Grain Bins


Looking into Ethanol’s Water Use

Posted on March 09, 2010

In discussing the Pro’s and Con’s of ethanol, a hot topic is always how much water it takes to produce a gallon. It might sound alarming at the time, but it never hurts to look further into the matter.

“There’s too much attention on water usage by ethanol plants,” says Sangwon Suh, assistant professor, Bioproducts/Biosystems Engineering, University of Minnesota.

Ever increasing improvements in technology have allowed ethanol plants to use less than 4 gallons of water/gallon of ethanol today, down from 10 gallons a couple of decade ago.

Below are a few examples of water usage that should put things in perspective:

One latte = 53 gallons

One cotton t-shirt = 400 gallons

One barrel (32 gallons) of beer = 1,500 gallons

One pair of blue jeans = 1,800 gallons

One ton of steel = 62,000 gallons

The amount of water needed to produce a gallon of conventional oil can be anywhere between 3-5 gallons of water on average. Oil produced from tar sands, like in Canada (where the United States gets a majority of its oil), uses eight gallons of water per gallon of oil doubling that of corn ethanol.

In most cases, an ethanol plant’s process water is not discharged from the facility, but recycled and reused by the boilers. Water that does leave the plant is treated and reused elsewhere or may leave the plant as part of the byproduct called distillers wet grain, a high protein livestock feed.

Biotechnology is also improving our future water use in the development of drought tolerant corn, which would cut down on the amount of irrigated acres. Although the National Renewable Energy Laboratory estimates that 96 percent of all the corn used in ethanol production already comes from non-irrigated acres.

Renewable Fuels Association President, Bob Dinneen, said, “Ethanol producers are investing in new technologies that reduce water use, improve efficiency, and employ feedstocks in addition to grain for ethanol production.”

This increase in ethanol efficiency is providing a cost-effective, home-grown, renewable fuel giving consumers freedom of choice at the pump to both better our environment and economy.

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