Currently, Iowa's floodwaters have halted the production of 300 million gallons of ethanol. Another 100 million gallons could end later this week depending on the rivers' cresting stages. The state has the capacity to produce 2.2 billion gallons of ethanol annually.

The temporary production halt will reduce the state's corn demand for ethanol by more than 300,000 bushels a day, reports Iowa's Renewable Fuels Association. Officials add that "it will be some time before production can return to normal levels."

The recent run-up in corn prices also could force some ethanol distilleries to close their doors. According to a Reuters' report, ethanol producers are losing about 8 cents on every gallon. That's  down from a 20-cent-per-gallon profit that distillers were seeing just two weeks ago.

Already five "small- to mid-size distilleries" have ended production because of corn costs.
There are 154 ethanol distillers nationwide. Glenn Grimes, University of Missouri agricultural economist, says he expects more refineries will be closed in the next year or more.