Researchers at the University of Minnesota reported recently that the production of ethanol fuelstocks may consume as much as three times more water than previously thought, depending on where they’re grown.
They found that ethanol fuelstock grown in Iowa uses the least water — about 6 gallons of water for each gallon of ethanol. While fuelstock grown in Minnesota uses about 19 gallons of water per gallon of ethanol.
And that’s just on the farm. The researchers found that total water use in the production of a single gallon of ethanol is up to 2,100 gallons of water — from farm to fuel pump — depending on the regional irrigation practice in growing corn. Although a dozen states in the Corn Belt consume less than 100 gallons of water per gallon of ethanol, making them better-suited for ethanol production.
Annual bioethanol production in the U.S. is about 9 billion gallons, according to the University of Minnesota researchers, who published their findings in an article titled “Water Embodied in Bioethanol in the United States” in the April 15 issue of the American Chemical Society’s journal.
Previous studies estimated that a gallon of corn-based bioethanol requires 263 gallons to 784 gallons of water from the farm to the fuel pump. Trouble was, those estimates were calculated without considering regional irrigation practices.
No doubt water usage needs to be weighed in policy discussions involving the location of ethanol plants. If not, there’s a good chance we’ll see ethanol plants about as sensible as an ice factory in the Mojave Desert. It’s important for policymakers to scratch from their lists those regions that have high water-usage ratios. Let’s instead steer them to places like Idaho, to encourage a smarter and more sustainable approach to biofuels. By Lee Bruno