The rolling blackouts experienced by electricity consumers in Tennessee in late December resulted in unprecedented targeted service interruptions and has placed Tennessee Valley Authority under the microscope.
The Newport Plain Talk reached out to TVA for further information, including an update on its internal investigation that led to the rolling blackouts and received a written response to our inquiry from Scott Fiedler, TVA media relations.
Fiedler stated TVA is still in the process of conducting a comprehensive review to better understand what happened and why so it can take action in the near, medium and long term to be better positioned to respond to extremes in the near future.
"It is important for your readers to understand that we have taken immediate action to prepare for the next storm" Fiedler said. "Since the storm, our employees have identified and completed over 200 near-term actions to improve resilience and performance in advance of the next event.
"As a result, I can report that we have not had any issues with the recent winter storm moving across our region. The grid is stable and operating as designed."
Preparing for extremes
Temperature extremes are not out of the ordinary, TVA notes: "In Tennessee Valley, we can see 100-degree annual temperature swings. In spring and fall, we prepare the electric grid for hot weather and bitter cold. This includes inspections, regular maintenance and equipment repairs. TVA has more than 32,000 megawatts of its own generation and 6,000 megawatts of contracts, which is more than enough to meet demand in most situations."
A 'once-in-a-generation storm'
Fiedler notes the National Weather Service referred to the December storm as a "once-in-a-generation storm" that resulted in record-setting power demand. On Dec. 23, TVA broke its all-time record for single-day energy demand as well as its highest winter peak power demand of 33,425 megawatts. It also experienced its highest weekend peak power demand in TVA history on Dec. 24 at 1 a.m. of 31,756 megawatts.
For comparison, TVA's average peak load is 22,600 megawatts and its hourly load system-wide for Dec. 23 was 36% higher than its average peak.
TVA's Cumberland facility, which provides approximately 2,500 megawatts of power, was impacted by extreme temperatures and high winds and went offline early Dec. 23. Critical instrumentation located at the top of the boiler faced the brunt of the extreme conditions, causing instrumentation to freeze and caused the units to go offline.
TVA also saw gas plants go offline and plans to offer more details on the gas plants once its review is completed.
Fiedler said TVA purchased and imported electrical generation from neighboring markets "as much as we could" but surrounding markets were also experiencing high demand. Notably the storm impacted every state except Florida and Hawaii.
End-use participants in Demand Response programs provided around 1,500 megawatts of relief and such actions were taken before TVA implemented its load curtailment (rolling blackout) procedures.
Any power disruptions associated with TVA's directive were intended to cause power interruptions of only 30 minutes or less.
Newport Utilities customers who were impacted typically experienced interruptions of 15 minutes.
TVA's investigation is ongoing. "This is not how we want to serve our customers, and we recognize we fell short of the public's expectations to deliver electricity 24/7, even under extreme conditions," it stated.
Its investigation includes a review of its actions both before and after the event. Areas it is focusing on include:
Facility winterization practicesPreventive maintenance activitiesEmergency operation plans, especially those related to its Emergency Load Curtailment ProgramCommunication with local power companies, industrial customers, key stakeholders and the public to ensure timely, accurate and actionable information is provided
A sense of urgency
TVA said its investigation will be transparent and will move with a sense of urgency. "We know there is work to do to fully restore confidence in TVA's ability to reliably provide the energy 10 million people count on and are committed to meet the expectation for the future," it stated.
TVA also provided, in response to The Newport Plain Talk's questions, more detail about TVA's rolling blackouts, its capacity and the potential impact of electric vehicles on its grid.
Load curtailments (rolling blackouts)
Fiedler said utilities monitor the grid in real time to balance the amount of generation versus the amount of power being consumed. TVA and local power companies, such as Newport Utilities, have an Emergency Load Curtailment Program (ELCP). The plan includes several interim steps.
In emergencies, such as the one experienced in December, utilities will quickly reduce the load by turning off power to customers in order to balance the system and prevent unplanned power outages. In this particular instance, local power companies were instructed to turn off power in a targeted, planned manner. It notes that each of its 153 local power companies has its own plan to implement load curtailments.
Fiedler stated that from FY2014 through FY 2022, TVA has invested $18 billion in capacity expansion and base capital. It plans to add 10,000-14,000 megawatts of new resources by the end of this decade.
"For example, we have added 3,700 megawatts of new generation and currently have RFP for 5,000 megawatts of carbon-free energy to be brought online by 2029," Fiedler noted. "We will have more information on who the winning bidders are this spring."
Fiedler said currently there aren't enough EVs to make a significant impact on energy available during the recent winter storm. However, TVA does expect many more such vehicles in the next decade. "We are taking steps and working closely with local power companies to prepare for this shift at the local and system-wide level.
"With local power companies, we are working to install the Fast Charge Network at approximately 80 locations, 200 fast chargers across seven states. This will ensure drivers will never be more than 25 miles from a fast-charging station."
At this time, there are less than 40,000 EVs in the Tennessee Valley, representing less than 1% of vehicles on the road and no impact to TVA, Fiedler notes.
It also was noted EVs currently have less impact on the electric grid than household appliances such as clothes dryers and water heaters and that the majority of EV charging occurs at homes during off-peak hours.
Earlier in the week, TVA announced it made $3 billion in operating revenue in the final three months of 2022.