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  Geotimes - December 2007 - Water problems ahead if ethanol continues to expand

Energy and Resources
Water problems ahead if ethanol continues to expand

A special National Academies National Research Council (NRC) committee that convened last summer found that a significant increase in ethanol production from corn could negatively impact water quality and availability in the United States, according to a report issued Oct. 10.

In his State of the Union address in January, President Bush called for the production of 35 billion gallons of ethanol per year by 2017, quite an increase over the 4.86 billion gallons of ethanol produced in 2006 (see Geotimes online, Web Extra, Jan. 25, 2007). If increases in the use of corn for ethanol production occur per the president’s and Congress’ plans, which included renewable fuels standards in its energy bills this year (see story, this issue), the harm to water quality could be “considerable,” the NRC committee said, affecting the nation’s water supply at both regional and local levels, especially in dry areas.

One factor that has to be considered, according to the committee, is that the same crop has different water requirements in different climates. For example, corn uses more water than soybeans and cotton in the Northern and Southern Plains, while the opposite is true in the Pacific and mountainous regions, due to the amount of rainfall and the hydroclimatic situation in the regions. If that isn’t considered, they said, water demands for drinking, industry, recreation, hydropower and fish habitats could be at odds with water demands from biofuels crops.

Ethanol refineries also use a lot of water and could cause shortages, the committee said. A refinery that produces 100 million gallons of ethanol per year uses the equivalent of the water supply for a town of 5,000 people, the report said.

Water quality is also a big issue: Groundwater, rivers and coastal waters could be significantly impacted by increased fertilizers and pesticides used in growing corn for ethanol, the committee said (see Geotimes, July 2007).

The committee did note that there are ways around some of these issues, through sound agricultural practices and technologies that reduce nutrient pollution and lower water use or reuse water, for example. But such practices must be in place before ethanol usage expands too much or there could be trouble, the committee said.

Megan Sever

"Bush renews call for renewable fuels," Geotimes online, Web Extra, Jan. 25, 2007 
"Peak Ethanol," Geotimes, December 2007 
"A blight on ethanol," Geotimes, July 2007 
"Agriculture consuming world’s water," Geotimes, June 2007 

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