A recent study from the University of Minnesota claims that ethanol production is resulting in a dramatic increase in water use, larger than was previously thought. However, by looking at water use in isolation, the report fails to take into account numerous factors that must be part of the water use discussion.
“Expansion of America’s renewable fuels industry is occurring with the most efficient use of natural resources like water in mind,” said Renewable Fuels Association President Bob Dinneen. “Ethanol producers are investing in new technologies that reduce water use, improve efficiency, and employ feedstocks in addition to grain for ethanol production. It is important that these worst-case scenarios offered by the University of Minnesota are not allowed to overshadow the improvements being made in farming and renewable fuel technologies.”
Context is critical when discussing water use. Notably, the paper fails to mention or explore in depth key factors including:
The National Renewable Energy Laboratory estimates that 96 percent of all the corn used in ethanol production comes from non-irrigated acres. Moreover, less less than 15% of the total corn crop is irrigated.
In addition, that vast majority of ethanol production and expansion relies on corn produced where irrigation is the exception and not the rule. The report makes much of its suggested water use for ethanol production in California. This paper fails to account for the fact that virtually all of the corn for ethanol production in California comes from the Midwest, not California.
The paper provides no comparison or context with respect to other fuel sources. The water profile of petroleum, for instance, is getting dramatically worse as tar sands and other marginal sources of petroleum gain greater market share.
The paper exclusively focuses on ethanol production and ignores the livestock feed co-product of the process. The U.S. ethanol industry produced enough livestock feed in 2008 to displace all the corn used to feed cattle at feedlots in Texas, Kansas, Colorado and Nebraska where irrigation is more common. Additionally, a growing portion of the livestock feed co-product is being sold as a wet product, displacing some of the water livestock would consume if they had been fed a dry product made from irrigated corn.
New technologies are making ethanol production more efficient. Since 2001, water use at ethanol biorefineries is down by more than 26%, with some plants experiencing even greater reductions. The use of wastewater from municipalities or other sources is a technology that more and more ethanol producers are looking at to reduce the need for groundwater.
Strict water use standards exist, especially in the more arid Western states. Ethanol facilities are not permitted or built where water supplies are not sufficient.
More on water and ethanol production can be found at Renewable Fuels Association.