Ackerman Ramps up Efficiency, Winterization
TVA’s Largest Gas Plant Improvement Nears Completion
On a typical day at Ackerman Combined Cycle Plant in Mississippi, a crew of about 20 employees keeps this 705-megawatt site ready to supply power to more than 400,000 homes.
But this past October, things started looking a little different.
This fall, Ackerman underwent the largest maintenance outage ever conducted at a TVA gas plant.
This included a major gas turbine rebuild, a major steam turbine rebuild, a steam turbine rotor refurbishment, three generator inspections and a complete demolition and replacement of the 12-cell cooling tower.
“This work will make these units more reliable and efficient,” Jason Jones, TVA outage manager, said. “We coordinated essentially three different major efforts into one single outage, including activities to improve winterization of the site. This will better enable us to serve the 10 million people of the Tennessee Valley region.”
Expand to Improve
To pull off this outage, the population at the site ballooned to almost 300 employees at its peak.
“It took months of planning to set up the complex logistics of this outage,” Ryan Rodewald, senior project manager, said.
More than 15 contract partners worked on the steam turbine alone, according to Lee Wright, outage manager.
“To put this in perspective, typically we do a gas turbine outage every five years and a steam turbine outage every 10 years. This outage just so happened to sync up where the gas turbines and the steam turbine were planned to be refurbished at the same time,” Wright said.
To accommodate the incoming workforce, the outage team had to build a new parking lot, set up trailers for offices and be extra vigilant to account for safety.
“We had to think about the flow of traffic, the space needed to store incoming and outgoing materials, and the equipment needed to pull off not one but multiple outages at once,” Jones said. “Think two of everything – two 600-ton cranes, two 285-ton cranes and triple the amount of people. All in the same small footprint.”
The team also had to think about space for breakrooms and where to go in case of a storm.
“With the amount of work, we had to take extra precautions for safety,” Tyler Ray, outage manager, said. “For example, we implemented a spotter requirement at all times for any equipment usage to ensure no one was inadvertently impacted by all the moving parts and additional personnel onsite.”
A spotter keeps watch to ensure moving equipment doesn’t come in contact with any crew or equipment at the site.
With separate teams onsite for various jobs, nearly 100 contractors focused solely on winterization efforts, such as upgrading heat trace technology to keep instrumentation from freezing, as well as building enclosures and installing insulation to keep systems cozy and operational during inclement weather.
While employees worked to keep components warm from outside freezing temperatures, a separate onsite team ensured water systems stayed cool.
TVA invested nearly $10 million to demolish and rebuild the 12-cell cooling tower that manages the cooling water for the three-unit site.
Cooling towers are critical to the health of the plant because they circulate all plant water to keep components and systems cool during operation.
“This cooling tower – about the length of two football fields – was originally built out of wood. But upon replacement, we upgraded the material to a fiberglass reinforced polymer,” Rodewald said. “This rebuild will improve performance and durability.”
“A cooling tower is a tough environment,” Ray said. “There’s heat, chemicals and constant flow of water, and after 20 years, the existing tower reached its end of life and needed to be replaced. The new cooling tower will supply water at the site for the next 20-plus years.”
“I’m proud at what this team has accomplished,” Clay Mullins, senior manager of Regional Gas Ops, said. “The coordination, collaboration and teamwork across multiple business units, stakeholders and vendors was truly an impressive accomplishment. I’m grateful to everyone who put their all into keeping Ackerman in tip-top shape to continue serving the Valley.”
Learn more about TVA’s generating plants at the Our Power System page.