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Sinking Water and Rising Tensions
- Posted on December 5, 2007
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The problem is that droughts across the United States have decreased the pool of water now available to all concerns. Not only do utilities use it. So does big industry and small residential households. To compound the matter, the demand for electricity in this country is expected to rise by 2 percent a year over 20 years. Governments and businesses alike are now calling for concerted conservation efforts. Another approach being pushed is the development of new utility technologies that require less water.
Notably, there's a difference between "withdrawing" water and "consuming" water. In essence, utilities "borrow" water from lakes, rivers and reservoirs for cooling purposes during the production of electricity. But, they then return that water to its original source, albeit some of it will have evaporated in the interim.
"Overall, potential impacts on future freshwater withdrawals to meet forecasted increases in electricity generating capacity would appear to be relatively low, with most cases indicating a decrease in daily withdrawals," write Jeffrey Hoffmann, Sarah Forbes and Thomas Feeley, researchers with the U.S. Department of Energy's National Energy Technology Laboratory in an earlier report. "And while several (scenarios) project a significant increase in freshwater consumption by 2025 on a percentage basis, thermoelectric power plants would still likely represent only a small fraction of total U.S. freshwater consumption compared to irrigation and agriculture."
According to the report, the average thermoelectric plant uses 25 gallons of water to produce one kilowatt-hour of power using current technologies. If a household uses 1,000 kilowatt-hours a month, then 25,000 gallons of water must be withdrawn to provide that power from a coal-fired power plant. The number jumps to 31,000 gallons a month if nuclear power is used to generate that electricity. Natural gas plants, however, use much less water. By comparison, a typical household might use 10,000 gallons of water a month.
Most plants today use "once-through cooling" in which nearly all the water is returned to the source. Less than 1 percent is lost through evaporation or leaks in the system, says the Energy Department. Newer technologies use "closed loop" systems that rely on "cooling towers" and "re-circulate" the water. While that process uses much less water than prevailing technologies, considerably more water is "consumed" by the power plants. The department says more than 70 percent of the water withdrawn.
So why switch? A news story in the Atlanta Journal-Constitution points to Georgia Power's Yates plant. It is located on the Chattahoochee River and it once used about 477 million gallons a day in a "once through" system. By converting to a "closed loop" process, its water use fell to about 32 million gallons a day.
The West and Southwest have long been accustomed to the lack of rain. But, the Southeast is not, enduring heavy storms during its summer and fall. But, that eight state region is now suffering from a nearly 18 month dry spell and one that has pit neighboring states against one another. Watersheds are shrinking and they are competing for a dwindling resource.
Consider Atlanta, where the population is expanding and where more water that has been obtained from Lake Lanier and other bodies is needed there: That need conflicts with those of Florida and Alabama, which needs it for everything from running electric generators and manufacturing facilities to maintaining commercial fisheries and farm businesses. The U.S. Army Corps of Engineers is required by law to release some of that water not only so others may use it but also because the fish need it to survive.
The dilemma is that Georgia's water levels are down about 14 feet from their normal seasonal levels, forcing its governor to declare a state of emergency in certain parts of the state. Because Georgia wants more water for itself, its neighbors are feeling the effects. Alabama's Governor's says that any restrictions on water flow would impede electricity production at the Farley Nuclear Plant that is located there and which creates power for 800,000 residents in three states.
But, the Army Corps of Engineers says that reduced rainfalls mean that it must cut the water flow out of natural basins. It has therefore sided with Georgia's governor, who says that if his state's water is diverted then Atlanta would have would have to receive water deliveries from the Federal Energy Management Agency. "If the corps does not hold back some water now, and if extreme drought conditions continue, it is possible there may not be enough water in storage next summer to meet the needs of users."
Estimates are that the region needs 40-50 inches of rain to get back to normal. That may take some time. But, in any event, the emphasis needs to be on water conservation. A study cited by the Atlanta Journal-Constitution and performed by the Georgia Environmental Facilities Authority found that aggressive statewide conservation efforts could save 164 million gallons per day by 2015. Of that, 159 million gallons would come from slowing the rate of power consumption, the paper reports.
Any exacerbation of the current water shortages in the Southeast will weigh heavily on all concerns and particularly on utilities that require large quantities of water to produce electricity. Newer technologies will eventually alleviate some of the pressure there and elsewhere. But, the whole issue underscores why energy efficiency must become a focal point of American public policy.
Monday's (Decenber 3rd) edition of the EnergyBiz Insider contained some misleading information. The next round of global climate change discussions, which will take place in Bali, Indonesia, will highlight the findings of the Intergovermental Panel on Climate Change. The report predicts 1.8 to 2.8 degrees increase in temperature by 2090 to 2099 for the most accepted scenarios. It also projects an 8 inch to 16 inch rise in sea levels over the same period. Other experts say that temperatures could warm 5 to 8 degrees Fahrenheit by 2100 if carbon dioxide concentrations in the atmosphere reach twice the levels of those in the Industrial Revolution.
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