The shortage of available water could become the Achilles heel of the ethanol boom if more efficient use of water isn’t made a priority, finds a new paper by the Institute for Agriculture and Trade Policy (IATP)
The paper found that few states are monitoring water use at ethanol plants and public information is limited. Other findings from the report are:
There are currently no publicly available records on water use by ethanol plants in the U.S. In a review of major ethanol states, only the Minnesota Department of Natural Resources has public records on water use by specific plants.
Ethanol’s growth has been so dramatic that there are now concerns about the amount of corn available to meet various demands, including food, animal feed and export.
However, one of the most important emerging concerns is the consumptive use of water. Consumptive use of water is broadly defined as any use of water that reduces the supply from which it is withdrawn or diverted. Consumptive water use by ethanol plants largely comes from evaporation during cooling and wastewater discharge. As a rule of thumb, water utilization is 10 gallons per minute for each 1 million gallons of yearly ethanol production. Thus a typical 50 million gallons per year ethanol plant would need 500 gallons per minute of water [= 265 million gallons per year of water].
Minimal data is available on groundwater depletion, and the scope of future water availability is not clear. It will be to the benefit of the ethanol industry, and rural development initiatives in general, to get more clarity on the relationship between ethanol production, water consumption, and impacts on water supplies.
Figure 2 [graph above] takes Minnesota’s water consumption averages and applies them to national ethanol production estimates, which includes ethanol plants expected to come online through 2008. The result is a 254 percent increase in volume of water used in ethanol production from 1998 through 2008. If changes aren’t made, it is likely ethanol water use will see even more of an increase in the next decade.