The Tennessee Valley Authority holds the capacity for nearly 34 gigawatts of nuclear, fossil fuels and renewables. That capacity is supposed to hold up in worst case scenarios like Arctic blasts.
When temperatures dropped to single digits across Tennessee last weekend, however, some of that fossil fuel generation froze, triggering rolling blackouts.
This all happened as Tennessee set new records for electricity demand. TVA reported its highest winter peak demand of 33.4 gigawatts at 7 p.m. on Friday, Dec. 23, and the highest 24-hour electricity demand that day with 740 gigawatt-hours.
At the same time, two coal plants, the Cumberland Fossil Plant and the Bull Run Fossil Plant, were at least partially down.
TVA said there were issues at gas plants but did not provide details about the specific plants or how they were impacted during the storm. Winter weather can impact the entire natural gas system, from frozen drilling equipment and pipelines to plant failures.
“We have not seen much transparency out of TVA,” said Daniel Tait, COO of the nonprofit Energy Alabama. “We would argue and expect a lot more open, honest and transparent communication from TVA to tell the public exactly what’s going on and what happened so we can learn from it and do better in the future.”
TVA said it was generating about 23 GW on midday Friday, about 7 GW short of what was needed.
With insufficient generation and not enough imports from neighboring grids, TVA ordered rolling blackouts from its local power companies like the Nashville Electric Service, which voluntarily cut power to customers in intermittent intervals.
NES rotated blackouts between 320,000 customers in total, with 72,000 people affected at peak. NES has not provided data on who lost or maintained power but said it targeted feeder circuits that weren’t connected to critical facilities like hospitals.
Before the rotating outages, NES said that between 2,000 and 4,000 customers were without power “due to typical storm-related issues.”
This has been my worst Christmas/holiday season because of the power outages, helping neighbors with burst pipes, shutting off main water lines, picking another neighbor up with a flat tire after he went to help a neighbor with frozen pipes… and the list goes on.
— JazzySabrina (@jazzy_sabrina) December 25, 2022
I've gone through my third rolling blackout this morning. Really messes up baking. https://t.co/TsQz5RSxNF via @tennessean
— Gene Bryant (@GeneBryant2) December 24, 2022
Arctic blasts projected to become more common
The Arctic has warmed nearly four times faster than the rest of the planet in recent decades, much faster than previously thought, a recent study found. This rapid climate change has been stretching the Arctic polar vortex, which is the band of strong winds normally lassoed around the North Pole and the northernmost polar air. When weakened, the polar vortex can dip south and push frigid air over Canada, the U.S. and parts of Asia.
This phenomenon is projected to make severe winter weather like this most recent event more common, according to a study in Science that reviewed data from 1980 to 2021.
TVA did not respond to a question from WPLN News about how climate change and the projected increases in winter storms would affect their current power plans.
TVA is building more gas plants
To manage winter demand, TVA has opted to build more gas plants, like the heavily-contested 1.5 GW plant near Clarksville, the planned plant for Kingston, and the approved Humphreys County facility, which the Southern Environmental Law Center alleged did not have its climate impacts fully considered by TVA in a lawsuit this week.
This strategy proved to be problematic this past weekend for TVA, which was not the only utility impacted. The reliability of natural gas during winter storms has been questioned more closely since the events of the February 2021 storm in Texas. A recent report found that natural gas and coal capacity in the U.S. may be overestimated by more than 20%.
In other words, adding more fossil fuels to the grid won’t prevent blackouts.
Two commonly touted solutions for winter electricity demand actually don’t involve building any new generation: utilities can use less power overall through energy efficiency and conservation programs.
Energy efficiency is the cheapest solution
Utility business models tend to encourage higher energy sales and investments in new energy sources, but utilities have the option to invest in energy efficiency — the cheapest energy source — as a way to help meet demand and lower electricity bills. States can also incentive these investments with certain policies.
Energy efficiency programs could shave off 26% of demand from Tennessee houses. The most cost-effective solutions include replacing electric heaters with heat pumps, improving wall, attic and HVAC insulation, and using smart thermostats and LED lighting, according to the U.S. Department of Energy. The Inflation Reduction Act provides direct savings for households to make some of these energy efficiency improvements, such as the $8,000 discount for heat pumps.
In 2020, the Southeast held the lowest amount of energy efficiency as a percentage of electricity sales at just 0.2%. Tennessee accounts for nearly 11% of electricity sales in the Southeast, but contributed just 3.7% of the region’s electricity savings, according to the latest report from the Southern Alliance for Clean Energy.
TVA had just .06% energy efficiency as a percentage of retail electric sales in 2020, two years after the utility ended most of its efficiency programs, according to the report. Earlier this year, some members of Congress questioned TVA on its lack of energy efficiency investment.
The lack of investment by TVA is adding costs to its customers. Tennessee residents consumed nearly 25% more electricity each month in 2020 than the national average, the second highest rate in the nation.
Inefficient heating plays a large role in consumption and costs. During rolling blackouts, older appliances in uninsulated homes will take a greater amount of energy to reheat the home after periods without power – leading to spikes in people’s energy bills.
“Inefficiency is straining the grid and costing people boatloads of money,” Tait said.
Great can't wait to get the bills for this.
— CrashTheHound (@CrashTheHound) December 27, 2022
‘Pretty much status quo’
To further reduce demand, TVA could also consider demand response programs, which are designed to help shift the timing of some energy devices like water heaters or washing machines to reduce use during peaks.
TVA or power companies like NES asking people to conserve energy is one form of demand response — but it can be automated.
“Energy efficiency and demand response are more than capable of helping to bring that peak down,” Tait said. “TVA hasn’t invested in any of those solutions. It’s been pretty much status quo.”
TVA’s latest planning document shows that greater energy efficiency and demand response market depth could reduce the need for 4 GW of extra power.
Instead, TVA bet on gas.
TVA did not respond to questions from WPLN News about the power plant failures or whether TVA would be reviewing its use of energy efficiency or demand response.
In a press release, TVA said it takes “full responsibility for the impact” on customers.
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