TENNESSEE VALLEY-How do you know summer has arrived?
Memorial Day weekend? The last day of school? The first evening you see a firefly?
For the Tennessee Valley Authority, it arrives with the completion of spring outage season.
That’s when TVA’s equipment and facilities – and its employees and partners – prepare to tackle whatever Mother Nature might dish out during the hot months.
“We’ve just finished a very successful outage season,” said Shannon Brown, manager of TVA’s Balancing Authority, which coordinates operations of the electrical grid.
This planned spring outage work, focused on maintenance across TVA’s generation fleet, is like a massive version of something everyone can relate to.
“You have regularly scheduled maintenance you need to do on your vehicle so it doesn’t leave you on the side of the road, right? Things like your oil changes, tire rotations and filter changes? It’s much the same for our generation facilities,” Brown said.
Teams at generating facilities around the Valley region perform routine maintenance during spring outages, when power demand is lower.
“Every piece of TVA has their own summer readiness plan,” Brown said. “Whether you’re a hydro facility or a nuclear facility or a gas facility, they all have a set of criteria to make sure those facilities are summer-ready.”
She highlighted the many TVA teams that have a hand in these preparations.
“By the time late May, early June rolls around, these facilities are ready to go – basically like servicing your vehicle before a long road trip.”
The same goes for TVA’s transmission network, which uses spring outage season for maintenance and repairs on transmission lines, transformers and the capacitor banks that regulate voltage.
“All of the things that allow us to better transmit power most efficiently and reliably to the customers,” Josh Shultz, TVA’s general manager of transmission operations, said.
“We work very hard to button up the system,” Shultz said. “We make sure everything’s back to normal so you have the most reliable transmission system you can get.”
Heat and Humidity
Summertime brings a unique set of challenges in managing the load, which is the total demand for electricity on TVA’s system.
High temperatures can tax TVA’s generating fleet and infrastructure.
“For the summer months, of course, the No. 1 thing we’re monitoring is heat and high temperatures,” said Nick Austin, a meteorologist who works as a TVA senior short-term load planning specialist.
“The hottest temperatures are typically in July and August. If we’re expecting a heat wave – where we’re going to see temperatures well above normal for at least two or three days – that’s going to have a much higher impact on the load, because each day the stress on the load is a little higher. It’s kind of a gradual build.”
High humidity also drives up demand, Austin said.
That’s partly because the moist air makes air conditioners work harder, but mostly it’s about comfort.
“The heat index, which is temperature and humidity combined, will make it feel a little hotter than it actually is,” he said.
Demand Peaks
Demand typically rises throughout a summer day, peaking around 5 p.m. CT.
While TVA’s nuclear and coal plants generate round-the-clock baseload power, combined cycle natural gas plants can ramp up generation during peak times.
When power is needed quickly, TVA dispatches hydroelectric units at its dams, fast-starting gas combustion turbines and Raccoon Mountain Pumped Storage Plant.
The new battery storage facility TVA is bringing online in Vonore, Tennessee, will also help meet peaks.
But storms can pop up suddenly, cooling things off or changing the timing of the demand peak. Matching generation capacity to customer demand is what it’s all about – and that’s a minute-by-minute job.
“You’ve got to be prepared for the swings, and that’s really the challenge,” Gary Mazo, TVA’s vice president of fuels, said. “Even over a weekend, the load can change so much. The challenge is when the load is either a lot higher or lower than we’re expecting.”
On a 100-degree day, TVA needs 50% to 60% more natural gas and coal than on an 80-degree day, Mazo said.
Part of his group’s summer readiness has involved continued diversification of fuel sourcing, ensuring plants have fuel when they need it.
“Our goal is to provide a resilient, flexible fuel supply that allows our generating fleet to run reliably,” Mazo said.
‘Staffed and Ready’
Preparedness is not just about things. TVA’s people play an enormous role.
“We pay close attention to our staffing to make sure that we’re staffed and ready, and that we have extra staff available should we need extra hands,” Brown said.
TVA conducts drills on emergency protocols with its 153 local power company partners and the industrial customers it serves directly.
“We do that to make sure everyone’s on the same page,” Brown said.
Emergency protocols go into effect if it gets hot enough based on the average temperature in the five major metropolitan areas – Memphis, Nashville, Knoxville and Chattanooga in Tennessee and Huntsville, Alabama.
“If it hits 96 degrees, we’re going to start up our Emergency Operations Center and start communicating early and often,” Shultz said.
With customers. With emergency management agencies in the seven states TVA serves. And with the general public.
It’s “an all-hands-on-deck team effort,” Mazo said.
Everyone Can Help
The best way for people to help reduce peak demand is to participate in efficiency programs, said Monika Beckner, vice president for TVA’s EnergyRight, which offers a wide range of services for homeowners, renters and businesses.
TVA offers cash rebates to homeowners who upgrade their HVAC systems, add insulation or seal air leaks, among other items. Businesses can receive up to $3 million per year in incentives for energy upgrades.
Through TVA’s Demand Response programs, businesses can also sign up to receive financial credits by agreeing to limit their power usage in certain high-demand situations.
“Every time we adjust our thermostat, unplug devices or make energy-saving upgrades, we’re actively reducing strain on the grid during summer’s peak loads,” Beckner said. “When we work together, the simplest actions add up to make a big difference.”
At day’s end, the Valley region is our shared home, Shultz said.
“My family is dependent on me keeping the lights on as much as I am keeping the lights on for the other 10 million folks in the Valley,” he said. “We want to do the best job we can. Reliability is always the No. 1 priority.”
