Hay growers are used to hearing that cellulosic ethanol — biofuel made from grass, wood or other non-edible plant material — is just five years away, says USDA-ARS research geneticist Michael Casler. They've been hearing that same estimate year after year after year, he adds.
“We're all waiting for it. But there are still a lot of cold feet out there — a lot of uncertainties about how it is going to work,” says Casler, who works with switchgrass and other potential biomass crops at the U.S. Dairy Forage Research Center, Madison, WI.
No commercial-scale biorefineries yet exist that produce cellulosic ethanol from forages such as switchgrass — deemed by the U.S. Department of Energy (DOE) as a prime biomass crop that can provide good yields with low inputs on marginal land.
Pilot plants starting with crop residues like corn cobs and stover are scheduled to begin production this year. But there are some huge hurdles to jump. They include: 1) Finding a way to efficiently convert cellulosic plant materials to allow for fermentation into cellulosic ethanol; and 2) Passing government policies that will encourage biorefinery investments and growth as well as allow biomass crop production on Conservation Reserve Program (CRP) land.
Burt English believes a switchgrass biorefinery will be up and running by 2012 in Tennessee.
Last spring, says English, a University of Tennessee economist, 16 farmers in eastern Tennessee began raising more than 700 acres of switchgrass to supply a research-scale plant that should be running this coming December.
“We're in the process of trying to get another 2,000 acres planted this year. The fields have to be within 50 miles of Vonore, where the plant is going to be located,” he says.
That pilot facility, formed through the university, DuPont and its Denmark-based partner, Danisco, will have a 250,000-gallon/year capacity and is expected to produce cellulosic ethanol from corn residue by late 2009 and from switchgrass by 2010. DuPont-Danisco also plans to build a commercial-scale switchgrass refinery in the state within the next three years.
A 2007 government mandate that domestic renewable and alternative fuels production must increase to 36 billion gallons per year by 2022 — with 16 billion of those gallons as cellulosic — isn't the first attempt the government has made to find ways to provide fuel domestically. But the Renewable Fuel Standard, with $1.6 billion in energy funding, $210 million of which was targeted for cellulosic research, is the most progressive.
DOE further committed cost-share funds of $385 million toward the building of six biorefineries, to produce more than 130 million gallons of cellulosic ethanol per year by 2012.
In the recent Farm Bill, another $1 billion in funding was made available toward energy research and biorefinery establishment around the country.
The energy law and funding are all part of a scenario researchers have seen before: Oil supply gets tight as demand and fuel prices escalate. Then the government shells out money to find ways to produce fuel domestically.
Joe Bouton, director of the Noble Foundation, Ardmore, OK, started researching switchgrass right after the 1990s Second Gulf War. When fuel prices dropped and supply increased, switchgrass research funds dried up, he says.
Until a few years ago, Ken Vogel, USDA-ARS forage breeder at the University of Nebraska-Lincoln, must have felt like the Lone Ranger; few colleagues were also breeding switchgrass. “Now there are quite a few people getting involved,” Vogel says.
USDA and universities are growing test plots of other potential biomass crops as well, including giant miscanthus, sugar cane or energy cane, sorghum, sweet sorghum, alfalfa and perennial grasses such as bermudagrass, napiergrass and bahiagrass.
Although wood residues or products and corn residues will likely be the first cellulosic materials utilized in biorefineries — because they are more readily available — switchgrass continues to be thought of as a main player.
“Switchgrass has a lot of things going for it; it's got a seed that's easy to plant. It's easy for farmers to handle and, for the first generation of energy crops, we're furthest along on this and we've got the most information on it,” says Vogel.
This perennial warm-season grass can be planted with few inputs and give high yields for 10-15 years. Some of Vogel's switchgrass plots have yielded more than 10 tons/acre of the 6'- to 8'-tall crop. Farm fields, however, aren't expected to yield more than 6-8 tons/acre, and a University of Nebraska switchgrass cost-of-production study on 10 northern Great Plains farms brought yields averaging only 2-4 tons/acre over five years.
Yet switchgrass grows well on Coastal Plains' sandy soils, says Jim Frederick, agronomist at Clemson University's Pee Dee Research and Education Center at Florence, SC. He was pleased to get 6 tons/acre from two harvests of a second-year switchgrass stand. It takes three years for the crop to produce top yields, he adds.
The perennial also can be grown on marginal land. “There are almost 40 million acres of land in the CRP; that's the type of land that we think switchgrass can be utilized on,” Vogel says.
All the same, says Tennessee economist English, “we have to recognize that the yields will certainly be less on marginal land than they would be on good land.”
Using land that food crops can't be or aren't grown on reduces the “food vs. fuel” argument corn-ethanol critics use, says Casler.
“One of the nice things about CRP land is that perennial biofeedstocks can still continue to serve the soil and water conservation need,” he points out. “They can even benefit wildlife prior to harvest. And usually perennials are not harvested until the end of the year or sometimes even during the winter or after.”
Switchgrass researchers say the crop is ready.
“We have new varieties ready to go because of early work,” Bouton says. “It's just that there aren't a lot of bioprocessing plants taking switchgrass. Right now people are calling the Noble Foundation, asking, ‘Should I grow switchgrass?’ The first question we ask them is: ‘Do you have cows to feed it to?’ ”