Nearly a decade after TVA shut down its Widow's Creek Fossil Plant near Bridgeport and abandoned construction of the unfinished Bellefonte nuclear plant in Hollywood, the federal utility is looking at building a different type of power plant in Jackson County, Alabama.
The Tennessee Valley Authority has begun a study on whether to build a pumped storage power plant at either of two mountain ridges along the Tennessee River in Northeast Alabama.
The proposed hydroelectric storage facility would be similar to the Raccoon Mountain pumped storage facility built by TVA just west of Chattanooga in the 1970s. If the project proves feasible, TVA projects the new pumped storage plant would cost from $2 billion to $4 billion to construct and create about 1,000 temporary construction jobs and 60 permanent facility jobs.
As a type of giant storage battery for TVA, the pumped storage plant could be critical in helping TVA store power generated by the sun or wind and delivering the power when needed most, especially when renewable power sources are not available.
TVA is considering building a 1,600-megawatt pumped storage plant in Northeast Alabama at either the former Widows Creek coal plant near Stevenson, Alabama, or at Rorex Creek near Pisgah, Alabama.
TVA conducted preliminary studies for a power station in the Pisgah area in the 1970s and again in the 2000s, but Jackson County officials said they hope TVA moves ahead with such plans this time.
Jackson County Commission Chairman Bill Nance said commissioners "are pleased that the Tennessee Valley Authority is considering two sites in Jackson County for a potential pumped storage hydro facility." Nance said such a project "will have a positive impact on our county's economic development and growth" with new jobs and more tax-equivalent payments in Jackson County.
"Also, we expect TVA's pump storage facility will help with local infrastructure improvements and provide recreational opportunities open to our citizens such as hiking and biking trails, camping and picnic areas, habitat improvements and improved river access," Nance said in an emailed statement. "We look forward to the study's completion and believe Jackson County offers a great location."
HYDRO POWER STORAGE
Pumped storage hydro facilities work like a giant storage battery. Water is pumped from a lower reservoir to one uphill at night or during periods of surplus electricity generation, when power prices typically drop. During peak demand periods, usually in morning or afternoon hours when prices rise, gates open to send the water back downhill to the lower reservoir, engaging turbines to create energy.
Such storage capacity is expected to be more in demand as distributed energy generated from solar and wind turbines increases over time, producing surplus power when the sun shines and the wind blows and less power when such renewable energy is not available.
In the Tennessee Valley, the only existing pumped storage facility is atop Raccoon Mountain just west of Chattanooga, which was completed in 1978 at a cost of $310 million. The Raccoon Mountain facility includes a 523-acre lake atop the mountain capable of storing 107 billion gallons of water. Its four generating units can produce up to 1,652 megawatts of power when in full operation, or nearly as much power as the Sequoyah Nuclear Power Plant, for short periods.
TVA had to shut down Raccoon Mountain from 2012 to 2014 to make nearly $90 million in repairs of a design flaw that cracked some of the rotors in the hydroelectric station. But over the past decade, Raccoon Mountain has helped TVA balance its generation with varying load demands.
The upper reservoir, located at the top of Raccoon Mountain, contains approximately 107 billion gallons of water covering 528 acres of water surface, drawn from the adjacent Tennessee River.
TVA is also studying the possibility of expanding the power output at the Raccoon Mountain pumped storage facility rather than building a new plant in Jackson County. TVA officials say detailed planning for the project is expected to take about three years and a specific location for the facility hasn't been determined.
"If we move forward, we would want to have one of the pumped storage facility options completed in the 2030s time frame," TVA spokesman Scott Brooks said in a telephone interview. "This is the first step in the process."
OTHERS PURSUE PUMPED STORAGE
Just to the south, Alabama Power Co. is also considering building a pumped storage facility in Northeast Alabama in Etowah County.
The Federal Energy Regulatory Commission issued a preliminary permit last year to Alabama Power Co. to study the 1,600-megawatt Chandler Mountain Pumped Storage Project. The facility would be located on Little Canoe, Gulf and Jake creeks near Steele in Etowah and St. Clair counties.
Four years ago, a private developer of pumped storage plants -- Renewable Energy Aggregators in Doylestown, Pennsylvania -- proposed building a 80-megawatt pumped storage facility on Sand Mountain near where Tennessee, Georgia and Alabama intersect. But that project never moved forward.
The National Hydroelectric Association reported pumped storage hydropower provides the vast majority of the nation's energy storage, with over 22,000 megawatts of installed capacity.
"However, the industry is primed to do more with thousands of megawatts of proposed projects across the country, particularly in the West," the industry trade group said in a recent report.
Raccoon Mountain and the Jackson County sites being considered each offer a natural mountain next to a major water source and are relatively close to major transmission lines TVA has already erected in the area.
For the pumped storage hydro facility to be built, the site for the upper reservoir would need to be cleared on the selected mountain ridge. At the Raccoon Mountain pumped storage plant, part of the mountain also was hollowed out for water to be pumped up to the higher lake and for generators to produce electricity at the bottom of the mountain.
TVA's construction of Raccoon Mountain displaced some 10 million cubic yards of earth to build the reservoir, and 12,000 feet of subterranean tunnels were constructed. The plant's central hall is described by TVA as being "a space the size of a football field (carved) out of solid limestone."
The disruption needed for such a facility led to environmental opposition three decades ago when TVA considered another site in Sequatchie Valley for a pumped storage facility. Environmental leaders said energy storage is key to balancing variable renewable generation, but any new project needs to also consider the effect on natural areas that would be disturbed.
"We support storage because it gives the utility greater flexibility overall for operations and for working with renewable resources," Stephen Smith, director of the Southern Alliance for Clean Energy, said in a telephone interview Tuesday. "But it has to be done in an environmentally responsible way. You don't want to be damaging or flooding large natural areas which are under pressure already."
In its notice of intent about the project, TVA is soliciting public comments as it begins its environmental assessment of the alternative sites.
TVA will also hold a virtual public meeting at 6 p.m. June 22 and public comments will be accepted for the initial study of the three potential pumped storage facility sites through July 5. Comments can be submitted online or by emailing [email protected].