More than half of the United States is at risk of electricity shortages this winter due to regional generation shortfalls, increased demand for power and potential fuel delivery challenges during sustained cold weather events, the North American Electric Reliability Corp. says.

NERC’s Winter Reliability Assessment, released Nov. 8, “again shows that our nation faces looming grid reliability challenges while demand for electricity continues to soar,” said NRECA CEO Jim Matheson. “That’s unacceptable and should be cause for concern for all Americans.”

John Moura, NERC’s director of reliability assessment and performance analysis, cited uncertain performance of renewable generation and increased seasonal demand for natural gas as factors raising concern over the grid’s vulnerability during winter weather.

“There is not enough gas pipeline to serve all the generation in certain areas,” Moura said.

NERC analysts cited several potential performance weaknesses impacting grid operators and transmission associations including the Tennessee Valley Authority, PJM and the Electric Reliability Council of Texas.

“Areas at elevated risks extend over two-thirds of the continent,” said Mark Olson, NERC’s manager of reliability assessments. He cautioned that natural gas generation could be threatened by fuel supply issues during prolonged cold snaps and coal-based generation can also face operational issues and unscheduled outages during winter peaks.

“About one-third of the natural gas outages that occurred during Winter Storm Elliott were due to fuel shortages,” said Moura. “In Texas, during Winter Storm Uri, there were production shortages caused by frozen wellheads.”

NERC’s report warned of rolling blackouts similar to those experienced last winter in the Southeast and portions of the Northeast and expressed concern about potential reserve shortages impacting consumers in Texas served by ERCOT.

When renewable generation declines, other resources must be available to balance load, Olson said. “Short-term load forecasting is becoming more challenging as generation options get more complex,” he said.

He urged utility operators and state regulators to work together to address projected generation demand before shortages occur.

NERC analysts also noted that SERC Reliability Corp., which oversees generation and transmission across TVA’s service territory and includes the Carolinas and several central states, could be plagued by electricity shortages due to increased demand with little change in available supply.

“Those areas were hard hit during Winter Storm Elliott,” said Olson, warning that conditions similar to the widespread freezing event last December could lead to demand shortfalls for both SERC and PJM, the independent system operator for much of the Mid-Atlantic region.

NRECA is urging policymakers to recognize that their decisions can impact grid reliability, increase chances of rolling blackouts and hurt the nation’s economy.

“Policies like the Environmental Protection Agency’s recent power plant proposal will magnify today’s reliability challenges with grave consequences for an already stressed grid,” said Matheson. “I don’t think EPA thought about electric reliability as it drafted this rule.”