The U.S. Environmental Protection Agency has approved using a higher blend of ethanol in gasoline for newer model cars. The E.P.A. ruling allows mixing up to 15% ethanol compared to the current 10%, but it only applies to vehicles manufactured since 2007. A decision on older models is expected later this year.

U.S. Agriculture Secretary Tom Vilsack says the ruling should provide more stability for the renewable fuels industry, but is unlikely to result in additional ethanol plants in Iowa. “Whether or not there will be new facilities in Iowa, I suspect they’re more likely to be modified as new feed stocks are identified as we can transition from corn to corn husks and corn cobs, that type of opportunity could require us to recalibrate and retrofit existing facilities,” Vilsack says.

Vilsack, the former Iowa governor, says new ethanol plants could be built in other states to meet demand. “Where I see the new construction taking place is primarily in the four corners of the United States, where bio-refineries currently do not exist but could exist with new feed stocks which and I think that is very important to the overall stability of the industry,” Vilsack says.

Vilsack says until other states are financially invested in bio-fuels Congress will be slow to support further incentives for the industry. Right now Iowa is the nation’s largest ethanol producer and is home to more than 40 active ethanol plants. Vilsack is in Des Moines to celebrate the World Food Prize.