UT's Field of Dream Weeds


Partnering in the use of ORNL's Spallation Neutron Source and vaunted supercomputing capabilities have been heralded as the prime movers in lifting UT to a position of research eminence. But the biggest impact of any joint UT-ORNL research endeavor now underway just might be derived from a field of weeds.

Switchgrass is a scraggly looking plant that can grow as tall as 12 feet on just about any soil. It's also a source of cellulose that can be converted into ethanol and that, of course, means fuel. Under the aegis of their Joint Institute for Biological Sciences, UT and ORNL are already in the forefront of studying how to make this conversion process economically viable. Gov. Phil Bredesen's budget would provide $10 million for this research in the fiscal year ahead. And UT and ORNL are vying for a $125 million grant from the federal Department of Energy that's soon to be awarded for creation of a Bioenergy Research Center.

Bredesen's budget also includes funding for a $40 million pilot plant to be built at a site to be determined in the Knoxville area. Within two years, the first such switchgrass processing plant in the nation is expected to be producing five million gallons a year of what UT has trademarked as Grassoline.

Five million gallons is just a drop in the bucket in relation to the 150 billion gallons of gasoline consumed annually in the U.S. or even the three billion gallons consumed in Tennessee. But if the pilot operation goes as well as he expects, UT's Executive Vice President and Vice President for Research David Millhorn foresees Tennessee's Grassoline production growing over the next decade to a billion gallons a year at some 10 plants scattered around the state. Beyond that, he foresees switchgrass and related biomass yielding half or more of the 35 billion gallons of ethanol that the Bush administration has set as a national goal by 2017.

â“We think Tennessee has a chance to be the national leader in this field, and if we lead, we can have intellectual property and licensing income over and above the revenue to growers,â” Millhorn says. He places the latter on the order of $500 million for the 10 million tons of switchgrass it would take to produce a billion gallons of ethanol. And he believes that most of that would represent a boost to the state's existing agricultural economy because the switchgrass would mainly be grown on what's presently pastureland without displacing cash crops. Beyond that, he foresees the economy of the state's rural areas benefiting from the processing plants, both because at least some of them could be grower-owned co-ops and because all of them would have to be located close to growing areas due to the high cost of transporting the bulky switchgrass.

All of these rosy prospects are contingent on scientific, engineering and logistical solutions to a host of challenges. â“There's a list of research questions about a mile long, but I think the goals are reasonable and we expect to meet them within a five-year time frame,â” says Kelly Tiller, a UT professor of agricultural economics who has been in the forefront of the university's efforts. She divides the research needs into two broad areas:

1. Genetically engineering switchgrass plants to increase their cellulose content and their yield per acre. A mature stand of switchgrass, which is a perennial plant with a deep root system, presently yields about six tons per acre, and the goal is to double that over time. Bredesen's budget also includes $8 million to induce growers to plant upwards of 10,000 acres in the Knoxville area needed just to support the pilot plant.

2. Biochemically increasing the amount of ethanol derived from a ton of switchgrass to 100 gallons or more from around 60 presently, primarily by improving enzymes for breaking down its cellulose. Deriving other valuable chemicals as byproducts of the refining process is another key to the economic equation just as petrochemicals loom large in the oil-refining process and thus the price of gasoline.

At present, nearly all of the 7.5 billion gallons of ethanol produced in this country is derived from corn. That output is expected to grow as farmers devote more acreage to corn and the percentage of the crop going into ethanol continues to increase. This year, corn acreage is expected to increase by 10 percent to 88 million acres, yielding a projected record corn crop of 12.2 billion bushels. Of that, an estimated 3.2 billion bushels is expected to go into ethanol, up from 2.2 billion last year.

But further growth is limited both by suitable acreage constraints and by the upward pressure that demand for ethanol is placing on the price of corn, which has doubled to $4 a bushel over the past two years. Higher corn prices, in turn, put upward pressure on the price of meat because corn feed is a big part of the cost of poultry, beef and pork production. Moreover, barring a further surge in oil prices, even the 51-cent-a-gallon subsidy in the form of tax credits that corn-based ethanol processors now receive won't be enough to cover their costs if the price of corn goes higher.

The two desiderata driving the quest for increased use of ethanol, as a matter of national policy, are 1) reducing dependence on imported oil, and 2) curbing emissions of carbon dioxide and other greenhouse gases that are believed to be a cause of global warming.

Nearly 60 percent of the oil consumed in the United States is imported, and that percentage stands to keep going up unless oil is replaced by alternative fuels. Ethanol is the single most promising alternative, assuming automobile makers equip their cars with engines that can run on 85 percent ethanol (E85) that is now prevalent in Brazil (where the fuel is derived from sugarcane).

In sharp contrast with fossil fuels, cellulose-based fuels are heralded as adding virtually nothing to carbon dioxide in the atmosphere. That's because plants like switchgrass consume as much CO 2 while growing as the ethanol derived from them emits when burned.

For all these benefits to be realized, the challenge facing UT-ORNL researchers is to make large-scale conversion of switchgrass into ethanol commercially viable. Their success would be a boon not only to Tennessee's economy but also the nation's and the world's well-being.

â" Joe Sullivan


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