Raccoon Mountain Refill

With maintenance work on its pumped-storage plant complete, 107+ billion gallons of water are pumped from the Tennessee River back into the mountaintop reservoir. You have to see it to believe it.

NOVEMBER 2016—When it’s full, TVA’s Raccoon Mountain Reservoir is like having money in the bank. At a moment’s notice, the hydropower plant has the potential to drain water away from the reservoir at the top of the mountain, down a 1,080 shaft, and be generating 1,600 megawatts of electricity—or enough to power 935,000 homes. So often, it is a key player in balancing system load during times of peak demand.

However, the reservoir was drained completely in October for routine repair and maintenance work, during which time two of the great spherical valves that act as stoppers to keep the water at the top of the mountain—or let it go—were replaced.

With work complete, the reservoir was refilled over the course of five days in late November, when the plant’s powerful Voith pump turbines moved more than 107 billion gallons of water from the Tennessee River back to the top of Raccoon Mountain to ready the facility for normal operations.

Here, our time-lapse video shows the four-day process, which won't be repeated again for another seven years.