Officials hailed Iowa as the hub for a new generation of energy production last week at the long-awaited grand opening of Project Liberty’s cellulosic ethanol plant in Emmetsburg.

The facility, a joint venture of Poet and Royal DSM, will process baled corn cobs, leaves, husks and stalks into ethanol at a rate of about 2 million gallons per month. It is the largest commercial cellulosic ethanol facility in the U.S. and first to use corn...