From Sci-fi to Reality

Cellulosic Ethanol Plant Real to Farmers

Todd Neeley
By  Todd Neeley , DTN Staff Reporter
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As production of ethanol from corn residue increases, more fields are being stripped of corn stubble after harvest of the primary crop. (DTN/Progressive Farmer photo by Jim Patrico)

OMAHA (DTN) -- Five years ago when Nevada, Iowa, farmer Brian Sampson first heard about harvesting corn stover for ethanol, he thought it sounded akin to putting a man on Mars.

The corn, soybean and cattle producer now knows it's no longer in the realm of science fiction. Cellulosic ethanol production is ramping up right in his own backyard.

Sampson, who allows DuPont to harvest stover from about 660 of his 1,500 acres says he may one day allow DuPont to harvest stover from his whole farm.

"When I heard about stover back in the corn ethanol boom, it sounded like working on Mars," he said. "It was intriguing to me, and they are going to pay you money. We have been removing stover for cattle for a long time. They (DuPont) do a better, more uniform job of removing stover."

Sampson said with new, more-productive corn hybrids, there is an increasing need for better residue management.

When DuPont approached him with the idea of providing stover to the plant that officially launched commercial production Nov. 6, Sampson said he didn't immediately agree to it. He wanted to make sure demand for his stover would be something he could rely on and harvest would benefit his soils.

"I've been around the DuPont people more, and I think they have thought about and addressed the problems," Sampson said. "We're always going to hear the negatives. They're always going to be louder than the positives. Sometimes the negatives are, 'Are we going to have our soil?' I hate to sound cold, but what good is our soil if we don't use it?"


DuPont is banking on current producers to expand their feedstock involvement to meet the demands to double the number of farms involved for the plant to reach its full production capacity of about 30 million gallons.

John Pieper, stover feedstock work stream leader for DuPont, said about 200 producers provide feedstock within a 35-mile radius of the plant. DuPont needs about 500 producers and 200,000 total acres on board -- or about 400 acres per farm -- to provide the plant's expanding stover demand.

DuPont officials declined to provide information on what they pay farmers for stover.

Market prices for harvested corn stover are not reported on a regular basis, according to a June 2015 analysis by Iowa State University,….

However, ISU said large round stover bales have sold at auction for between $30 and $40 per bale. Some sales have been reported as high as $45. What DuPont pays for stover may vary, as the company harvests and produces square bales.

"Processers who wish to utilize corn stover for producing biofuels or other products generally will pay a higher price in order to assure they receive clean, dry material in timely fashion," ISU said in the analysis. "Rates are usually set in advance by contract."

ISU said producers who decide to sell unharvested stover to someone like DuPont could expect to see a cost associated with the loss of nutrients in the stover. In the analysis, ISU estimates the feed value of stover at around $43 per bale. Once harvesting and transportation costs are included, ISU estimates the bales are worth about $19 to the buyer.

For producers, the only added cost in this scenario, according to ISU, would be the nutrient value -- or about $4.92 per bale.

Since DuPont started the stover harvest, Pieper said, the company has seen individual producers decide to harvest their own stover.

"We started with control of the entire process," he said. "We bring in the equipment and personnel to do the harvest. We wanted to understand the harvest process, to do this sustainably and at quality."

Allowing DuPont to harvest likely is the most economical way for farmers to be involved. That's because square-baling equipment is expensive and building in labor costs of fall tillage at harvest can be costly and a "risky move," Pieper said.

Working against DuPont, he said, are continued doubts about the future of the Renewable Fuel Standard. The U.S. Environmental Protection Agency is expected to soon finalize volume numbers for three years that reflect an overall reduction in biofuels blended.

Cellulosic ethanol companies that have launched commercial production in the United States already have announced plans to build future plants in countries such as Brazil and China.

"We've seen farmers question whether this is for real (the long-term future of the Nevada plant)," he said. "They do wonder if we don't have a stable policy."


Sampson said stover harvest has led him to re-think crop rotations because of soil-health benefits. For one, in those fields where a top layer of residue was removed the ground froze deeper, he said, and it "worked up really nice" in the spring.

"If I could duplicate that by treating corn ground with less tillage that's huge," Sampson said. "I saw better yields with corn on corn with stover removed."

Sampson said he hopes to continue to rely on DuPont for harvest. A couple of years ago he harvested a bit of his own stover by pulling a square baler behind a combine. Because traditional harvest already is a pile of work, Sampson said he doesn't know if self-harvest is feasible.

Expanding stover harvest on his operation will depend largely on how his fields perform, he said. That will continue to grow as long as he can maintain a good combination of yields and moisture content.

Sampson said he used to follow soybeans with corn to take advantage of locking in nitrogen. Now, he said he noticed corn yields improving when he follows corn with corn on those stover-harvested fields.

As farmers continue to better manage residues through stover harvest, Pieper said it will help make way for expected higher-yielding corn plants.

"Iowa needs to be above 300 bushels when you get to an average," he said.

A 300-bushel average would allow DuPont to safely and sustainably harvest about 7.5 tons of stover per acre compared to about 5 tons at 200-bushel averages now, Pieper said.

The DuPont harvest, he said, is a pathway for Iowa farmers to reduce tillage and not leave heavy residues -- an eventual path to a more common use of no-till.

"What we've seen working with them is farmers are anxious and hungry about how to sustain their soils," Pieper said. "Every year counts. Most of this is very personal to them. We've had a couple of farms that have reduced tillage by 40% to 60%. Some have gone into strip or minimum till just because they're able. If we don't get rid of stover we can't do the next crop."

Pieper said farmer involvement with DuPont has remained consistent as about 87% of farms involved from the beginning have stayed on board.

As the Nevada plant continues to move toward complete scale-up, he said the challenge is to not only keep current feedstock providers interested but to attract new farmers.

Creating a market for corn stover in the Nevada area, Pieper said, will be just the beginning of new opportunities for farmers as a result.

"I compare it to the moon shot," he said. "We got way more out of that just sending a man to the moon. My excitement lies with farms learning to manage residues.

"I see this as a better opportunity. Farmers will be more efficient and improving long-term opportunities in ag."

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Todd Neeley