The ethanol industry is a thirsty business, with the average U.S. ethanol plant requiring about 300 million gallons of water every day for processing and cooling equipment, according to the Renewable Fuels Association (RFA). That's equivalent to the water supply for a town of about 5,000 people.
This daily need for water has some ecologists and state officials wondering about the effect on water supplies in areas where there is already high demand for water.
In Minnesota, for example, the state now orders full environmental reviews on proposed ethanol plants, citing concerns about water availability. At least one proposed plant, near Pipestone, did not get built because of worries about the lack of water to run it.
The good news is that water issues are forcing ethanol plants to grow more efficient. U.S. ethanol facilities today are using 27% less water than five years ago, according to a study by the U.S. Department of Energy. Meanwhile, ethanol production has increased 276% in that time frame.
Technology wins out. The dramatic improvements that have been seen in dry-mill ethanol production demonstrate the industry's commitment to developing the most efficient technologies available, says Bob Dinneen, RFA president and CEO.
Water usage in biorefineries is declining as ethanol producers increasingly incorporate water recycling and develop new methods of converting feedstocks to fuels that increase energy yields while reducing water use.
"Water recycling technology today is light-years ahead of where it was when many ethanol plants started,” says Jeff Gross, global marketing manager for biorefining at Ashland Hercules Water Technologies, which supplies products and process improvement technologies to ethanol facilities. "Today, we are able to retrofit plants to help them reduce water usage by 20% to 30%.”
It makes good business sense for ethanol plants to lower their water usage, Gross adds. With new water technology and minor process enhancements, facilities can significantly lower not only their water usage but also their costs, he says.
New ethanol plants use about 3 gal. to 5 gal. of water for each gallon of ethanol that is produced, according to the Nebraska Center for Energy Sciences Research. Newer plants also are designed to recycle 80% of the water they use so they are not continuously drawing fresh water.
Not that much water. At the end of the day, the amount of water used by ethanol plants on a state level is just not that huge, says Monte Shaw, executive director of the Iowa Renewable Fuels Association. Iowa is the leading state for ethanol production, with 42 ethanol facilities.
"If you look at the permitted water use in Iowa, all of the industrial groundwater permits account for less than 5% of water use,” Shaw says. "Ethanol is just a small part of that pie. We're just not that big a user of water statewide.”
To place this situation in a familiar context, Shaw likes to point to the fact that it takes 150 gal. of water to produce the average Sunday newspaper, according to figures from the U.S. Geological Survey and the Environmental Protection Agency.
"So for every editorial written against ethanol, we could have another gallon of ethanol,” Shaw says.
You can e-mail Jeanne Bernick at firstname.lastname@example.org.
- Early Spring 2009