Oct 23 - McClatchy-Tribune Regional News - Bruce Henderson The Charlotte Observer, N.C.

The Catawba River's biggest water user faces no withdrawal limits, answers to no local authority and allows 73 million gallons a day to vanish into thin air.

Duke Energy's five coal-fired and nuclear power plants gulp billions of gallons of water a day, drought or no drought. Most of it is returned to the river after cooling the steam that spins the plants' turbines.

But a lot of water evaporates as vapor after absorbing the steam's heat.

Duke's plants lose almost five times as much Catawba water as Charlotte-Mecklenburg Utilities, which returns most of the water it draws as treated effluent.

With the Carolinas enduring the second record-setting drought in five years, every drop of water used by a home or an industry faces heightened scrutiny.

As Duke prepares its first coal-plant expansion in more than 30 years, some critics -- and the power industry itself -- question whether there's a better way.

The 800-megawatt boiler Duke plans to add to its Cliffside plant, on the Broad River in Rutherford County, illustrates the choices, none of them perfect.

Cliffside challenges

Cliffside, including four 1940s-vintage boilers to be retired, pulls 280 million gallons a day from the Broad. The cool water condenses steam and goes back in the river.Two problems: Fish get sucked into the plant's river intakes. And the discharged water is 20 degrees warmer than before, which can hurt the ecosystem.

The solution, to be installed on the new boiler, is called a cooling tower. It works by circulating the hot water through material cooled by air. Cooling towers need much less river water. The expanded Cliffside plant will draw 88 percent less water from the Broad despite producing 80 percent more power.

But evaporation will double to 19 million gallons a day.

Even without power plants, evaporation robs the Catawba of water. About 300 million gallons of Catawba water -- more than power plants, towns and industries consume together -- turns to vapor on a 95-degree day.

A dry, but costly, option

More than 60 power plants, the industry-supported Electric Power Research Institute says, use alternative "dry cooling" that transfers heat to the air without huge volumes of water.

The technology costs up to four times more and eats into the amount of power generated.

That's why Cliffside won't use dry cooling, said Harry Lancaster, Duke's director of new generation projects. The plant's design does include methods to save water in other ways, he said, such as recycling water from the cooling tower to the "scrubber" that captures the air pollutant sulfur dioxide.

Neither the N.C. Division of Water Quality nor the state Utilities Commission evaluated whether Cliffside should use a water-saving alternative.

But scrutiny of the industry's water demands is growing, the research institute says. The institute is researching ways power plants can save water, such as by recapturing vapor from cooling towers.

"One of our objectives is to make the technology less costly and to reduce the energy penalties associated with it," said Bob Goldstein, an institute official in Palo Alto, Calif.

One group asking questions is the N.C. Waste Awareness and Reduction Network, which last week filed a legal challenge of Cliffside's wastewater permit. The group said state regulators failed to analyze how the plant's water use, in combination with other users, will affect the Broad River.

The Broad ran Monday at one-fourth its average flow. Water availability "is becoming an increasing problem" for many users of the river, the N.C. Wildlife Resources Commission said in commenting on the Cliffside expansion.

If a rumored reservoir is built in nearby Cleveland County and Duke follows through on a proposal to build a nuclear plant downstream in South Carolina, said WARN attorney John Runkle, "there's not going to be any water left in the Broad."

Conservation efforts under way

Duke says it has already taken its best shot at conserving water -- shutting off its hydroelectric stations.Since March, at the first hint of drought, hydro generation has been reduced 63 percent compared with the previous four years.

An 81 percent reduction in the water released from Lake Wateree, at the end of the Catawba system, saves almost 2.2 billion gallons a day.

"The biggest impact we could possibly have has already occurred," said Steve Jester, Duke's vice president for hydro licensing and lake services.

Today

Duke Energy is expected to set an estimated date for tougher water restrictions.