Standing in front of three large bales of crop residue, Jan Konincks, business director, biofuels, DuPont, states an interesting fact. "These three bales would provide the feedstock for [the new plant] for three minutes," he notes.

That's right three large 3x3 square bales of stover are about 3 minutes of work in the new cellulosic ethanol plant DuPont is building near Nevada, Iowa. Working with Lincoln Way Energy, the new plant has already lined up suppliers of stover. The plant will draw from about 190,000 acres of corn within a 40 mile radius of the plant.

Sounds like a lot of acres, but it turns there about 875,000 acres of corn in that area, so they're pulling from less than 25% of the available corn acres. The plant will burn through about 590,000 bales in a year to produce 30 million gallons of ethanol. Cost of the plant is about $200 million, or about $7 per gallon - though that's not the cost of production.

Jeff Taylor, a Lincoln Way Energy board member and Iowa farmer, notes that to price the residues, DuPont is estimating the nutrient removal represented by the bales. "They took core samples to measure nutrients in each bale," he notes. "They'll pay for the lost nutrients and for a little more."

Keep up on biofuels and the industry with Lynn Grooms.

Whether the plant will pull cores from all bales in the future is not clear - in a truly commercial setting - that would probably not be necessary. And this will evolve over time.

Add it up and they're talking about 375,000 tons of stover through the plant. But a standing crop of corn producing more than 200 bushels per acre generates plenty of material.

In fact, during a media event this week, DuPont showed a trial area where a simulation was conducted for different residue levels and how it impacts the following crop. DuPont and DuPont Pioneer are taking precautions up front to avoid the onus of taking off too much material and hurting development of organic matter on that corn ground.

Yet they find in higher-level corn production the leftover residue can be a challenge. In the trial, they had corn planted in a section to simulate the residue left by a 90-bushel crop, a plot simulating following a 180-bushel crop and then a 360-bushel crop - which if Pioneer stays on track they'll hit on average by 2050.

The crop with the highest residue levels showed visible signs of being behind other plots, and managing high-yield corn on corn will require managing residues. Below we've summarized the numbers for that new Commercial Demonstration Plant:

Cellulosic ethanol stats - DuPont Commercial Demonstration Plant - Nevada, Iowa - opening 2014

190,000

No. of acres needed to supply the 30-million-gallon plant.

875,000

No. of acres in the 40-mile radius of the plant (the plant will not need all crop residues to operate)

590,000

No. of bales to operate for a year - large square bales.

375,000

No. of tons of residue needed per year.

$200 million

Capital cost for the plant.