5 U.S. power grids are rated high risk for shortfalls as electricity demand soars

Readers hunting for their own region on the North American Electric Reliability Corporation’s long-term risk map will find five names in its top tier: MISO, PJM, Texas RE-ERCOT, WECC-Basin and WECC-Northwest. NERC published the ranking in its 2025 Long-Term Reliability Assessment in January 2026. The report sets planned power supply against forecast demand over ten years, and the demand side has swelled by more than in any earlier edition.

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Five of the 23 assessment areas NERC studied reach its highest risk level inside the 2026-2030 window. Eight more sit one rung below.

MISO, PJM, ERCOT and two Western areas: the five at the top

In its Long-Term Reliability Assessment, NERC names the five and dates each one’s slide into the top tier. MISO, the grid operator for much of the central United States, is rated normal in 2026, elevated in 2027 and high from 2028 onward. PJM and Texas RE-ERCOT are each elevated from 2026 through 2028 and high from 2029. WECC-Northwest is normal through 2028 and high from 2029. WECC-Basin is described as elevated through 2028 and high from 2029, although the report’s detail table marks 2027 as high, an inconsistency inside the document.

NERC’s yardstick is a planning test. An area is high risk when its resource adequacy targets are not met, or when probabilistic or deterministic analysis shows planned resources leaving unserved energy or lost load beyond baseline criteria. One probabilistic trigger is an annual loss-of-load expectation above 2.4 hours a year; another is normalized unserved energy above 0.002 percent, or 20 parts per million. The NERC infographic frames the ratings around the first five years of the outlook, 2026 through 2030.

Eight areas one rung down, four of them in Canada

The elevated tier is where most of the rest of the continent sits. MRO-SPP, NPCC-New York and NPCC-Maritimes are elevated from 2026 onward, MRO-SaskPower in 2026 and 2027, and SERC-East from 2027. MRO-Manitoba Hydro and NPCC-Quebec join from 2029, and NPCC-New England is listed from 2029 in the report’s section heading even though its table shows normal risk. Four of the eight, SaskPower, Manitoba Hydro, the Maritimes and Quebec, are Canadian systems. With the five high-risk areas, the list accounts for 13 of the 23 areas.

NERC’s staff presentation to industry says resource adequacy concerns are spreading to more areas and growing more severe, and its industry webinar slides single out PJM, where the hours of risk are expanding into shoulder months. Texas RE, the regional entity covering ERCOT, posted its own summary of the assessment, which tests whether planned resources can meet demand over the next decade.

224 gigawatts of new summer peak, and who is asking for it

NERC says the aggregated summer peak will rise by more than 224 gigawatts over ten years, 69 percent above last year’s projection of 132 gigawatts. The winter peak is forecast to climb by more than 245 gigawatts, 65 percent above the prior 149 gigawatts. The webinar slides put the summer figure at 24 percent above 2025 peak levels, and Power magazine’s account of the report adds that the compound growth rates are the highest NERC has recorded since it began tracking in 1995.

Data centers are the largest single source, followed by industrial loads and electrification. In PJM, summer peak demand climbs by 56 gigawatts to 210 gigawatts by 2035, with winter rising 62 gigawatts to 198. ERCOT’s summer peak grows from 94,650 megawatts in 2026 to 154,077 megawatts in 2035, about 5.6 percent a year. MISO moves from 127 gigawatts to 143.7 gigawatts.

The smaller high-risk areas show the same upward slope in proportion. WECC-Northwest’s peak rises by 6.6 gigawatts, about 19 percent, and WECC-Basin’s summer peak climbs by more than 1.7 gigawatts, 17 percent. Among the elevated areas, NPCC-New England’s winter peak grows by 7.1 gigawatts, a 36 percent jump, and NPCC-Quebec’s peak rises from 41.4 gigawatts to 49.6. The ratings reflect how far demand outruns each area’s planned supply, not the size of the load alone. John Moura, NERC’s director of reliability assessment and performance analysis, was quoted by Power magazine calling the load growth real and describing the challenge as “a pace and scale of the system transformation.”

Retirements, slow interconnection and 390 delayed transmission projects

On the supply side, the webinar slides report that fossil-fueled capacity fell by 21 gigawatts, while batteries, solar and wind grew by 23 gigawatts, a mix that depends more on the weather. Gas-fired generation is growing too, with 53 gigawatts waiting in interconnection queues. Of nearly 900 transmission projects under construction or planned for the next decade, at least 390 have slipped from their expected in-service dates, and connection delays have trimmed capacity against earlier projections.

Winter is the sharpest exposure. Per Power magazine, solar output is near zero during winter peak hours, four-hour batteries may not fully recharge during a multi-day cold snap, and a growing dependence on gas raises fuel-supply questions in extreme cold. In ERCOT and PJM, data-center demand could push reserve margins below targets later in the decade.

Mark Olson, NERC’s manager of reliability assessments, said that many regions move into elevated or high risk later in the decade as demand rises and planned generation fails to keep pace. Whether the five stay at the top depends on projects that are not yet built, and the next edition of the assessment will show how many arrived on time. For now, the January 2026 report gives WECC-Basin two different start dates for its top rating.

This article was produced with the assistance of AI and reviewed by Morning Overview editors prior to publication.