A year after devastating winter storm, power plant problems ‘still likely’ in extreme weather 

Nearly a year ago, a Christmas weekend storm blasted across the country, forcing utilities to cut electricity to hundreds of thousands of people in parts of the southeastern U.S. after temperatures plunged, demand spiked, large numbers of power plants failed and natural gas supply was strained.

As the anniversary approaches of Winter Storm Elliott, a pair of reports released last week reveal how much worse the situation almost became and the continued vulnerability of the U.S. energy grid to frigid weather.

“The power plants that we had last year are the same ones we have this year,” said Simon Mahan, executive director of the Southern Renewable Energy Association, a trade group. “Sure there might be some window dressing weatherization efforts that have gone on but there’s no real way to determine if that’s going to be good enough going into this year.”

A joint inquiry into Elliott by the Federal Energy Regulatory Commission and the North American Electric Reliability Corporation, also illustrated that, despite the blackouts, a larger catastrophe for the New York City area was barely averted and the grid serving the entire eastern half of the U.S., called the Eastern Interconnection, was also at risk. Among many other recommendations, it calls for congressional and state legislative action to create reliability rules for natural gas infrastructure to ensure it functions in cold weather

“The report highlights what I’ve called for before: Someone must have authority to establish and enforce gas reliability standards,” said FERC Chairman Willie Phillips.

The other report, NERC’s winter reliability assessment, found that about two-thirds of the country this winter remains at “an elevated risk” of insufficient energy supplies to meet demand in severe conditions.

“Industry cold weather preparations are on a positive trend but generators and fuel supplies in warmer zones are still likely to have performance issues in freezing temperatures,” read a NERC presentation to reporters last week.

‘A real world of hurt’

Mahan, who was living in Texas during Winter Storm Uri in 2021, when millions of people endured blackouts lasting days and an estimated 246 people died, said Elliott posed a similar threat to the entire eastern U.S.

“We were way closer than what a lot of folks realize and too close to have basically done nothing about it in the last year,” he said. “I’m always at a loss to explain to folks how close things were and how dangerous it was because I don’t know if there’s enough adjectives to describe it.”

Gas pressure dropped so low in the system serving parts of New York that, had Con Edison, the gas provider, not taken emergency actions and the frigid temperatures abated, the system was close to a “complete loss” that would have taken months to bring back online, the joint report says.

Jim Robb, NERC’s president and CEO, said at a FERC technical conference on Nov. 9 that New York City dodged a disaster that would have “far exceeded” the 2003 summer blackout, the largest power outage in U.S. history.

“Had that cold front persisted one more day we would have been in a real world of hurt in the Northeast,” Robb said.

In North Carolina, Duke Energy’s struggles also risked a broader grid collapse, with frequency dropping over the weekend.

“Ultimately on the morning of Dec. 24, grid operators maintained frequency by reducing electricity demand, including by shedding over 5,400 MW of firm load, leaving hundreds of thousands of customers without electricity to heat homes for several hours during the extreme cold weather conditions,” the report says.

The term “firm load shedding” means reducing or discontinuing gas in the transmission system to keep the network safely pressurized.

The joint inquiry noted that Elliott was the fifth event in the past 11 years in which cold weather forced power plant outages that jeopardized the bigger grid. All told, more than 1,700 power generating units saw 3,565 unplanned outages, derates (a loss of generating capacity) or failures to start. Including power plants that were already offline before the storm, about 18% of the anticipated power supply in the U.S. portion of the Eastern Interconnection was unavailable during the worst part of the storm.

As the electric grid has become more reliant on natural gas power plants (which provided about 40% of power generation in 2022) it’s also become more vulnerable to gas system failures. And freezing weather makes it harder to get gas to power plants just when it’s needed most.

“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, even when technology exists to protect the vulnerable components,” the report says, noting the primary causes of unplanned generation outages as “freezing issues, fuel issues and mechanical/electrical issues.”

The push to winterize

New cold weather reliability standards developed by NERC after a 2018 cold snap for power plants became effective April 1. They included new requirements to maintain and implement cold weather preparedness plans for freeze protection, annual inspection and maintenance rules and training requirements, among others. But after Uri in 2021 demonstrated a clear need for stronger standards, FERC approved new rules earlier this year, though it told NERC to revise some of the applicability criteria. In October, NERC’s board adopted two new reliability standards for extreme cold weather.

“It is a complex challenge,” said John Moura, NERC’s director of reliability assessment and performance analysis. He noted that the electric system was built around summer peaking, though in recent years winter reliability has emerged as the major concern, mostly because of the rise of gas plants.

The development of standards has been slow, he acknowledged, but because it’s a collaborative “stakeholder” process at NERC, they’re created in concert with industry, less litigated and more likely to stick, Moura said.

“While it might take a long time, the end product is extremely valuable and something everyone gets behind,” he said. “Yes, it’s taken some time but we think we’re getting to that final answer.”

In the meantime 

The Tennessee Valley Authority, which was created in 1933 and had to impose rolling blackouts during Elliott for the first time in its history, says it has “undertaken a massive effort” since the storm to make winterization upgrades on its generation fleet at a cost of about $8 million.

“Mother Nature may hit us hard again this winter, but we have done the hard work — the necessary work — to ensure that we can safely and reliably provide power to our 10 million customers across the valley,” said Allen Clare, a TVA vice president. Louisville Gas & Electric/Kentucky Utilities, which was also forced to cut power to customers during the storm, said it “is looking at potential process improvements, such as public messaging and projects at plants to minimize valve freezing and other cold weather impact,” per the joint report.

Duke Energy, which initiated blackouts that affected about 500,000 customers in the Carolinas, faces an inquiry by regulators in both states. South Carolina’s Office of Regulatory Staff found numerous “areas for improvement” in the company’s cold weather preparations, noting that Duke significantly underestimated demand, failed to make supply planning adjustments and update forecast estimates, experienced plant and software failures and had problems communicating effectively with customers. An inquiry into cold weather reliability of gas, water, wastewater and electric systems that was initiated in 2022 by the North Carolina Utilities Commission remains open.

In a statement to a South Carolina news station, Duke, which agreed to a corrective action plan and said it has competed the majority of the 101 action items identified, added that it “learned from that historic day and continue to use what we’ve learned from this regional event to help deal with unusual and severe weather in the future.”

The nation’s largest grid operator, PJM, which coordinates the flow of electricity for all or parts of 13 states and the District of Columbia, was not forced to resort to rolling blackouts during Elliott. But it alarmed electric grid experts when it begged customers in its region to conserve electricity, since it was known to have a huge surplus of generation capacity.

In the wake of the storm, PJM is asking FERC to approve changes to its capacity market, which is intended to make sure there’s enough electric supply at critical times by providing extra payments to generators who commit to being available when demand spikes. PJM says they’re “designed to support reliability of the electric grid now and in the future amid increasingly extreme weather and a changing generation fleet.” The reforms are intended to better reflect actual risk of outages by generation type (such as common failures by natural gas plants), get more accurate accreditation of power sources to better assess their value to the grid and “improve generator testing, including operational and seasonal requirements.”

The proposed changes are a mixed bag, according to Tom Rutigliano, a senior advocate with the Natural Resources Defense Council’s Sustainable FERC project who focuses on PJM. He called reforms that more accurately take into account gas plants’ reliability risks a good step but criticized a plan to reduce penalties for generators that are paid to be available when called upon but fail to deliver.

“They’re betting that the savings from cost cutting will be more than the penalties they might have to pay,” Rutigliano wrote. “Reducing penalties is a direct message to power plant owners that they should spend less on preventative maintenance and preparation for emergencies.”

‘The rhythm of it all’

In an interview, Rutigliano said the fresh memory of Elliott in the minds of grid operators, power plant operators and utilities could be enough to instill vigilance in the event of severe weather this winter.

“If the past is any indicator, you have these freeze-offs and big problems that largely come down to negligence,” he said. That’s followed by a period of heightened awareness with lots of “sub rosa” actions that grid managers, utilities and other power system operators can employ to tighten up, he said. Unfortunately though, that tends to slacken after a few years, he added.

“That seems to be the rhythm of it all,” Rutigliano said. “I’d be less worried this winter because cold weather performance is on every power plant owners’ mind.”

Mahan, of the Southern Renewable Energy Association, said getting state utility commissions to better vet winterization efforts, improving power demand forecasting, diversifying generation resources, building more transmission to better link regions and getting new power sources like wind, solar and storage connected to the grid all have a role to play in protecting reliability.

“There’s no silver bullet,” he said. “With something like this, having a multi-pronged approach is the way to prepare for the future. … When you go into the woods you want to have a Swiss army knife.”

Getting gas right 

In the long run though, major regulators like NERC and FERC agree, toughening winterization standards and Congressional action on improving the reliability of the gas system and forcing better coordination with the electric power industry are necessary.

“The electric utility network is highly dependent upon the uninterrupted performance of the gas production and delivery network,” a report issued by the North American Energy Standards Board issued in July says. “Without the latter, the former cannot meet its own performance requirements.” When the gas system fails to deliver for power generation, the results can be catastrophic, the authors wrote.

“During Uri, gas needed for power generation vanished during periods of peak winter demand for both gas and electricity, tragically resulting in excess of 240 lives lost and economic damage estimated as high as $130 billion,” the report says.

The board made 20 recommendations. Some had broad support by both the electric and gas sectors, such as more state encouragement of demand response programs (which can cut electric and gas demand when supply is insufficient), aligning industry scheduling timelines and changing strategies for “unit commitment,” which refers to deciding when and which power generating units will start and shut down.

Others, however, like timely reporting of natural gas pipeline website data and encouraging states to “consider the development of weatherization guidelines appropriate for their region/jurisdiction” were generally widely supported by the electric industry but drew more opposition from the gas sector.

“As much as we are heartened by the strong support for some recommendations, the divergence of support between the two sectors on others is profoundly disturbing,” the report says. “it reflects a fundamental lack of agreement regarding the lessons learned from these past two winters and the challenges ahead in ensuring that outages no longer occur owing to a failure between these two systems. … We did not regard any of our 20 recommendations to be so burdensome or so profoundly altering that they would engender strong opposition.”

Lisa Sorg contributed reporting from North Carolina.