October 22, 2007

Tennessee Bets $70 Million of Taxpayers' Money on Risky Switchgrass Gas Scheme

Conservationists consider it wildlife habitat and farmers have long thought of it as a weed, but if a new pilot cellulosic ethanol plant being built in Tennessee proves successful, "it" could soon be the source of fuel to replace up to 30 percent of the gasoline now used in the state.

"It" is switchgrass, and this past year Tennessee Gov. Phil Bredesen convinced the state legislature to bet $70 million of taxpayers' money on a plan to make Tennessee a leader in the production of ethanol fuel from switchgrass.

A $40.7-million research-scale biorefinery is being constructed in an industrial park in the town of Vonore by the University of Tennessee, funded by $70 million in state tax dollars. UT has partnered with Mascoma Corporation of Cambridge, Mass., a pioneer in cellulosic biofuel production, to build and operate the plant.

Once it starts operating the East Tennessee biorefinery will produce cellulosic ethanol from switchgrass, a hardy, perennial, warm-season forage crop that grows in large volume, requires few inputs, and has a high cellulosic content. One acre of switchgrass can produce 500 gallons of ethanol. Corn? Not so much - the heavily hyped and federally subsidized production of ethanol from corn nets far less ethanol per acre.

The Tennessee Cooperator, magazine of the Tennessee Farmers Cooperator reports on the project:

Because it does not compete with food or feed uses, using dedicated energy crops like switchgrass to produce cellulosic biofuels may be the answer to producing affordable, domestic, renewable fuel without raising food or feed costs, said Kelly Tiller, director of operations for UT's bio-energy programs, speaking to some 150 farmers and community members who turned out for a public forum on biofuels in late August at Walters State Community College in Morristown.

"We really feel that cellulosic-based fuels are the next wave of the future and have long-term sustainable potential," said Tiller. "We think that within a 20-year period, we could be producing and consuming about 1 billion gallons of cellulosic biofuels in the state of Tennessee. That would displace our current use of gasoline by about 30 percent."

According to Wikipedia's entry on switchgrass, the grass "has the potential to produce the biomass required for production of up to 100 gallons (380 liters) of ethanol per metric ton [which] gives switchgrass the potential to produce 1000 gallons of ethanol per acre, compared to 665 gallons for sugarcane and 400 gallons for corn."Sounds good so far, right?

However, there is debate on the viability of switchgrass, and all other biofuels, as an efficient energy source. University of California, Berkeley professor Tad Patzek argues that switchgrass has a negative ethanol fuel energy balance, requiring 45 percent more fossil energy than the fuel produced. On the other side, David Bransby, professor of energy crops at Auburn University, has found that for every unit of energy input, switchgrass yields four units out. In a 2007 lecture Professor Richard Muller, also of the University of California, Berkeley, noted that it is the conversion of switchgrass biomass into ethanol which introduces significant inefficiencies.

Cross-posted from Ecotality Life. (Pictured: University of Tennessee Extension agent Ken Goddard in a field of switchgrass. Photo from the Tennessee Cooperator.)

Update: In the comments, Martin Kennedy mentions a recent National Geographic story on the fuel potential of algae. Here's a link to an info-graphic on that magazine's website comparing various biofuels. And here's a link to the story.