The long-term growth of the U.S. sorghum industry lies in part with scientists unraveling paths to economically produce cellulosic ethanol.
“We are very excited about the future of energy (forage — whole plant) sorghum as the cellulosic ethanol industry becomes more of a reality in future years,” according to Tim Lust, chief executive officer, National Sorghum Producers (NSP), Lubbock, Texas.
“Sorghum is very unique; it’s the only crop that has grain, sugar, and cellulosic types,” Lust said. “Grain sorghum is today’s world. Sugar and cellulosic is where we see the future.”
About 30 percent of the U.S. grain sorghum crop is utilized to make grain ethanol. Pinal Energy near Maricopa, Ariz. is among the many U.S. ethanol plants creating fuel from sorghum. Forage sorghum is an important ingredient in livestock and pet feeds.
Ten percent of the U.S. grain sorghum crop is sold through U.S.-sponsored food aid programs. Sorghum is a gluten-free crop important for people with a gluten allergy.
For future cellulosic ethanol production, Lust says energy sorghum per acre out yields switchgrass and miscanthus, and uses less water than comparable feedstocks.
“Sorghum has advantages as a low-water, low-input crop that leaves a very friendly carbon footprint that will be very important for the future of our industry,” Lust said.
Tomorrow’s grain-based ethanol industry will not be your father’s ethanol. Researcher John Ashworth says energy sorghum growers in the future may sell the crop directly to a local biorefinery.
In Georgia, a biorefinery’s main feedstock could be wood; in other states sorghum and corn silages could be the major ingredient.
Ashworth is the partnership development team leader with the National Bioenergy Center at the National Renewable Energy Laboratory (NREL) in Golden, Colo. The NREL team is researching how to economically produce cellulosic ethanol from woody plants.
“We are beginning to look for ways to scale up cellulosic ethanol technology including which feedstocks to use and how to convert them,” Ashworth says. “Another objective is to determine if gasoline and diesel fuel can be made directly from crops including forage sorghum. The answer is probably yes.”
The U.S. government wants 36 billion gallons of fuel generated from biomass by 2022. Grain ethanol production is currently about 10.7 billion gallons. Ashworth predicts grain ethanol production will level out at about 15 billion gallons over the next few years.
To achieve the government goal, other low-cost feedstocks will be required to generate the remaining 21 billion gallons of alternative fuels.
The NREL is developing a biorefinery process that tests a biochemical effort to derive usable products from biomass. The process includes a chemical, pressure, elevated temperature, and steam pre-treatment of the biomass; followed by an enzymatic hydrolysis step to break down the feedstock to simple sugars, plus fermentation, product separation, and recovery.
The NREL, a U.S. Department of Energy laboratory, wants to develop workable, cost-effective biorefinery concepts, and turn them over to private companies to invest the needed capital to perfect and scale up the process.
A real-time biorefinery would make a variety of products, Ashworth says, ranging from lower-value products including ethanol, butanol, or diesel fuel; plus higher-valued materials including adhesives and phenols to help offset the capital investment.
“The whole point is the refinery would make many products. It’s all about making a biorefinery economical,” Ashworth said.
Creating cellulosic ethanol from forage sorghum and sudangrass is more difficult than breaking down the simple sugars in grain. Sudangrass and sorghum have long, complex chains of sugars and glucose encircled by tough lignin. The issue becomes how to economically convert the substances into cellulosic ethanol.
NREL experimental processes initially produced cellulosic ethanol for about $6 a gallon in 2001, an uncompetitive amount given the price of oil. Cheaper and more effective enzymes, plus pilot plant efficiencies, reduced the amount to $2.36 in 2009.
“We need to reach $1.50 a gallon to make the economics competitive with gasoline,” Ashworth said. “We are on the way.”
Ashworth is convinced that traditional grain and cellulosic ethanol production could triple or quadruple by the year 2022.
“I think forage sorghum definitely has a future in cellulosic ethanol development,” Ashworth said.
Sorghum’s future success also depends on increased yields for all sorghum types, says NSP board chairman Gerald Simonsen, a Ruskin, Neb. grower.
Growers in Kansas, the nation’s largest sorghum-producing state, achieved an all-time record state yield average of 88 bushels per acre in 2009, up from 78 bushels in 2008.
“That is a huge increase, but it’s still not where we want it to be,” Simonsen said.
Average U.S. sorghum yields increased 5.4 bushels to 69.4 bushels per acre from 2008 to 2009. Sorghum was planted on about 7.7 million acres in 2007.
Also aiding sorghum’s future are the NSP’s successful lobbying gains, including a higher sorghum crop insurance price election from the Risk Management Agency; from 88 percent in 2009 to 97.8 percent in 2010.
“This is by far one of the best things that could have happened for U.S. sorghum producers last year,” Simonsen said. “This will greatly help sorghum producers better manage their risks. On my farm the change means a $35 per acre difference in my bottom line.”
Another major industry victory is sorghum qualified as an advanced biofuel feedstock under the Energy Independence and Security Act of 2008.
“This provides some incentives for ethanol plants and producers using sorghum as a feedstock,” Simonsen said.
Other advances for the sorghum industry are benefits gained through the grower-funded United Sorghum Checkoff program started in May 2008. About $7 million was collected in 2009.
Among the projects include market development and an Internet database to help people search for sorghum information online. Other activities include research on over-the-top grass control in sorghum fields, and a sorghum distiller’s inclusion calculator to assist in marketing sorghum distiller’s grain.
Sorghum is grown in 21 states.