BioFuels Journal

By Susan Reidy, BioFuels Journal Editor

Without some careful planning, water availability could stand in the way of growing the ethanol industry, according to a new paper from the Institute for Agriculture and Trade Policy (IATP).

The paper, “Water Use by Ethanol Plants, Potential Challenges” released in October by the IATP, Minneapolis, MN (612-870-0453), found that few states are monitoring water usage and there is little public information available.

“Despite steady improvements in the efficiency of water use in ethanol plants, the sheer number of new ethanol plants being built has the potential to put a strain on the Corn Belt’s water resources,” said Dr. Dennis Keeney, IATP senior fellow, who authored the paper with Mark Muller, director of IATP’s environment and agriculture program.

“The good news is that much of ethanol’s water demands can be met with appropriate planning. But that planning is currently not happening at the level it needs to.”

Water Availability

Conflicts over water use are growing in the Midwest, the paper reports. Large livestock confinements, crop irrigation, and ethanol plants are all competing for the same supply.

The effects of ethanol production on groundwater vary locally and are affected by several factors including volume used, properties of the aquifer, other uses, and rate of aquifer recharge.

Water availability in the Midwest is a local rather than a regional issue, and will vary over time, according to the paper. It will be up to local government to protect local water supplies from undue exploitation.

Ethanol Plant Water Usage

Consumptive water use by ethanol plants largely comes from evaporation during cooling and wastewater discharge, the paper said. Consumptive water use is defined as any use of water that reduces the supply from which it is withdrawn or diverted.

Generally, an ethanol plant will use 10 gallons of water per minute for each 1 million gallons of ethanol produced. A typical 50 million gallon plant, would need 500 gallons per minute of water.

There are no publicly available records on water use by ethanol plants in the United States, the authors found, with the exception of the Minnesota Department of Natural Resources.

Minnesota plants use a range of 3.5 to 6 gallons of water per gallon of ethanol. Average water use has declined from 5.8:1 in 1998 to 4.2:1 in 2005.

Authors of the paper said 4 gallons of water per gallon of ethanol is a good estimate with the current technology.

Applying that number to the amount of ethanol production expected to come online in 2008 would result in a 254% increase in the volume of water used in ethanol production from 1998 to 2008.

Much of the Corn Belt has plentiful water supplies, the paper reported, but regions such as the greater Chicago area, Western Iowa, and Nebraska, may run into competing water uses.

Water availability will challenge the ethanol industry in many regions, the paper said, particularly west of the Missouri River.

“We’ve already seen a few communities reject ethanol plants because of concerns about water usage,” Muller said.

“Rural communities have been very supportive of ethanol production because it uses local corn and often has the support of local investors.

“If ethanol’s water consumption leads to disputes in local communities, that good will toward ethanol may disappear.”

Recommendations

The paper outlines several recommendations for reducing ethanol’s water consumption:

--Maintain and strengthen regulatory oversight by state and local governments on the siting of ethanol plants, with special emphasis on the water supply and availability.

--Where feasible, site plants adjacent to municipal wastewater facilities. This type of wastewater, which would otherwise be discharged to surface waters, can easily be used by an ethanol facility, the paper said. This could also lower the plant’s energy costs by reducing water pumping.

Drawbacks include the resistance to siting plants close to cities, and the reduction of discharge to streams that need wastewater to maintain minimum flows.

--Look for water recycling opportunities with livestock facilities.

--Place a greater economic value on water. Policymakers should use regulation, taxes, and economic incentives to create a business climate that promotes greater water efficiency, the paper said.

--Maintain publicly available records on ethanol’s water consumption.

For a link to the complete report, see below.

See Related Websites/Articles:

• Water Use by Ethanol Plants, Potential Challenges

more TOP STORIES...