An overall wet year has led to record-breaking numbers for Tennessee Valley Authority officials and the 29 hydroelectric dams positioned along the Tennessee River system.
TVA reports more power was generated through hydroelectricity in fiscal year 2013, ending Sept. 30, than any other time in the company's 80-year history.
The dams were able to provide 18.5 million megawatt-hours of energy, which surpasses the previous record set 40 years ago. TVA generated 122,000 megawatt-hours of hydroelectricity in 1973. The 18.5 million megawatt-hours of energy can provide more than 1.2 million households enough power for an entire year.
Travis Brickey, spokesperson for TVA, said Fort Loudoun Dam produced 879,411 megawatt-hours through the fiscal year. Melton Hill Dam produced 196,734 megawatt-hours. Tellico Dam is not a hydroelectric facility, so no power is generated there.
"We had heavy amounts of rain," Brickey said. "We had a lot of rain consistently throughout the year when we typically will get most of our rain and runoff in the winter and early spring, and then, of course, it dries up over the summer, but we didn't see that this year. We had a wet summer, a really wet July and so we were able to take advantage of all that extra water."
Brickey said TVA noticed a "consistent" pattern of rainfall throughout the year. Increased rainfall led to an increase in runoff. TVA received nearly 62 inches of rainfall and 30 inches of runoff this fiscal year, which were "121 percent and 136 percent of normal, respectively."
Water runoff is rainfall that eventually flows into the Tennessee River, TVA's dams and tributaries.
"Down here if we're hearing, 'Well, the mountains of Tennessee and North Carolina and Virginia got a lot of rain, like in the Boone, N.C., area and the Tri-Cities," Brickey said, "well, eventually that water has to flow past Lenoir City, and we had got a tremendous amount of rain and there was really some high spots in the July event up in the mountains above Watauga Reservoir that really caused that reservoir to spike twice, once in May and once in July."
Those two spikes at the Watauga Reservoir broke two water elevation records. Of the various energy sources, hydroelectricity is the cheapest to produce, Brickey said. TVA does not use hydropower as often because it has a "limited capacity number."
"If all the turbines were running and generating electricity, hydropower is about 3,500 megawatts, and I mean like just right now is almost 18,000 megawatts," Brickey said. "So that's how much energy is being demanded on the TVA system because you can't store electricity. You have to supply the instant that it's demanded to you."
TVA's 29 dams only produce about 10 percent of total energy per year, but the weather helped contribute an additional 3 percent, John McCormick, senior vice president for TVA's River Operations, said. The extended period of rainfall this year has helped TVA operations avoid nearly $800 million in flood damages in January, along with an added $48 million in July, he said.
In August, the TVA board of directors approved $350 million for modernizing 51 hydro-generating units. Updates should increase unit capacity by 184 megawatts.
Of the four turbines Fort Loudoun uses, units 3 and 4 have been hydromodernized, Brickey said. Both of Melton Hill's turbines still require improvements.