More electricity was generated from the Tennessee Valley Authority’s 29 hydroelectric dams in fiscal year 2013, which ended Sept. 30, than any year in the agency’s 80-year history.
The dams provided 18.5 million megawatt-hours of clean, renewable energy, breaking the previous record set in 1973 by 122,000 MWh. That is enough electricity to serve more than 1.2 million homes in the TVA service area for an entire year.
Above-average rain and runoff fueled the increase in hydro generation. The Tennessee Valley received almost 62 inches of rainfall and almost 30 inches of runoff in fiscal 2013, which were 121 percent and 136 percent of normal, respectively. Runoff is the amount of rainfall that actually reaches streams and creeks, and eventually the Tennessee River, its tributaries and TVA’s dams.
“This is a credit to all the hard working TVA employees who manage our integrated river system around the clock, everyday of the year,” said Chip Pardee, TVA executive vice president and chief generation officer. “This includes the professionals at the dams, in our river forecast and power dispatch centers, and the rest of our transmission and operations groups. Together they have maximized low-cost hydro generation for the 9 million power consumers in TVA’s power service area.”
“It has been a wet year and our River Operations team took advantage of it. We were able to generate electricity from the dams in months when we typically are trying to hold on to water, like July for recreation and stewardship purposes,” John McCormick, TVA vice president, River Operations said. “As our cheapest energy source, all this hydro generation has helped lower our fuel cost to customers.”
While some of TVA’s dams are as old as the agency, TVA has continued to upgrade and modernize their components. Since 1992, TVA has upgraded 55 of its 109 conventional hydro generating units, gaining 442 megawatts of capacity for the system. In August, the TVA board of directors approved $350 million for additional hydro modernizations to 51 units that will increase their capacity by 184 megawatts.
“In a typical year, conventional hydroelectric power makes up about eight to 10 percent of TVA’s total electricity production, with the bulk of our generation coming from nuclear, coal and natural gas. But In fiscal 2013 hydroelectric power contributed about 13 percent of the generation mix,” Mr. McCormick said. “More importantly, TVA was able to reduce flooding impacts during large rain events throughout the year. In January, TVA’s operations averted about $800 million in flood damages and an additional $48 million in July."
During an average year, TVA’s reservoir operations avert approximately $250 million in flood damage. TVA estimates it has averted nearly $7 billion in flood damage since it completed its first dam, Norris Dam, in 1936.