Water and Wastewater dot com publisher Joe Taylor sent me a news release from the World Resources Institute suggesting that the stress on water supplies in the Southeast United States could be relieved through greater energy and water conservation.

Their newly released report, "Water for Watts," provides this chart of water use, based on U.S. Geological Survey data that shows about 65 percent--nearly 40 billion gallons of water--is withdrawn each day for thermoelectric power in the Southeast United States.

Since so much fresh water in the Southeast goes to feeding power generation boilers, the report suggests that reducing energy demand would also reduce water demand.

"Reducing electricity demands is not only critical to addressing our energy challenges, but also to meeting regional water needs," said Ben Taube, executive director at the Southeast Energy Efficiency Alliance and a co-author of the new report. "Lawmakers at the federal, state, and local levels should consider policies that create incentives for the efficient use of both water and energy, especially in light of recent droughts."

I checked with an application engineer at Pennsylvania Crusher, which provides coal crushers to about 80 percent of all the coal fired utilities in the US. He confirmed that nearly all older power plants use once-through systems that take water from a river or lake, or even the ocean, to use for cooling and then discharge heated water back into the same water system.

The "Water for Watts" news item didn’t address how much of the 40 billion gallons withdrawn daily by Southeastern utilities is returned. Whatever their net water use, once-through systems do have significant impacts on local aquatic environments, such as the fish and fish larvae caught in the water uptake and the impact of discharged heated water.

Closed-cycle cooling systems use up to 98 percent less water than once-through systems. In closed-cycle systems, cooling water is pumped through the power plant’s condenser and then through cooling towers. New power plants generally are required to have closed-cycle cooling systems. Older plants still using once-through systems might be required to convert to closed-cycle cooling when their water permits are up for renewal.

As the report points out, water availability has become a source of conflict between states in the Southeast. Alabama, Florida, and Georgia have fought over control of the Apalachicola / Chattahoochee / Flint River Basin and similar issues arose in North and South Carolina over the Catawba River.

The authors project that population growth in the Southeast could lead to a 30 percent increase in thermoelectric power generation by 2025: "Without policy action to encourage efficiency and water-efficient power production, this higher electricity demand could further exacerbate water scarcity problems."

Don Dunnington
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