At the entrance to TVA’s Raccoon Mountain Pumped Storage Facility is a most-unusual artifact: a turbine rotor that was retired during the course of routine maintenance. This device has a unique technical requirement: it must serve both as a turbine rotor and as a pump. Stop and admire the engineering, and pick up a quick smiley ! In compliance with TVA guidelines, this non-magnetic cache is not in contact with the artifact …
Raccoon Mountain, completed in 1978, serves as a massive hydraulic storage-battery for the TVA system, storing electrical power that has been generated during periods of low demand for use in high demand. Water is pumped from the Tennessee River to a 528-acre reservoir (107 billion gallons) at the top of the mountain, held back by the largest rock-fill dam ever built by TVA. Then, whenever needed, the water is released back through the same penstocks, through the same pumps, which now act as electrical generators. These can contribute up to 1,652 megawatts of electrical power to the TVA system for up to 22 hours … at no further cost. And, since it can switch from one duty to another at a moment’s notice, it serves an important function for peak power generation and grid balancing throughout the TVA system.
Socially speaking, the Raccoon Mountain Facility is perhaps TVA’s “most entertaining” property, with interesting technology, stunning views from the top of the mountain in various directions, miles of mountain-biking (and hiking, no horses …) trails, and – did we mention it? – many other geocaches. It is truly unique because it reaches from the river’s edge to the very top.