Memphis’ air benefits as TVA Allen plant closes
A.C. Cox used to dread coming to work when it rained, especially during downpours so heavy that wet coal would clog the pipes feeding the roaring cyclone furnace at the Allen Fossil Plant.
“Wet coal meant trouble for everyone,” recalls Cox, 85, who began working at the plant just after its completion in 1959.
More than a quarter-century after he retired, Cox returned to the Tennessee Valley Authority facility in Southwest Memphis a few weeks ago. He leaned over the control panel he helped operate for so many years and turned a familiar switch.
With that simple act - disconnecting the electrical generating units from the TVA grid - a power plant that had kept the lights on in Memphis ever since the days of rotary phones and cars with tailfins was retired.
In a very literal sense, the shutdown of a plant that burned 7,200 tons of coal daily should help Memphis-area residents breathe easier. The Allen plant was by far the largest single source of air pollution in Shelby County, with its 400-foot-tall stacks spewing more than 11,000 tons of sulfur dioxide, 2,600 tons of nitrogen oxides and the equivalent of 5.4 million tons of carbon dioxide annually.
Carbon dioxide emissions contribute to climate change, scientists say, while sulfur dioxide is blamed for acid rain. Nitrogen oxides react with volatile organic compounds to create ozone, a component of smog.
The facility also released toxic lead and mercury at annual rates of about 90 and 110 pounds, respectively.
Plant’s emissions had been reduced
As bad as the plant’s pollution has been in recent years, it used to be a lot worse. In past decades, before electrostatic precipitators were installed and prior to the switch to cleanerburning low-sulfur coal, Allen was discharging more than 100,000 tons
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of sulfur dioxide and 40,000 tons of nitrogen oxides each year.
“In the morning you could see a plume of ash and stuff on the horizon,” Cox recalls.
The 59-year plant on the shore of McKellar Lake was taken offline as TVA prepares to begin operating the $975 million Allen Combined Cycle Plant barely a quartermile to the south on Riverport Road.
When it begins producing power in the next month or so, the highly efficient natural gaspower facility will emit only about 1 percent of the sulfur dioxide that the coal facility discharged while slashing nitrogenoxide and carbon dioxide releases by about 80 percent and 37 percent, respectively.
The pollution decline resulting from the coalfired plant’s retirement should have “a direct impact on the health and well-being” of Shelby County residents, said Tyler Zerwekh, administrator of environmental health for the Health Department.
“That means reduced cases of asthma, reduced instances of irritation, and hopefully we’ll have reduced emergency room visits and doctors visits,” Zerwekh said.
Alleged Clean Air Act violations involved
The transition to the the gas plant culminates a process that began in 2011, when TVA entered into agreements with state and federal regulators, as well as environmental groups, settling alleged Clean Air Act violations at Allen and other coal-fired facilities.
The agreements required TVA to either retire the coal plants or equip them with even more costly pollution-control equipment by December 2018.
Environmentalists have hailed the agency’s decision to retire Allen, even though they would have preferred a renewable-energy facility replace it.
“We’ve been big supporters of TVA moving away from coal,” said Stephen Smith, executive director of the Southern Alliance for Clean Energy. “I think that (coal) technology needs to be greatly reduced and phased out.”
But while eliminating large amounts of air pollution, the retirement of the fossil plant still leaves some environmental messes, including a large coal-ash pond on the east side of the facility.
Two options for dealing with hazards from the pond include closure-inplace, which would involve sealing the coal ash, and closure by removal.
The choice of closure options could hinge on recent investigations that uncovered extremely high levels of arsenic, as well as elevated concentrations of fluoride and lead, in shallow ground water near the pond. TVA is working with the Tennessee Department of Environment and Conservation to conduct a more comprehensive study of the contamination.
Recent environmental research determined there was a connection between the contaminated shallow aquifer and the deeper Memphis Sand aquifer - the source of public drinking water in the area.
In response to the contamination threat, TVA has put on hold plans to pump an average of 3.5 million gallons of water daily from the Memphis Sand to cool the new gasfired plant.
Instead, the agency will purchase cooling water from the Memphis Light, Gas and Water Division for at least the time being.
Salvage, demolition are next
As the environmental studies continue, TVA is readying the plant for eventually salvage and demolition.
Originally built by the Memphis Light, Gas and Water Division and later purchased by TVA, the plant at one time could generate about 900 megawatts, although its summer net capacity in recent years was 702 megawatts.
The new plant is called a combined-cycle facility, meaning it will have combustion turbines generating power as they spin, but there also will be additional electricity produced from the hot exhaust gases.
The plant will produce more than 1,000 megawatts, enough electricity for 580,000 homes, according to TVA.
A lot of the equipment at the old plant is expected to be sold for use at other generating facilities.
During a recent tour into the bowels of the coal-fired plant, technical support manager James Evans pointed to valves and other components.
“There are power plants all over the world that can use this stuff,” Evans said.
Once the plant has been cleaned up and stripped of reusable equipment, it will be torn down. But it won’t happen quickly.
“In most cases, we take the building down piece by piece,” TVA spokesman Scott Brooks said.
Local economic-development officials have expressed interest in the site as a prospective location for new industry.
For Cox, the closure elicits mixed emotions. He understands that given its age, condition and pollution problems, the plant must be retired.
But the facility where he rose through the ranks from plant helper, or laborer, to shift supervisor over a nearly 32-year period still lives in his thoughts and dreams.
“Whenever I wake up in the middle of the night, this steam plant would be on my mind,” Cox said.
Reach Tom Charlier at thomas.charlier@com
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