By DOUG SCHMITZ
Iowa Correspondent

JOHNSTON, Iowa — A new University of Minnesota study has found Midwest states use less water in their respective ethanol production than those in Western states, with Iowa – the largest corn and biofuel producer in the nation – using the least, at six gallons of water per ethanol gallon, to California’s 2,100 gallons of water.

“We are glad to see that the study recognized our decreasing use of water to produce ethanol,” said Mindy Williamson, communications and public relations director for the Iowa Corn Growers Assoc. and Iowa Corn Promotion Board (ICGA/ICPB).

“We see that technology is only improving to make that number even smaller and much of the water used today in the ethanol process is recycled through the plant,” she said about the results of the study, published in the April 15 edition of the American Chemical Society journal Environmental Science and Technology.
It is the first report of its kind to compare water use in corn-ethanol production on a state-by-state basis. According to the National Renewable Energy Laboratory, the average production of one gallon of ethanol requires three gallons of water.

“To give people perspective, a five-minute shower uses between 25 and 50 gallons of water and it takes over 28,000 gallons to process cane into table sugar,” Williamson noted. “By everyday standards, ethanol production, especially in Iowa, is efficient and will only continue to improve.”

Funded in part by the U.S. Department of Energy and by the Legislative Citizens Commission on Minnesota Resources, the study’s authors used agricultural and geological data from 2006-08 to develop a ratio showing how much irrigated water was used to grow and harvest the corn and to process it at ethanol plants.

According to UM researchers, ethanol production in Iowa and Minnesota uses far less water overall than similar processes in states where water is less plentiful, such as California. Minnesota, which in 2007 produced about a third as much ethanol as Iowa, uses about 19 gallons of water per gallon of ethanol.

Moreover, the report said states such as California, where irrigation is needed to grow corn, fared far worse than those where almost no corn is irrigated. The state, which only produces a minimal amount of the nation’s ethanol but irrigates most of its corn, is the largest water consumer, at about 2,100 gallons of water per gallon of ethanol; South Dakota, with total production roughly equal to Minnesota’s, uses about 96 gallons of water to produce one gallon of ethanol.

The study said Kentucky uses seven gallons of water; Illinois uses 11; Indiana uses 17; and Michigan uses 47. But while Iowa currently leads with the least amount of water used, among the ethanol-producing plants in 2007, Ohio had the lowest with five and California had the highest, with 2,138 gallons.

The study also said U.S. ethanol production required about 861 billion gallons of water – usage that could be a determining factor in policy decisions about where ethanol plants are built, which the authors added “highlights the need to strategically promote ethanol development in states with lower irrigation rates and less groundwater use.”

Sangwon Suh, an assistant professor in the university’s Department of Bioproducts and Biosystems Engineering and the study’s lead author, said all states with high water usage ratios as classified by the federal government would likely experience water shortages in coming years.

“Both energy security and water security are too important; improvement of one of them should not be made at the expense of another,” Suh said. “Understanding the dependence of biofuel on water and its spatial disparity will be critical in implementing the biofuel policy in the United States.”

To reduce the water requirements to meet the 57 billion liter conventional biofuel production mandate by 2015 under the Energy Independence and Security Act of 2007 (EISA), the study’s authors said the expansion of corn ethanol production needs to take into account regional or county-level water use practices.

“Our study highlights the need to strategically promote ethanol development in the states with lower irrigation rates and with less fossil groundwater use,” the authors said.

One example of an ethanol plant that’s working on just that is POET’s 35 million-gallon-per-year facility in Bingham Lake, Minn., which POET says has dramatically cut water usage, using a zero-liquid discharge process which doesn’t release water into the atmosphere.

In fact, POET Biorefining in Bingham Lake stated it has already used less water than the industry average, with only 3.42 gallons of water to produce one gallon of ethanol. With zero-liquid discharge, POET CEO Jeff Broin said that rate is cut by 23 percent, to an estimated 2.64 gallons of water per gallon of ethanol.