Producing a significant amount of ethanol strictly from corn cobs is possible but would require a specific set of circumstances to be economically feasible. In a report released by Purdue University’s Department of Agricultural Economics, researchers concluded that harvesting corn cobs for use as an ethanol feedstock would only prove fiscally advantageous for farmers should a combination of factors coincide. The paper went on to note that the current government incentives for a possible cob-based advanced biofuel would offset collection costs enough to make this an attractive fuel source.
“As we explore innovative ways to use corn, our most abundant feedstock, to produce renewable energy, we have to remain flexible and dedicated,” says National Corn Growers Association Ethanol Committee Chair Jon Holzfaster. “Currently, our society places an extremely high priority on developing alternative fuel sources. New cob-based biofuel continues our tradition of working towards the goals of the RFS2, keeping our resources at home and developing new jobs in the U.S.”
In their work, Matthew Erickson and Wallace Tyner determined that factors such as corn yield, farm size, harvesting equipment rental costs and increases in harvest times greatly affected the price per ton.
Concluding the paper they state, “cobs will be more expensive than previously believed – maybe too expensive to be used for energy production unless the public is willing to further support development.”
Corn cobs offer a particularly attractive feedstock option, as they would meet EPA standards established for cellulosic biofuels in the Energy Independence and Security Act and count towards the RFS2. At the same time, corn cobs have minimal nutrient content therefore removal has no substantial impact on soil nutrient content.
In assessing the economics of cob harvesting the researchers focused on three critical factors: the decrease in harvest work rate cob harvesting necessitates, the expense of cob wagon rental and the percentages of cob in residue. Repeatedly, data showed that the market must expect higher value from cobs to realize it as a feedstock for an advanced biofuel.