TVA Raccoon Mountain: Generating Power Hundreds of Feet beneath Your Feet

Описание: A huge construction projectis happening in our backyard, but you can't see it.
The massive construction project is hundreds of feet underground and when it's finished, you'll have extra power to keep warm this winter.
Many people know about the man-made lake on top of Raccoon Mountain west of Chattanooga. It's the Pumped Storage Plant underground that's having work done.
How does it work? It's really simple. Millions of gallons of water are taken out of the Tennessee River every night, through a pipe that brings it 400 feet into the base of Raccoon Mountain. From there, it then goes into a pump that sends it 400 more feet, then up almost 1,100 feet to a man-made lake on top of the mountain.
During the day, that same water is released through the same pipe back down the mountain to the same pumps that sent it skyward, only this time they are serving as generators with turbines inside, that the water turns to generate electricity.
That same water is then released back into the Tennessee River.
Ever since 1978, Raccoon Mountain has been one of the little-known ways that T-V-A generates power. "It's still a mystery to some people," says plant manager Ken Cornett. "It's an unknown and it's really an engineering marvel when you see how it operates."
Every five to seven years, TVA says it has to shut down the four generators at the Raccoon Mountain Pumped Storage Plant for maintenance. "We're looking for cracked concrete, excessive wear that we can take the opportunity to repair or correct," says Raccoon Mountain Senior Operator Heath Rogers.
During the shutdown period, usually one of the four big water cylinders, called spherical valves are completely taken out, and the seals on them replaced. The spherical valve works like a water faucet in the kitchen. The seals being replaced are like the rubber gaskets in the faucet. "It's critical for TVA to be able to continue running the other 3 units in the event that a maintenance issue arises with any one of them," Rogers says.
At one point, TVA says it had problems with rotors in the power generators that spin to make electricity during the day. "Over the past three years, we've done a lot of work to replace the rotors, we've rebuilt equipment on the generators," says Cornett, "we've put new transformers in the mountain and the cables are the last piece of the puzzle."
Those cables carrying electricity generated from beloware massive. "Each one weighs 15 pounds per foot and they range anywhere from 2,200 feet to 2,600 feet," Cornett says, "so you're looking at approximately 40,000 pounds per cable."
Each cable is pulled up the visitors center elevator shaft 1,080 feet high, to be tied into the TVA power grid. While work is going on down below, work on other parts of the facility is also going on.. almost 1,100 feet higher, workers are doing maintenance on the lake.
We're told that no major problems were discovered during this down time for Raccoon Mountain.
Right now, the Raccoon Mountain Pumped Storage facility is on target to resume generating power on November 21st.
By Calvin Sneed