The logistics of collecting and storing a million tons of corn stubble each year for an ethanol refinery are mind-numbing.
It would take 67,000 semitrailer loads to haul the baled stubble out of the field. That's 187 truckloads a day, or one every eight minutes. To complicate matters, the need for trucks, machinery and manpower would come during harvest, already the busiest time of the year on the farm.
And that's where a massive federal initiative into cellulosic ethanol may find its biggest bottleneck - on the farm.
"Naturally, the farmer says, 'Wait a minute. I've got enough stuff in my field,'" said Lex Thompson, president of the Imperial, Neb., Young Farmers and Ranchers Association.
The question is whether farmers will harvest and sell the nongrain plant material, known as cellulose or biomass, to make the federal government's plan for renewable fuels work.
The U.S. Department of Energy wants to replace 30 percent of the nation's petroleum needs with ethanol by 2030. That goal would require some 40 billion to 45 billion gallons a year from biomass ethanol, a technology not yet in commercial production.
"If we can get the farming community's support," said Andy Aden, senior researcher at the National Renewable Energy Laboratory in Golden, Colo., "then all the pieces are falling into place and some real progress can be made."
But farmer buy-in remains to be seen, said Imperial farmer Rod Johnson.
"Our main concern is $4-per-bushel corn (worth $750 to $800 an acre)," Johnson said. "Thirty dollars an acre for biomass is a minor concern for our operation."
The Energy Department wants researchers to develop a harvest and storage process that would provide material to a refinery for $35 a ton, a level that probably would make ethanol production profitable.
Opinions differ, however, on whether that is achievable. Some in the industry believe the cost to ethanol plants would be closer to $60.
Iowa State University researchers agree that the technology is not yet developed that will allow farmers to profit from harvesting some of their stubble for ethanol production.
ISU researcher Stuart Birrell and others have been experimenting with techniques that would allow farmers to reap and bale corn stubble simultaneously while harvesting corn.
That could lower costs significantly, Birrell said. "Every time you put another machine in the field, your costs really start going up."
Even with a one-pass system, Birrell said, the cost of harvesting would be greater than the $35 sought by the Energy Department. And there are other drawbacks. One-pass harvest experiments have slowed combines to about 60 percent of normal harvest speed, too slow to suit farmers, Birrell said.
"Our target is 80 percent of harvest speed," Birrell said. "We feel farmers would live with that."
Researchers are also studying how much of the corn plant can be removed without causing soil erosion and loss of soil nutrients.
There are advantages to leaving stubble in the field, Birrell said. "The bottom part is fairly high in nutrients."
Many of the questions surrounding cellulosic ethanol could be answered in the next 10 years as six pilot plants are built with the help of $385 million in grants from the Energy Department.
Some of those refineries will experiment with corn stover and other crop residues. Others will experiment with woody materials, others with switchgrass and others with municipal waste.
Right now, the cost of producing ethanol from corn stover is about twice the cost of producing ethanol from corn kernels.
"It cannot compete without subsidies," said Sam Tagore, a Department of Energy feedstocks specialist in Washington, D.C.
Not the least of the concerns with corn stover is the problem of storage, Tagore said. The harvest of corn stover would occur during a six-week harvest window in the fall, but the ethanol plant would require regular deliveries throughout the year.
Even a small ethanol plant using 2,000 tons of stover a day would require 100 acres stacked 25 feet high with stover to run a refinery for a year.
A three-year study in Chase County indicates that an 80-million-gallon ethanol plant would require corn stover from 500,000 acres of corn within a 50-mile radius of the plant and 500 acres to store it after harvest.
"That will give you an idea of the logistical nightmare this thing is," said Lex Thompson, one of the Chase County coordinators.
On the other hand, an additional $30 profit per acre would put $15 million into the pockets of farmers operating near the refinery.
The question, Thompson said, is whether such a scenario is feasible.
"We're at the stage now where we are going to know the answer in a few years," he said.
Imperial farmer Johnson, although still not sure what the future will hold, said there is potential for success.
"We believe there will need to be a return (profit) of $30 an acre for a farmer to want to participate," Johnson said.
That is the key, said Hettenhaus, the biomass consultant. "I compare farmers to the OPEC guys. They control the feedstocks. Unless it is a benefit to the farmer, forget it."
These are the six pilot projects awarded $385 million in grants by the Department of Energy to construct biomass ethanol plants:
Clearly, challenges remain to the commercialization of cellulosic ethanol, both in the fields and in the production facilities. It may be some time before someone finds a production model that works, from logistical, technological and economical standpoints.
I'm encouraged though by the number of pilot projects moving forward and the fact that each seems to be using a different set of feedstocks. I think this is important at this stage, as each feedstock will present different logistical and technological challenges and some may emerge first as more feasible feedstocks in the near term.
If we can find a few feedstocks that pencil out and work, they will give us the opportunity to work out technical and economic kinks on the production side while we continue to work on collection and transport methods that will make other feedstocks viable in the longer term.
Check out Robert Rapier's posts on the challenges facing cellulosic ethanol development over at the R-Squared Blog. I am personally more optimistic that these challenges will be solved, but Robert presents a good analysis of the hurdles still standing in the way of commercial cellulosic ethanol production. See posts here and here.
The industry still has a lot of work to do to become commercially viable. If it can, the potential is tremendous.
Cellulosic ethanol and plug-in hybrids together can likely replace all of our gasoline and diesel use for light duty transport (with ethanol providing the liquid fuel for plug-ins for about 1/3 of vehicle miles traveled, with the remainder running on electricity from the grid) while slashing our greenhouse gas emissions from transport.
This is my personal favorite for the future of transportation, and I hope that the logistical, technological and economic hurdles standing in the way of this future can be solved (and soon!).
[A hat tip to Robert Rapier of R-Squared Blog]