VOL. 132 | NO. 40 | Friday, February 24, 2017
TVA’s Nearly $1B Natural Gas Plant 70 Percent Complete
By Bill Dries
The view is breathtaking. The Memphis skyline glints and gleams in the midday sun. The Pyramid casts its own unique light across the distance, and the Hernando DeSoto Bridge superstructure is an elegant silver set of curves to the west, filtered through bare trees. It’s a view you need a hard hat to see from the top of the massive heat recovery steam generator at the Tennessee Valley Authority’s Allen Steam Plant, under construction in southwest Memphis.
And to step out onto the northwest corner of the generator’s catwalk, you have to follow the rules – including one that dangles from a chain across the catwalk, stating “100 percent tie off beyond this point.”
The 75-acre site for TVA’s $975 million natural-gas-fired power plant is busy night and day with a crew of 750 union craft employees putting together the replacement for the nearly 60-year-old coal-fired Allen Fossil Plant on the other side of Riverport Road.
“It will be one of the most advanced, most efficient natural gas plants in the world, something we can really be proud of,” said Dan Tibbs, TVA’s project manager on the job and the general manager of major projects for the federal agency.
It doesn’t get much more major than the new plant, which will provide enough electrical power for 2 million people in 600,000 homes across southwest Tennessee, including in Shelby County.
The opening is slated for June 1, 2018, with some parts of it starting up later this year. The federal permits that allow the use of the coal-fired plant run out at the end of 2018.
The distinctive narrow smokestacks of the Allen Fossil Plant are a landmark of sorts for many Memphians, including the workers on the new project.
“When I fly into Memphis from time to time, I look over here and I know where I’m at,” said Tibbs, whose office with TVA is in Chattanooga.
At least for now the plans are to keep the old plant intact even after its retirement date.
“It won’t be demolished initially. It will be retired while we run this plant,” Tibbs said. “Once this plant proves itself and we have more information about what the world is going to look like in front of us, then we’ll make a decision.”
TVA made a momentous decision when it decided to replace the Allen Fossil Plant and its reliance on coal with a “combined cycle” plant, which uses natural gas combined with compressed air to create a controlled explosion. The energy turns the gas turbines that drive generators, creating the electricity bought by Memphis Light, Gas and Water Division – TVA’s largest customer.
On occasion, the new plant will use bio-gas as one of three environmental alternatives in the operation of the plant.
Another of the three Tibbs can’t talk about for now, as the federal agency goes through the process of getting it approved.
The third of the three measures didn’t work out. It would have used “grey water” or wastewater from the nearby city-owned Maxson Wastewater Treatment Plant to cool the natural gas plant – a plan that had been touted by the TVA board when they voted to build the new facility.
”We spent over a year engineering and looking at, I think, 13 different technologies to treat the grey water, to make it a viable solution,” Tibbs said. “But we ultimately could not design a way or engineer a way to do that without impacting the plant’s core mission.”
The mission is to provide clean and affordable energy to ratepayers, and the money ratepayers pay is what is financing the entire bill for the new plant.
The wastewater contained nutrients that TVA or someone hired by TVA would have had to treat.
Tibbs said it would have been “very expensive.”
“But more importantly it would reduce the reliability of the power plant,” he said. “It would take a lot of chemicals. It would take a lot of chlorine. It would create another solid waste stream as well. So it has its own set of environmental negatives that we had to consider.”
Instead, TVA plans to use five wells it is drilling into the Memphis aquifer to cool the new plant. The Sierra Club filed a lawsuit last month over the wells – and specifically the process of getting permits to drill them. The suit was transferred from Shelby County Chancery Court to Memphis federal court this week.
TVA could have bought the well water from MLGW but opted not to because of the expense. Nevertheless, the plant will use water it buys from MLGW as a redundant water source.
For all of the controversy, the wells are the most mundane feature on a construction site where the work is about 70 percent complete and on schedule.
Just about everything else dwarfs the well heads by height and size.
One of the two gas turbine engines is 20 times larger than a regular jet engine.
What sounds like a lot of people hammering at the same time in a specific area is a 300-ton crawler crane slowly moving into place, its enormous treads making the clacking sound heard all over the site.
A few days earlier, a 650-ton crawler crane had been working.
Nearby a group of workers were busily preparing for the arrival of the first of five massive transformers TVA bought from Mitsubishi Electric Power Products Inc. coming from the Mitsubishi plant just down the road on Riverport via another crawler crane. It’s the first purchase of its kind ever made by TVA.
“There are parts and pieces from all over the world,” Tibbs said.
The plant will be only the second in the world to use new General Electric gas turbines to convert the gas to electricity in what Tibbs said is a “leap in efficiency.”
The 7HA.02 model turbines use less water and eliminate the need to recirculate water.
Tibbs is also excited the turbines will have short serial numbers that indicate they are the fifth and sixth of their kind ever made. The first four went to power plants in Texas.
For now, the staging for the construction work takes up all 75 acres. Once the construction is done, the plant itself will take up 30 acres with room for expansion and additions.
The construction job is an $89 million payroll and there are a lot of different jobs going on simultaneously on the ground and various levels above ground.
“Nobody Gets Hurt” was the slogan on the back of one worker’s hard hat. There are “rules of the deck” posted on some of the trailers used for worker supplies. Steel Jobox compartments function as desks shielded from the wind and rain. They are strewn with plans that workers gather around.
Tibbs found a place to park, telling another worker, “I don’t want to get in your way.”
“If you do, we’ll let you know,” the worker replied.