During Winter Storm Elliot last December, millions of people across the eastern United States went without power during one of the coldest periods of the year. Electric utilities in the Southeast performed poorly during the storm. In the Carolinas, 500,000 Duke Energy customers lost power due to rolling blackouts.

For the first time in its 90-year history, the Tennessee Valley Authority instituted rolling blackouts across its service area of 10 million people. Winter Storm Elliot’s outages left people unable to heat their homes and cook holiday meals, and for some communities, power outages can have life or death consequences.

So, what happened and how do we prevent this from happening again?

During the storm, Tennessee Valley Authority lost power due to failures in gas and coal plants while experiencing higher than expected electricity demand. As a result, people whose local power companies get electricity from the Tennessee Valley Authority experienced blackouts on Dec. 23 and 24. Meanwhile, in North Carolina, several of Duke’s fossil fuel powered plants were derated, producing less power than expected. At the same time, electricity demand was higher than anticipated and Duke was unable to purchase as much power as it needed from other utilities who were also impacted by the storm. This set of circumstances led the company to initiate rotating power outages.

There’s a lot to be learned from this horrible confluence of events. Let’s explore five key takeaways from Winter Storm Elliot last December.

1. Failures were caused by fossil fuels, mainly methane gas.

During Winter Storm Elliot, 90% of lost power in the eastern half of the US was from failures in gas, coal or oil burning generation and 63% of lost power was from failed methane gas-powered generation. Meanwhile, just 1% of lost power came from solar and 4% from wind.

Following this trend, fossil fuel plant failures were also a contributor to blackouts in the Southeast. In the TVA system, 10 of its 17 gas plants and four of its six operating coal plants had major generation issues that contributed to rolling electricity blackouts during the storm. Meanwhile, several of Duke’s fossil fuel plants in North Carolina were derated during the storm.

Graph from FERC-NERC-Regional Entity Joint Inquiry Into Winter Storm Elliott

2. Winter Storm Elliot was a “déjà vu” moment; we’ve seen it before — reliance on methane gas makes the U.S. electric grid vulnerable.

A top U.S. regulator referred to Winter Storm Elliot as “déjà vu all over again.” Why? Because we’ve already seen the U.S. electrical grid fail time and time again due to poor gas performance in winter weather. At the national scale, Winter Storm Elliot was the fifth event in the past 11 years where grid reliability was jeopardized by cold weather. Gas fuel issues were a common theme among all five events.

“These recurring failures make clear that America’s natural gas infrastructure and electric grid continue to be severely challenged during extreme cold weather events, repeatedly jeopardizing reliability during life-threatening conditions,” said the Federal Energy Regulatory Commission in a recent report.

Methane gas is the most significant fuel source for electricity in the United States, accounting for 40% of electricity generation nationally (and an even larger share in North Carolina). Here in the Southeast, the Tennessee Valley Authority and Duke Energy are leading the largest planned utility gas build-outs by 2030. Relying too much on gas for electricity production is risky because gas fuel supply is highly vulnerable during winter storms. During the storm, methane gas production fell by 16% in the lower 48 states, with the most dramatic decreases in the Appalachian region. Production fell while gas demand was high, leading to fuel shortages. Twenty percent of all power loss during Winter Storm Elliot was a direct result of gas fuel issues.

FERC Winter Storm Elliot Report

Cold weather gas shortages are further exacerbated by increased home heating demands. About 60% of U.S. homes use methane gas. Cold winter weather increases the need for home heating at the same time that electricity demand increases and gas production is at risk. As a result, methane gas supply struggles to meet high demand from both home heating and electricity generation during winter storms. The over-reliance on gas for both electricity and home heating makes US homes vulnerable to winter outages.

Because electricity production is over-reliant on methane gas and critical elements of the methane gas supply chain (such as electricity-driven compressors) depend on electricity to run smoothly — a failure in one system can lead to a failure in the other, leaving both systems vulnerable. The energy system is disrupted when electricity is unavailable to operate methane gas infrastructure (affecting gas fuel supply) or when methane gas is not available to operate power plants (affecting electricity supply).

3. Wind power helped keep the lights on across the country and could have had a larger role.

During the storm, renewable energy performed well across the country, with wind playing an important role. Strong wind generation prevented blackouts in the Midwest and allowed the Midwest grid operator, MISO, to help neighboring utilities by exporting power. Similarly in Texas, wind and solar generation exceeded expectations during the storm, while Texas’ winterized gas and coal plants performed poorly.

Wind energy could have played an even larger role in preventing blackouts, but limited transmission capacity on the grid prevented the export of power into the regions that needed it most. During the storm, the Midwest had an excess amount of wind energy, which went to waste while the Southeast was experiencing power shortages. If wind energy from the Midwest could have been sent to the Southeast during the storm, blackouts could have been reduced or prevented.

https://windexchange.energy.gov/states/nc

Similarly, more wind production in North Carolina could have produced desperately needed power during the storm. While there were strong wind speeds in North Carolina during the storm, Duke was unable to tap into this potential since the company has not significantly invested in wind turbines — wind accounts for just 0.4% of North Carolina’s energy generation.

Meanwhile, analysis showed that while solar alone would not have eliminated the North Carolina outages (since they occurred in pre-dawn hours), the service interruptions could have been reduced and shortened by solar paired with battery storage.

TVA also would have been better positioned for the storm if it had more renewable energy in its power mix. TVA currently generates less than 3% of its power mix from solar and wind combined, and relies on energy efficiency for only 1% of its power. During the storm, none of those resources were reported to be offline. Greater deployment of renewables and energy efficiency could help protect customers from outages during future winter storms.

4. More transmission capacity could have prevented or limited outages.

Interregional transmission, the system by which different parts of the country share power, provides resilience against weather events by allowing energy to be transported from areas that are not affected by a storm to those that are. In addition to preventing blackouts, more interregional transmission could have protected customers from high prices. An additional gigawatt — enough electricity to power 100 million LED bulbs — of transmission capacity into Duke territory in the Carolinas could have provided as much as $81 million in benefits by protecting customers from price spikes and outages during the storm.

Participating in an energy market, such as a regional transmission organization, is one strategy to improve resilience by increasing access to cheap and geographically diverse energy sources. A study found that joining an RTO could provide as much as $600 million in benefits to North Carolina customers per year, with $80 million in benefits coming from improved reliability. However, Duke is strongly opposed to joining an energy market, such as an RTO, and has lobbied against bills related to studying energy markets for North Carolina.

5. Since last year, Duke and TVA are moving in the wrong direction for reliability.

A year after Winter Storm Elliot, the power grid remains vulnerable to similar events. In fact, North Carolina and Tennessee are both at elevated risk of insufficient electricity supply during peak winter conditions this year. Meanwhile, Duke and TVA continue to invest in new methane gas infrastructure, falsely claiming that gas is the solution to the very reliability issues it caused during Winter Storm Elliot. Unfortunately, it is unlikely that these new gas plants will improve reliability since they are dependent on the same methane gas fuel system that failed so miserably in Winter Storm Elliot.

A critical year

Next year will be critical for our energy future in North Carolina and Tennessee.

The North Carolina Utilities Commission will consider Duke’s proposed Carbon Plan update, which calls for a massive gas buildout of 7.1 gigawatts of new methane gas plants by 2038. Duke is also expected to request approval for two new gas plants in 2024. Despite Duke’s intentions to double down on gas, the future is not yet set.

Likewise, the Tennessee Valley Authority has proposed the addition of eight new gas plants at a total of 6.6 gigawatts – most of which would be built by 2030. Because TVA is not regulated by a public utilities commission, decisions to build the new fossil fuel capacity will ultimately be made by its nine-member board of directors. Advocates, like Appalachian Voices, will continue to question the reckless buildout of methane gas infrastructure in our region. It will be a busy year, but we are ready for the fight. Advocates like Appalachian Voices will continue to question the reckless buildout of methane gas infrastructure in our region. It will be a busy year, but we are ready for the fight.

Both states have the tools to develop more reliable electricity grids. To improve resilience to natural gas failures during winter storms, Duke and TVA should invest in low-cost resources, like solar, wind, and battery storage, instead of building even more gas plants. North Carolina specifically needs to explore new solutions, such as joining a Regional Transmission Organization, that increase the availability of geographically diverse energy sources.

And in 2024, the Tennessee Valley Authority is finalizing its long-term energy plan, which will steer the public utility through 2050. While these long-term plans typically involve a public process that allows for stakeholders to engage, TVA’s process is notorious for its lack of meaningful public engagement. In response, advocates are holding a People’s Hearing in Nashville on Jan. 25 to provide an open forum for expert testimony and public comment on the future of energy in the Tennessee Valley.

We have far better options than gas. North Carolina and Tennessee can and should demand better from our utilities