A record-setting 90.5 GW, or 13% of the generating capacity in the Eastern Interconnection — the grid system covering two-thirds of the U.S. — failed to run or operated at reduced capacity during Winter Storm Elliott in December, Federal Energy Regulatory Commission and North American Electric Reliability Corp. staff said Thursday.
Gas-fired capacity accounted for 63% of the outages, followed by coal and lignite at 23%, oil at 4%, wind at 4%, and nuclear, solar and hydroelectric at 1% each, according to a staff presentation on a soon-to-be released report.
About 10 GW of gas-fired outages occurred when their firm gas supplies were curtailed by pipeline operators, staff said.
FERC and NERC staff found that 55% of the outages, “derates,” and failures to start were caused by freezing and fuel issues, and 41% were caused by mechanical and electrical issues, correlated to below-freezing temperatures.
For units with freezing issues, which accounted for close to a third of the outages, nearly 80% occurred at ambient temperatures that were above the units’ documented minimum operating temperatures, said Kiel Lyons, NERC senior manager for compliance assurance.
Also, 154 blackstart units — generators that are used to restart the grid after a widespread collapse — totaling 19 GW faced outages during Winter Storm Elliott, according to Lyons. Gas-fired generators accounted for 119 of those units, he said.
Southeastern utilities, such as Duke Energy and the Tennessee Valley Authority, conducted rolling blackouts of more than 5 GW of load during the winter storm, according to the presentation.
At the same time, Consolidated Edison of New York’s natural gas utility, which serves Manhattan, the Bronx and parts of Queens, was on the verge of a system collapse on Dec. 24 due to low pipeline pressure, David Huff with FERC’s electric reliability office, said. The utility maintained operations partly by using its liquefied natural gas facility, but if the system collapsed, it would have taken months to restore service, he said.
‘Deja vu all over again’
“This is too close,” FERC Acting Chairman Willie Phillips said, noting Winter Storm Elliott was the fifth time in 11 years there have been significant wintertime power outages.
The last five major cold-weather events shared similarities, such as widespread failures of power plants to run, drops in gas production and failures by some grid operators to accurately forecast their peak load, according to FERC and NERC staff.
“It’s deja vu all over again,” FERC Commissioner Mark Christie said.
Phillips reiterated his calls that Congress direct an agency to oversee reliability for the natural gas system.
“We need someone who is directly responsible for the reliability of our natural gas system and enforcing reliability standards for our natural gas system,” he said.
The U.S. power system has become more reliant on natural gas, with gas-fired capacity growing 11% to 564.2 GW in mid-2023 from 508.2 GW in mid-2016, according to FERC infrastructure reports.
Ensuring the power system can handle tough winter weather raises market design concerns, such as cost recovery for weatherizing power plants, according to Christie.
“In a lot of our [regional transmission organizations], independent power producers, if the market design doesn't support the expenditures for winterization, they're not going to do it and they're going to either retire or just get out of the market,” he said.
Also, the U.S. needs more gas infrastructure to reflect the “real energy transition” — the growing reliance on gas and away from coal, according to Christie. In 1990, coal made up about half of U.S. generation and gas contributed about 10%, primarily as a peaking resource, Christie said. Those numbers have roughly flipped, and gas-fired power plants are now used as a baseload resource, he said.
Also, the gas system was designed to serve local gas utilities, not power plants, Christie said.
“This gas electric coordination is really not just about a bunch of people sitting in a room and then figuring out some document they can agree to,” Christie said. “It's about how do you take a system that was built to serve local distribution companies and their regional customers and turn it into a system that's going to provide sufficient supply for generating units that are running as baseload?”
FERC Commissioner James Danly said the coming report on Winter Storm Elliott indicates the U.S. has failed to build enough natural gas infrastructure, largely because of roadblocks at the agency.
He also warned FERC may be too focused on how winter weather can affect the power system, without giving enough thought to how it affects gas customers.
“A few hours of electric interruption is one threat, but compare that to what happens if every pilot light in the whole of Brooklyn goes out,” Danly said. “We need to discipline ourselves when we think about this subject, not to get fixated solely on the very easily measurable consequences to the electric system.”
FERC Commissioner Allison Clements echoed Phillips’ call for action from Congress.
“Congress needs to give us instruction on how to ensure that natural gas infrastructure can withstand this collective stress, and short of that, the burden is on us,” Clements said.
Also, just building more pipelines and other gas facilities won’t solve the problem, according to Clements.
“The infrastructure that was there didn't work,” she said. “From the [natural gas] production head through generation we saw failures.”
Interregional transmission helped the PJM Interconnection avoid power outages by allowing the grid operator to import power from New York and the Midcontinent Independent System Operator, Clements said.
“I urge the commission to take a holistic approach to our reliability responsibilities and to consider prompt action in our open interregional transfer capability docket,” she said.
FERC, NERC staff recommendations
FERC and NERC staff made a series of recommendations, including:
- NERC should identify and examine by the end of this year power plants that are at the highest risk of failing to run during extremely cold weather;
- NERC should launch a technical review early next year to determine steps power plant owners could take to prevent cold-related mechanical/electrical generation outages and determine if additional standards are needed;
- NERC should also study the readiness of blackstart units to run in cold weather;
- Congress and state lawmakers should pass legislation establishing reliability rules for gas infrastructure;
- An independent research group should analyze whether additional gas infrastructure, including interstate pipelines and storage, is needed to support grid reliability and the needs of local gas utilities; and,
- Balancing authorities should assess whether new or revised processes, such as multi-day risk assessments, advance or multi-day reliability commitments, are needed to help handle capacity shortages or transmission system-related reliability problems during well-forecast extreme cold weather events.
NERC has been developing cold weather reliability standards. The organization expects to propose a third round of standards for FERC review in October, Jim Robb, NERC president and CEO, said Thursday during a media briefing. It also plans to respond to FERC’s partial approval of a set of standards earlier this year with a revised proposal in February, he said.