TVA has started raising the lake levels at Boone Lake after the drawdown for repairs at the dam. TVA says it has to generate more electricity at Boone because of the demand from the harsh winter. (Lee Talbert/Johnson City Press)
With another cold snap expected tonight into Friday morning, the Tennessee Valley Authority has halted all non-emergency maintenance at its generation and transmission facilities — including Boone Dam — to reduce the risk to the valley’s power supply, agency spokesman Travis Brickey said Wednesday.
“We’re under a conservative operation alert, which means we’re curtailing any maintenance activities that could cause the risk that we would not be able to operate that facility,” Brickey said. “Part of the project at Boone is replacing the chains that control the head gate. The head gate must be open to let water into the penstock to allow the blades to turn the turbine and run the generator.
“If for some reason there was an accident or something happened while they were working on those chains so that we couldn’t open the head gate, then we couldn’t generate electricity at that unit.”
When temperatures drop into the single digits today, the provider will need the dam’s 89 megawatts of generating capacity to help meet the electricity demands of the 9 million homes served by the TVA in the Southeast.
On Jan. 7, when temperatures approached 0 degrees, the TVA system reached a morning peak demand of 32,490 megawatts, its second-highest recorded winter demand, triggering a call for customers systemwide to conserve electricity where possible to avoid possible brownouts.
Today, forecasters expect a high of 19 early in the morning, and a gradual drop of temperatures to 6 degrees during the night.
Friday should see a high of approximately 26 degrees and a nighttime low of 12 degrees.
As the thermometer dips again, the agency is expecting another spike in usage, possibly as high as the peak two weeks ago.
Once the weather begins to warm up again, which according to National Weather Service meteorologists could be Saturday, the TVA will consider lifting the maintenance moratorium, Brickey said, allowing work to resume at Boone Dam.
“This will not put the project behind schedule, these kind of things are built into the schedules for projects like this,” Brickey said to dispel any fears the work may not be finished in time to refill the lake for summer recreation season. The guys doing the work are confident it will not put us behind.”
The 60-year maintenance also called for the replacement of the dam’s spillway cables, which was completed Friday.
To more easily access the cables, TVA lowered the lake 14 feet below its normal winter level, and has now begun the process of letting it refill.
Brickey said the water can rise another 9 feet, to about 1,358 feet above sea level, and still allow workers to reach the heavy chains for the next phase of the project.
Once the work is finished, TVA will allow the reservoir to slowly refill, depending on the amount of rainfall and water runoff, aiming to have it back to normal levels by May.