Tennessee Valley Authority’s (TVA) massive Allen Natural Gas Plant went live Monday at 2 p.m.
The plant replaces the coal-burning Allen Fossil Plant. Both plants are located on Presidents Island. The Allen Fossil Plant was built by Memphis Light, Gas & Water in 1956 and began generating power in 1959.
TVA board members approved a budget of $975 million for the new Allen Natural Gas Plant. Though, TVA spokesman Scott Brooks said there’s not yet a final tally of plant’s actual costs.
The new plant was announced in 2014, part of a 2011 settlement with the Environmental Protection Agency (EPA) to resolve alleged Clean Air Act violations at 11 coal-fired plants in Alabama, Kentucky, and Tennessee. That agreement required TVA to invest an estimated $3 billion-$5 billion in those states at the time.
"This agreement will save lives and prevent billions of dollars in health costs,” said then-EPA Admisntrator Lisa P. Jackson. “Modernizing these plants and encouraging clean-energy innovation means better health protections and greater economic opportunities for the people living near TVA facilities.”
In Memphis, that means that natural gas now generates electricity here, instead of coal. Also, the system here is efficient, capturing heat from burned gas twice.
You may have heard the new plant called the Allen Combined Cycle Plant. Here’s what that means, according to TVA:
“The plant features a two-on-one combined cycle unit, which means that two combustion turbine generators work in conjunction with two heat-recovery steam generators and a steam turbine generator. In the first cycle, natural gas is burned to directly power two gas turbine generators that produce electricity.
The hot exhaust normally lost during this process is captured for the second cycle, where it used to boil water into steam in the heat recovery steam generators. The steam spins an additional turbine generator to produce more electricity. The steam is then condensed back to water and recycled. Water for Allen Natural Gas Plant is being provided by Memphis Light, Gas & Water.”
Methane gas from nearby Maxson Wastewater Treatment Plant is also burned at the new plant and the site features a 1 megawatt solar farm.
“Taken together, the $900 million investment will generate roughly 1,000 megawatts of power — or enough to power more than 500,000 homes and businesses in the region,” said a statement from TVA.