Ethanol has brought the biggest changes to agriculture since the plow, some say. Yet, much larger changes lie ahead as the industry evolves to using cellulose feedstocks, says Jill Euken, Iowa State University (ISU) Extension field specialist for the Center for Industrial Research and Service.

“The 2007 Energy Bill mandates 21 billion gallons of cellulosic ethanol annually by 2022, plus 15 billion gallons annually derived from grain — about double what is produced now from corn,” Euken says.

A feasible timeline of how this transition might evolve has been developed by Larry Johnson, ISU director of Iowa State's Center for Crops Utilization Research:

Year Ethanol Feedstock

2010: Cornstarch, bran*

2012: Cornstarch, bran, cobs

2015: Cornstarch, bran, cobs, stover

2020: Cornstarch, bran, cobs, stover, dedicated cellulosic crops

*Bran is the hull of the corn kernel and a fairly dense source of energy — much more so than stover. Bran previously went into the DDGS in grain-based ethanol processing.

Although much of the ethanol refinery technology remains to be developed, one thing is clear: Farmers in some parts of Iowa will soon harvest corn cobs along with their grain as ethanol feedstocks, Euken predicts.

Cobs are the logical first step in the transition to cellulosic ethanol, Euken says. Their harvest can be integrated into one pass along with grain harvest, they yield more ethanol than the rest of corn stover and they're easier to transport than bulkier grasses.