Water Quantity Implications of Ethanol Production in the United States.

The 4-fold increase in distilleries producing corn-based ethanol has created demands for processing and cooling water that often have not been anticipated by the local governing body when permitting these plants. Currently 143 plants are operating nationwide with total capacity of 8,160 mgpy and an estimated 5, 245 mgpy of capacity will be coming online. Twenty of the plants are located on the High Plains bedrock aquifer. It requires about 4 gallons of water to produce one gallon of ethanol. Several permits for ethanol plants have been denied or put into litigation because of this water need, which usually comes from groundwater supplies. Usually there are other demands on the water, such as municipal or industrial; city/regional planners are not certain there will be enough to go around. The ethanol industry has significantly increased the efficiency of water use since the first plants, but no current data are available to show they have achieved efficiencies beyond what we found in 2005. It is likely that the next generation cellulose ethanol plants will not be any more efficient, and may require up to 9 gal water per gallon of ethanol. There are few if any policy options available to improve on water efficiency in ethanol plants other than to place in the current mandates and incentives a requirement that ethanol plants sharply reduce water use. Perhaps a water efficiency requirement will spur research and development by the industry. However, if an industry is using more water than the community can provide without curtailing other more essential operations, tensions will rise. It may come to down to who really owns the water, the citizens or the industry.