Rare Carrington-Level Solar Storm Could Cause Widespread U.S. Power Outages, Study Finds

The researchers based their model on a Carrington Event, a geomagnetic storm with a 1-in-150-year likelihood or rarer, and found the most vulnerable areas are the Northeast and the Northern Plains, especially higher-latitude locations. The study estimates power disruptions for 5.1 million people and 135,000 businesses. Outages could last from hours to days to weeks depending on damage and available restoration resources, said Ed Oughton, lead author and a researcher at George Mason University. “We haven’t really seen events like this size in the modern era, where we’ve had all of this high technology and we’ve had the power grid of this size,” he said.

No one knows when the next big storm will arrive. Anna Kelbert, a geophysicist at the Harvard-Smithsonian Center for Astrophysics who was not involved in the study but previously studied solar storm effects on power grids, said such events do not follow a fixed schedule. “That timing only averages out on very long timescales. The event can occur at any time, as soon as a week from now, or centuries later,” she said. She added that the analysis shows the United States is “currently ill-prepared to face a major magnetic storm, and that the societal impacts would be catastrophic.”

Shawn Dahl, service coordinator at the Space Weather Prediction Center operated by the National Oceanic and Atmospheric Administration in Boulder, Colorado, said the sun is now coming down from a period of heightened activity, which is also when some of the biggest storms to hit Earth have occurred in the past. “We still need a lot of work to be ready,” he said.

Because the U.S. grid’s actual structure is proprietary for security reasons, the researchers used engineering models to create various network and transformer setups, including the 10,464 substations and 16,256 transmission lines found across the country. The grid structure itself contributes to higher risk in some regions. The eastern U.S. is linked in a single grid interconnection, so a voltage issue in Maine, if not isolated early, could cascade through the grid to Washington, D.C. The West works similarly, while the Texas interconnection operates mostly within the state. Power restoration would depend on alternative electrical paths that bypass damaged substations and on the availability of spare transformers.

Editor’s Summary: The study provides the most detailed national modeling of how a rare geomagnetic storm could hit the U.S. power system, with 5.1 million people and 135,000 businesses projected to lose power and daily economic losses reaching billions. Experts stress that such storms can occur at any time and that the country remains unprepared.