Water-related limits on energy production are happening throughout the United States, even here in Tennessee, where water availability is generally taken for granted. For example, Governor Sundquist imposed a moratorium earlier this year on the installation of new “Merchant” power plants because these highly efficient, natural-gas-fired turbines require large amounts of water for cooling. Whether some of the proposed power plant sites can provide sufficient water without adversely affecting other water users is questionable.
In the Tennessee River basin, water temperature may limit future energy production. For example, because the Tennessee River runs shallow and warm at Muscle Shoals, Alabama, where cooling water is withdrawn for the Tennessee Valley Authority’s Browns Ferry Nuclear Power Plant, the temperature of Browns Ferry intake water occasionally is equal to its discharge temperature limits. Thus, the ability of the river to carry away the reactor’s waste heat is limited, necessitating a plan to bring in cold water from elsewhere.
During the California energy crisis in 2001, utilities operating Oregon and Washington’s hydroelectric dams were asked to supply California with needed electricity. Unfortunately, the Pacific Northwest region was experiencing a drought, so stream flows throughout the Columbia River basin were very low. Nevertheless, the regulators allowed more water from these reservoirs to be used for power production to help meet California’s needs. The net result: the highest number of salmon ever killed in one year in the Columbia River.
Water resources. Energy production. Climate change. Water development effects on endangered species. All of these are intertwined, and a National Research Council report suggests that federal agencies are beginning to recognize that water resources will demand more of their attention so they can better understand this ever-changing web of relationships. For years ORNL’s Milton Russell, Mike Farrell, Steve Hildebrand, and Mike Sale [leader of the Water Resources Group in the Environmental Sciences Division (ESD)] have been working to identify water resources research and development needs and to establish a water resources program to support energy research missions.
“Hydropower produces 9 to 11% of the electricity used in the United States,” says Sale. “Almost as much water (39%) is used for electricity production in the United States—that is, for power plant cooling and hydropower—as is used for irrigation and other agricultural uses (42%). You cannot produce energy without affecting water resources and aquatic ecology.”
The availability of water resources affects how much electricity can be produced; secure energy supplies depend on sure water supplies. For example, Sale notes, each time the flow of the Colorado River is reduced by 1%, the amount of power that can be produced in that river basin falls by 2.5%.
Climate change affects the amount and timing of water inflows to our reservoirs. For example, recently in the mountainous areas of the U.S. western states, there has been more rain and the snowpack has declined. “Less snowpack means less water is being stored and more water is flowing into the reservoirs as immediate runoff,” Sale says. “Existing reservoir systems are not able to use the altered flows as effectively, so less energy is produced. The solution to this problem and the salmon problem is bigger reservoirs.”
Bigger reservoirs also could provide the nation with more energy security, for example, by generating additional electricity that might be needed if nuclear power plants had to be shut down because of a terrorist attack. ORNL researchers Glenn Cada and Chuck Coutant, both in Sale’s group, are working with various partner organizations to develop new, environmentally friendly technology to reduce salmon mortality at dams; ORNL researchers are contributing computer modeling to this effort, which is funded by DOE’s Hydropower Program. “Friendlier turbines could make larger dams more acceptable environmentally,” Sale says. “Also, bigger reservoirs will provide more water for salmon, as well as for energy production.”
DOE does not have a water resources program yet, but its Office of Science is funding a three-year pilot study on the global water cycle; ORNL and four other national laboratories are participating in this study. Using internal funding, Sale and ESD’s Randy Curlee are developing a white paper on water and energy security, to help define how water resources research can become part of ORNL’s Laboratory Agenda. Sale is also completing a white paper on “Water Cycle Dynamics in the Southeast,” to identify unique regional issues. DOE is recognizing the role of water resources in securing our national energy future, but Sale and Curlee believe even more attention is needed at the national level.
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