Stover experiments critical to Iowa’s future in biofuel
Source: Dan Piller • Des Moines Register • Posted: Friday, November 18, 2011
“Corn stover is a lot harder to work with than hay, which can be cut and bundled pretty easily,” says Rod Phelan of Power Stock, shown at a farm near Ames this week. “Stover is a lot harder to crush and grind.” / David Purdy/Register photos
GILBERT, IA. — If Iowa hopes to remain a leader in the next generation of biofuels beyond corn-based ethanol, it must figure out cost-effective ways to pick up the cornstalks and leaves left behind at harvest.
That is what several machines have been doing on fields in northern Story County this fall to practice gathering for a noncorn or cellulosic biomass ethanol plant that DuPont will open by 2013 near Nevada.
The same exercise has happened the last three years in a 35-mile radius around Emmetsburg, where Poet of Sioux Falls, S.D., has begun work on a cellulosic plant scheduled to open in 2013.
“Instead of drilling for oil, we’ll be collecting corn stover after harvest,” said Steve Mirshak, business director for cellulosic for DuPont, which owns seed producer Pioneer Hi-Bred of Johnston.
The outcome of the stover-gathering experiments is crucial. Iowa has taken the early lead in biofuels, with 41 corn-fed ethanol plants that this year will produce almost one-third of the 14 billion gallons of ethanol mixed into motorists’ gas tanks.
But corn ethanol has attracted a host of critics, from hunger activists opposed to the use of food as fuel in the face of starvation to livestock producers annoyed by record feed costs.
The federal renewable fuels mandate calls for one-half of the 36 billion gallons of ethanol to be produced by 2022 to come from noncorn feedstocks. The solution is cellulosic ethanol made from stover, wood waste, tall grasses and other sources, supporters say.
More stover than ever is left behind. A typical Iowa cornfield has increased its plant population by at least one-third to more than 30,000 plants per acre in the last two decades.
Corn-fed ethanol’s delivery logistics were easy enough, almost identical to delivering corn to a grain elevator. Not so with biomass.
DuPont has contracted with Story County farmers to pick up their stover. The company is tight-lipped about what it is paying, except to say that the price is “competitive.”
The farmers supplying stover for Poet are getting around $80 per dry ton, half of which is coming from a U.S. Department of Agriculture program that is now under review in the discussions over the farm bill.
“Quite a bit of that government money is a bonus for early adapters,” said Jim Sturdevant of Poet. “The final market price for stover probably will be lower.”
Sturdevant said Poet’s contractors have picked up about one-quarter of the stover on farm fields, which helps ethanol plants sidestep the early qualms some farmers had about giving up the crop residue that normally is disked back into the soil as a nutrient.
“This is a whole new process, and we are examining the different ways to do it,” said Harrison Petit, vice president of business development for Power Stock, which hopes to be the stover-gatherer for the 27.5 million-gallon ethanol plant that DuPont will build next year.
DuPont and Power Stock have gathered bales using a two-step system that first grinds the stalks and leaves into smaller pieces and lines them up in rows. A heavy-duty baler gathers the pieces and puts the stover into neat bales that can be stored.
A plant like DuPont’s will need 60,000 bales of stover when it opens in 2013. The biomass has to be clean and it can’t mold. DuPont and Iowa State University’s Biocentury Research Farm west of Ames are experimenting with different ways to keep the stover in usable condition for months after it is picked up.
The DuPont and Poet projects are two of three projects in Iowa working with farmers to pick up and bale stover for eventual use as an ethanol feedstock.
In eastern Iowa, Deere & Co., Monsanto and Archer Daniels Midland have worked on a stover-gathering experiment on Amana Society fields in Iowa County.
They’ve all learned the same thing: While the process looks like hay baling, the hardy stalks and thick leaves from corn plants don’t yield as easily to cutting and baling as fresh Iowa hay.
“Corn stover is a lot harder to work with than hay, which can be cut and bundled pretty easily,” said Rod Phelan of Power Stock. “Stover is a lot harder to crush and grind.”
The stover has to be kept clean, so that the fuel made from it won’t be contaminated, no small challenge when the biomass has to be picked up off the ground.
Any farmer who stores corn knows its vulnerability to mold and insects. Stover is no different.
ISU’s Biocentury Research Farm is experimenting with different ways to store the bales, inside hoop barns or under the white plastic tarps similar to those used by grain elevators to protect dumped corn.
“Normally farmers disk the stover back into the ground after harvest to use as a soil nutrient,” said farmer Jeff Taylor, on whose land much of the DuPont experiment has taken place.
Taylor picked up and delivered some corn stover last year in DuPont’s first collection efforts. He said he made a pleasant discovery: Removal of some of the stover not only made planting easier the following spring but also helped yields.
“I got some 200 bushels per acre on a corn-following-corn field that was picked up after last year’s harvest, and that is unusual,” said Taylor, who has more than passing interest in ethanol as a member of the board of Lincolnway Energy, a corn-fed ethanol plant already operating in Nevada .
While most stover will be picked up in October and November at the end of harvest, most of it will go into storage for months while steadily feeding the ethanol plant.