Raccoon Mountain Pumped-Storage Plant
Encyclopedia
Raccoon Mountain Pumped-Storage Plant is a pumped-storage
hydroelectric
underground
power station
in Marion County
, just west of Chattanooga
in the U.S. state
of Tennessee
.
The facility is owned and operated by the Tennessee Valley Authority
(TVA). Construction was started in 1970 and was completed in 1978.
Water is pumped from Nickajack Reservoir
on the Tennessee River
at the base of Raccoon Mountain to a storage reservoir
built at the top of the mountain. The reservoir at the top of the mountain covers 528 acres (213.7 ha), with a dam
that is 230 feet (70.1 m) high and 5800 feet (1,767.8 m) long, the largest rock-fill dam ever built by TVA. It takes 28 hours to fill the upper reservoir. During periods of high electric demand, water can be released from the reservoir through a tunnel
drilled through the center of the mountain, driving electric generators in an underground hydroelectric plant. The plant has a capacity of 1600 megawatts of electricity and can generate for up to 22 hours. The plant is used most every day and serves as an important grid balancing in the TVA system.
Pumped-storage hydroelectricity
Pumped-storage hydroelectricity is a type of hydroelectric power generation used by some power plants for load balancing. The method stores energy in the form of water, pumped from a lower elevation reservoir to a higher elevation. Low-cost off-peak electric power is used to run the pumps...
hydroelectric
Hydroelectricity
Hydroelectricity is the term referring to electricity generated by hydropower; the production of electrical power through the use of the gravitational force of falling or flowing water. It is the most widely used form of renewable energy...
underground
Underground power station
An underground power station is a type of hydroelectric power station constructed by excavating the major components from rock, rather than the more common surface-based construction methods....
power station
Power station
A power station is an industrial facility for the generation of electric energy....
in Marion County
Marion County, Tennessee
Marion County is a county located in the U.S. state of Tennessee. As of 2000, the population was 27,776. Its county seat is Jasper.Marion County is part of the Chattanooga, TN–GA Metropolitan Statistical Area.-Geography:According to the U.S...
, just west of Chattanooga
Chattanooga, Tennessee
Chattanooga is the fourth-largest city in the US state of Tennessee , with a population of 169,887. It is the seat of Hamilton County...
in the U.S. state
U.S. state
A U.S. state is any one of the 50 federated states of the United States of America that share sovereignty with the federal government. Because of this shared sovereignty, an American is a citizen both of the federal entity and of his or her state of domicile. Four states use the official title of...
of Tennessee
Tennessee
Tennessee is a U.S. state located in the Southeastern United States. It has a population of 6,346,105, making it the nation's 17th-largest state by population, and covers , making it the 36th-largest by total land area...
.
The facility is owned and operated by the Tennessee Valley Authority
Tennessee Valley Authority
The Tennessee Valley Authority is a federally owned corporation in the United States created by congressional charter in May 1933 to provide navigation, flood control, electricity generation, fertilizer manufacturing, and economic development in the Tennessee Valley, a region particularly affected...
(TVA). Construction was started in 1970 and was completed in 1978.
Water is pumped from Nickajack Reservoir
Nickajack Lake
Nickajack Lake is the reservoir created by Nickajack Dam as part of the Tennessee Valley Authority. The lake stretches from Nickajack Dam to Chickamauga Dam, and runs along the shores of Chattanooga, TN...
on the Tennessee River
Tennessee River
The Tennessee River is the largest tributary of the Ohio River. It is approximately 652 miles long and is located in the southeastern United States in the Tennessee Valley. The river was once popularly known as the Cherokee River, among other names...
at the base of Raccoon Mountain to a storage reservoir
Reservoir
A reservoir , artificial lake or dam is used to store water.Reservoirs may be created in river valleys by the construction of a dam or may be built by excavation in the ground or by conventional construction techniques such as brickwork or cast concrete.The term reservoir may also be used to...
built at the top of the mountain. The reservoir at the top of the mountain covers 528 acres (213.7 ha), with a dam
Dam
A dam is a barrier that impounds water or underground streams. Dams generally serve the primary purpose of retaining water, while other structures such as floodgates or levees are used to manage or prevent water flow into specific land regions. Hydropower and pumped-storage hydroelectricity are...
that is 230 feet (70.1 m) high and 5800 feet (1,767.8 m) long, the largest rock-fill dam ever built by TVA. It takes 28 hours to fill the upper reservoir. During periods of high electric demand, water can be released from the reservoir through a tunnel
Tunnel
A tunnel is an underground passageway, completely enclosed except for openings for egress, commonly at each end.A tunnel may be for foot or vehicular road traffic, for rail traffic, or for a canal. Some tunnels are aqueducts to supply water for consumption or for hydroelectric stations or are sewers...
drilled through the center of the mountain, driving electric generators in an underground hydroelectric plant. The plant has a capacity of 1600 megawatts of electricity and can generate for up to 22 hours. The plant is used most every day and serves as an important grid balancing in the TVA system.