August 03, 2016

Crop waste products could power biofuels

by Andrea Hahn

CARBONDALE, Ill. -- What crop farmers leave behind in the field – wheat straw and corn stover – could be a key factor in the next stage of biofuels. 

When most people talk about biofuel, they mean corn-based ethanol -- the kind that’s in gasoline pumps all across the country. Corn, and also soybeans, produce first-generation biofuels. The term refers to the fact that corn ethanol was the first biofuel to gain widespread acceptance and use. It also refers to the nature of the biomass -- the organic material being used. Corn and soybeans, and in some areas sugar cane, were already under mass production for food; the biofuel was an additional use. 

Ira Altman, professor and chair of the Department of Agribusiness Economics at Southern Illinois University Carbondale, is interested in second-generation biomass -- specifically in wheat straw and corn stover, what’s left behind after harvest. 

He grew up on a farm in Saskatchewan, Canada, where his family grew grains and raised beef cattle. When he went away to the University of Saskatchewan, he majored in economics and political science, then decided to stick around for a master’s degree in agricultural economics. The first-generation biofuel movement was in full swing. It was doing so well, Altman, with his interest in developing industries, didn’t find much there to interest him. 

But the second-generation biomass product, now that was interesting. 

“Early studies showed second-generation biomass was competitive with first-generation biomass,” Altman said. “So why didn’t it take off? I believe it’s because corn is a mature industry. There is a well-developed supply chain. A company that wants corn to produce biofuel contacts ADM or some other large supplier and they have corn delivered.” 

That supply chain doesn’t exist for wheat straw and corn stover, each considered a waste product. Sure, farmers use it: straw is good for animal bedding and landscaping, stover is often used for forage or fodder. But there isn’t a supply chain for it. 

Altman studied what was happening in western Canada with Iogen Corp., a pioneer in cellulosic biofuel production. Cellulosic ethanol is a biofuel made from second-generation biomass, including wheat straw and corn stover -- namely, organic material left behind during harvest of other organic material. 

“I can remember running down wheat stubble on our farm, going round and round, and when I learned about second-generation biomass I thought, ‘Man, wouldn’t it be great if my dad could make some money off this straw?’” 

Solutions that sound simple rarely are. Altman began studying the way companies like Iogen interacted with farmers to establish a supply chain. There are several ways to go about setting up a reliable supply of biomass. Iogen used a contract system in which farmers agreed to supply the biomass and to adhere to certain quality and storage guidelines. Altman surveyed the farmers for their reaction and their willingness to participate in this new venture. He found that farmers were agreeable as long as the price was right. Surveys he has conducted since in Missouri and Southern Illinois indicate the same. 

“Straw and stover are considered waste products but that doesn’t mean they don’t have value,” he said. “They are forage for cattle, and they contribute to soil fertility. So there’s a trade-off there.” 

Studies of the soil fertility issue, Altman said, indicate that farmers could take half the material every year, or clear the field every other year, and see no negative impact to their soil. Still, the price must be right to make the extra work worth it. Cellulosic biofuel producers need to keep their costs down as they grow from pilot to demonstration to commercial production, so naturally there’s contract negotiation. 

Cellulosic biofuel production in the United States is growing, albeit somewhat slowly. The Office of Energy Efficiency and Renewable Energy, part of the U.S. Department of Energy, offers grants to facilities to help them grow from demonstration to commercial. 

One advantage to second-generation biomass is that it stands outside the food versus fuel debate, though Altman doesn’t see that debate as one in crisis mode. “Right now we have and have had a surplus of corn,” he said. 

Altman noted that, while second-generation biomass is typically for liquid fuel, there are some indicators it might be useful in conjunction with coal for biopower. 

“The economy will drive it,” he said. “Right now fossil fuels are cheap. But that doesn’t mean we stop researching biofuels.”