Farmers in a 10-county area surrounding Vonore, TN, grew 2,613 acres of switchgrass for biofuel production and research development this past year — for $450/acre/year on three-year contracts. By the end of 2010, about 7,000 acres of switchgrass are planned to be in production.
Those farmers and this perennial grass, deemed a high-priority crop in the search for alternative fuels, are an integral part of a $70.5 million state-funded project organized by the University of Tennessee (UT), better known as the Tennessee Biofuels Initiative. The Initiative is a farm-to-fuel business plan developed by UT Institute of Agriculture researchers.
“It's a very comprehensive program that is designed to demonstrate all the way from farm field production to cellulosic ethanol production,” says Kelly Tiller, director of operations for UT's bio-energy programs and president of Genera Energy, LLC.
Genera Energy, owned by the UT Research Foundation, partnered with DuPont Danisco Cellulosic Ethanol to build the pilot-scale biorefinery and research and development facility for cellulosic ethanol that, at presstime, was scheduled to open last month.
The pilot plant has the capacity to produce 250,000 gallons of cellulosic ethanol per year. That makes it large enough to give researchers data on what's needed for a commercial-scale cellulosic facility, Tiller says. A commercial biorefinery, producing 15-25 million gallons of biofuel a year, is on the drawing board to be functional in the next three to four years, she adds.
“We're focused, too, not just on ethanol production, but also on other uses of switchgrass, pelleting it so that it can be co-fired with coal, for example.” The researchers are also looking at switchgrass' gasification potential as well as other uses for switchgrass material that doesn't go directly into the biorefinery.
Researchers are also studying how to best manage the crop, Tiller says.
“Early in the season, it actually has quite a lot of protein. So we've done studies looking at grazing cattle on switchgrass for a period of time, then pulling the cattle off, allowing the biomass to grow out and harvesting it as a biomass crop at the end of the year. There are probably 40 different individual projects like that we could talk about.”
Those types of experiments, especially those tinkering with yield, were part of the consideration of how and why Tiller and her colleagues arrived at the $450/year-for-three-years contract.
“Price discovery is really difficult because it's just a very immature market — if there's even a market for switchgrass,” she says. “We had to find ways to arrive at a price attractive enough for farmers to be willing to participate and take on any risks. We don't want the price so high it sends the wrong market signals or provides any kind of long-term consequence.”
Paying only based on tonnage or other volume amount wasn't going to make farmers happy or willing when researchers wanted to experiment on production practices affecting yield, Tiller says.
“There were a lot of really practical questions about how could we even arrive at a fair yield-based payment. So, by doing it this way, it allowed us to gather several years worth of data” and try different management methods.
Forty farms are growing switchgrass for the pilot plant and research efforts on acreages ranging from 20 to 150.
“We really designed the switchgrass program as a very large-scale research experiment. The farmers involved represent a huge cross-section of sizes and of previous experience in managing crops and even farming, to some extent.” The grass is being grown on a wide range of soils and rotated in after various types of crops.
In 2008, 16 farmers planted 723 acres of the grass; an additional 1,910 acres were added in 2009 with an average establishment success rate of more than 90%. Average yield of 2008-planted crop was 5.2 tons/acre at about 18% moisture last year, says Ken Goddard, the UT Extension biofuel specialist who worked with contracted farmers.
Yields of 2009-planted switchgrass averaged from zero (15%) to 4 tons/acre because of grass infestations, he adds. Those fields “will have good stands of switchgrass this year. Mechanical weed control was needed to reduce shading from crabgrass, goosegrass, johnsongrass and yellow and giant foxtail. Those same fields will be harvested in year two and a yield of five tons per acre is expected.
“We're also doing some experimentation with alternative harvesting systems: an in-field chopping system and bulk-handling,” Tiller says. “This, again, is part of the research and trying to optimize harvesting, handling and shipping.”
The grass is harvested in a wide variety of packages — different-sized round bales to large squares. Standard-size packages will probably be required for efficiency by the time commercial biorefineries come on line, she says.
The first year's harvest was kept at a central storage site. This past year, some farmers were contracted to store some of the product.
“The sheer volume required to operate these facilities is tremendous, and the fact is, you don't have year-round harvest. You need to be able to feed a facility 24/7, so that's going to be something we're addressing going forward — how to handle the storage and the logistics,” Tiller says.
This year, in addition to the 6,000 acres of switchgrass needed for the pilot plant and research, the Biofuels Initiative was awarded a U.S. Department of Energy grant to grow another 1,000 acres. Its purpose: to compare the standard Alamo switchgrass variety with two improved varieties developed by Ceres, a biotechnology company. At least 800 acres will be grown to EG 1101, an improved Alamo variety; the rest will be seeded with EG 1102 Kanlow variety. Ceres sells its varieties under the Blade Energy Crops brand.