
Driving the Bus
System Operators Keep TVA’s Entire Power Grid in Balance
Dave Wilson hears the chime of a Priority 1 notification.
Ding, ding, ding.
He snaps his head up to look at the bank of screens above his desk.
It’s a notice from west Tennessee: Units 1 and 2 at Brownsville Combustion Turbine Plant in Haywood County are coming online.
A routine alert for this weekday morning.
But when you’re responsible for coordinating the entire electric grid for Tennessee Valley Authority, you respond to every alert like it’s highly urgent.
And every once in a while, it is.
On those occasions, Wilson and his colleagues must spring into action instantly.
It’s a bit like course-correcting at 70 mph – swerving to avoid a hazard, while keeping the vehicle on the road and all the passengers safe.
That’s why Wilson’s job has earned its nickname: Driving the bus.
Senior system operator Dave Wilson monitors TVA’s entire electrical grid from the System Operations Center in Chattanooga, Tennessee.
Six Teams
Wilson and his partner, Richard McCrory, are one of the six highly trained pairs that drive the bus at TVA.
Their official title is senior system operator for the Balancing Authority, the department in charge of making sure TVA’s electricity generation precisely matches customers’ demand for power.
All day and all night, 365 days a year.
They monitor an immense network of data from across TVA’s system that’s refreshed every 2 seconds.
Ding, ding, ding.
A new alert comes in from Hardin County, Tennessee, just above the Mississippi and Alabama state lines.
Wilson’s gaze leaps to the monitors.
Unit 3 at Pickwick Landing Dam, which has been undergoing regular maintenance, is now available to generate power for the grid.
This is just another routine notification, so Wilson softens back into his chair.
Until the next time.
Wilson and his partner keep tabs on all TVA’s generating plants, including Pickwick Landing Dam in southwest Tennessee, with six units capable of producing 260 megawatts of power.
‘You Have to Have Harmony’
TVA has more than 250 units that generate or store electricity – solar, wind, battery storage, nuclear, coal, pumped storage, gas and hydro.
Wilson and McCrory must keep tabs on all of them. At all times. They need to know which are available and which are the lowest-cost options to supply electricity to TVA’s 153 local power company partners and 60-plus large industrial customers.
As the two track the peaks and valleys of customer demand, they turn on and off roughly 7,000 to 10,000 megawatts of electricity during every 12-hour shift.
To accomplish this, Wilson and McCrory – and the five other crews – must be closely attuned to one another, said Shannon Brown, manager of the Balancing Authority.
“They coordinate everything they do right down to bathroom breaks, so there's always somebody with eyes on the system able to make split-second decisions and actions to keep the grid reliable,” she said.
It’s an intense working relationship, so Brown makes a point to match up people who get along well.
“Our operators are under constant stress,” she said. “You have to have harmony in your team for it to function right. A lot of thought goes into the pairings. I want to marry the right personality traits.”
Wilson, foreground, shares a laugh with his partner and fellow senior system operator, Richard McCrory.
Football and Lawn Care
Wilson’s partnership with McCrory is indeed a marriage of sorts.
“My wife is jealous because I spend a lot of time with him,” Wilson jokes.
To lighten the stress of the job, there’s a good deal of teasing, and college football rivalries loom large.
Wilson's team? Tennessee. McCrory's? Auburn.
The pair have also developed shared interests.
“Bermuda grass,” Wilson says.
McCrory explains: “We talk a lot about yard work. Fertilizing. Weed control. Fungus control. Insect control.”
They even went in together to buy some golf course-approved herbicide.
Working 12-hour shifts from TVA’s underground System Operations Center in Chattanooga, another stress-buster is their close community of coworkers. Often one person will pick up takeout for all 10 to 15 operators on the shift.
Fried chicken for Sunday lunch is a tradition. Wilson, like most folks, opts for a classic order: “Two-piece white.”
McCrory marches to the beat of his own drummer.
“I get picked on because I get the grilled chicken salad.”
System operators must give clearance before Gallatin Combustion Turbine Plant in middle Tennessee – or any other TVA plant – can conduct a generating test.
A Matter of Minutes
Ring, ring, ring.
An actual phone call. McCrory picks up.
A plant operator at Gallatin Combustion Turbine Plant in middle Tennessee is asking for the green light to proceed with a previously scheduled test firing of Unit 3.
McCrory gives the authorization: “Go ahead when you’re ready and let us know when you’re done.”
With coordination like this – and detailed forecasts provided by colleagues – McCrory and Wilson are able to keep everything in balance. At any given moment, they’re planning adjustments for two hours later.
Occasionally – when severe weather disrupts power generation, for example – they must adjust plans in a flash.
If the pumped storage hydro facility at Raccoon Mountain near Chattanooga has a full storage pool, it can be dispatched right away to provide the needed megawatts. Otherwise, TVA’s fastest-starting plants fire up in about 12 minutes. Either way, Wilson and McCrory must quickly assess the situation and deploy replacement generation in a matter of minutes.
These types of events aren’t common, however, and Wilson and McCrory can go a whole year without handling a single one on their watch.
Even so, they remain ever-vigilant.
McCrory, a 25-year TVA veteran, said it’s important for system operators to find ways to relax on their days off.
Ocean Sounds
It takes a special breed to manage the challenges of driving the bus, Brown said.
“Those operators are constantly anticipating, ‘What is my plan of action should that emergency situation occur?’” Brown said.
To stay sharp, each team that drives the bus spends every sixth week in training to problem-solve real-world scenarios under extreme time pressure.
Their working hours include both day and night shifts. Once in each six-week rotation, they work three day shifts then three night shifts in a seven-day span. “We call it our six-pack,” McCrory said.
The schedule takes some getting used to, and personal routines to decompress at home are important.
“You’ve got to have time for your brain to relax, for your body to relax,” said McCrory, who has a windowless spare bedroom in the basement where he can sleep undisturbed when he’s working nights.
Both men use recorded ocean sounds – or bird sounds or rainforest sounds – to help them unwind and fall asleep after a shift.
Shannon Brown, manager of the Balancing Authority, said she matches up system operators who work well together. “A lot of thought goes into the pairings.”
Neighborly Duties
When driving the bus, Wilson and McCrory’s responsibility extends beyond the edges of TVA’s service territory.
They must also monitor the tie lines that connect TVA with its 12 neighboring utilities in the Eastern Interconnection, which stretches from the Atlantic Ocean to the Rocky Mountains.
The North American power grid has been called the largest machine in the world, and it takes enormous coordination for it to operate seamlessly.
Hour by hour, the neighbors buy and sell power from each other to meet their customers’ needs and ensure the entire system converges on a stable frequency of 60 hertz.
It’s sort of like going next door to borrow a cup of sugar – at a very large scale.
“We try to help each other out,” Wilson said.
He and McCrory know their fellow operators at neighboring utilities are just like them – hyper-alert and ready to leap into action to ensure the reliability of the grid.
There’s no alternative to vigilance, said McCrory, a 25-year TVA veteran. Even with the best forecasts, you can never 100% predict the behavior of the grid.
“It’s like a living, breathing animal,” he said.
System operators turn on and off thousands of megawatts of power during every 12-hour shift. Brownsville Combustion Turbine plant in west Tennessee offers four units that can produce 425 megawatts.
PHOTO AT TOP OF PAGE: McCrory and Wilson must constantly remain on high alert, ready to take immediate action to keep the grid reliable.