In the face of criticism about ethanol, delays in the commercialization of advanced biofuels and the recent development of domestic supplies of fracked gas and petroleum, some people are asking, "Why are we producing biofuels?"

The answer, quite simply, is that we have few other options for achieving a sustainable energy future. Besides quality and cost, future fuels will have to meet additional metrics including environmental, social and political sustainability.

Biofuels are transportation fuels produced from biomass, which is the generic term for any kind of plant material used as an energy source. Corn ethanol and soy biodiesel were the first to emerge. The first decade of the 21st century witnessed an unprecedented boom in the U.S. biofuels industry with fuel ethanol production increasing by a factor of 10.

This was only the beginning of a national...