily soluble with petroleum products and even with water, as anyone who has ever mixed bourbon and branch water knows. “Grassoline” cannot be piped; it must be trucked to its destination. Thus UT agronomists see most of the grassoline being used in regional markets within the state.

The Biofuels Initiative’s research agenda will also include finding uses for lignin, the woody part of the cell walls of green plants, including switchgrass and poplar trees. Tim Rials, who is the other codirector of the Tennessee Biofuels Initiative, says that in the early stages of the project the lignin will be burned to fuel the ethanol-making process. But he expects further research at UT and ORNL to find ways to turn the material into a precursor to carbon fiber, a potentially high-value product.

The proximity of the biofuel plant to Oak Ridge and Knoxville is important to the project, especially as new products and processes are researched and developed.

“What you’ll see is a hand-in-glove fit,” said Rials, who also directs the Southeastern SunGrant Center for the U.S. departments of agriculture, transportation, and energy.

“UT and ORNL researchers will team up on both discovery work and fundamental research. The nearby pilot plant will be available for evaluating products—enzyme systems, feed stocks, and so forth. It will be a unique capability.”

Tags: Biofuel • Biology • Computing • Energy • Engineering • Environment • ORNL • Technology