Two-thirds of the U.S. could face energy shortfalls during periods of extreme heat this summer, the North American Electric Reliability Corp. warned this week.

In its Summer Reliability Assessment released Wednesday, NERC said that there is an increased number of areas at an elevated risk of “insufficient operating reserves” if demand spikes, such as during summer heat waves.

These threats to the grid are “unacceptable,” said NRECA CEO Jim Matheson. “This report is an especially dire warning that America’s ability to keep the lights on has been jeopardized.”

NERC’s report cites retirements of conventional generation, substantial increases in electricity demand, and an increase in widespread summer heat events as factors contributing to their assessment. 

“More parts of the system have resource and energy risks during more extreme scenarios,” said Mark Olson, NERC’s manager of reliability assessment. “Demand growth and generation retirements take away flexible dispatchable generation that is needed to maintain reliability over a range of conditions.”

Additional reliability challenges highlighted in the report include: 

• Recent EPA rules that may force generators to meet “emissions restrictions primarily by limiting hours of operation.”
• “Fuel delivery risks” related to the availability of natural gas and coal.
• Supply chain challenges.

NERC analysts cited warmer-than-average weather and periods of reduced output from renewable resources like solar as particularly vulnerable times when grid reliability may be most at risk. 

The report warned of potential problems in California and the Pacific Northwest, the Southwest, much of the Midwest and New England. It placed the Mid-Atlantic region and the southeastern United States at lower risk for reliability issues, despite many states in that region having experienced rolling blackouts last December. 

“Going back at least five years, NERC’s reliability assessments have noted a steady deterioration in the risk profile of the grid,” said John Moura, NERC’s director of reliability assessment and performance analysis. 

NRECA and other utility interests have pressed policymakers to help address these growing reliability challenges before it is too late.  

“American families and businesses expect the lights to stay on at a cost they can afford. But that’s no longer a guarantee,” Matheson said, pointing to rolling blackouts in nine states last December as the demand for electricity exceeded available supply.

“Proposals like last week’s EPA power plant rule will greatly compound the problem. Absent a major shift in state and federal energy policy, this is the reality we will face for years to come. It’s vital that policymakers work to prioritize reliability in every energy policy discussion.”