A new solar storm power outage study published in AGU Advances estimates that an extreme geomagnetic storm expected only once every 250 years could cut electricity to as many as 5 million people in the United States and drain $1.81 billion a day from the economy. The same scenario could affect more than 135,000 businesses.
That is the kind of number that turns a distant space-weather threat into a daily planning problem. It is also why researchers are searching for the study now: the Sun still looks far away, but the costs of its strongest outbursts would land fast on homes, hospitals, stores and the grid that keeps them running.
The study uses an integrated framework that follows the effects of space weather through the United States power system and into the wider economy. It ties together physics, engineering and economics to estimate what happens when the Sun throws off plasma and magnetic energy in coronal mass ejections, that energy reaches Earth’s magnetic field and creates geoelectric fields in conductive materials. Those currents can pass through extra-high-voltage transformers and interfere with electrical transmission, setting off outages that spread well beyond the point of impact.
The authors estimated that a 100-year storm scenario would still leave 3.5 million people and 91,000 businesses without power and produce $1.22 billion in losses each day. They compared simulated impacts at electric substations with measurements collected by the Tennessee Valley Authority during the 2024 Gannon storm, then used those results to show which grid investments could do the most to limit future damage.
The hard part is that space weather is still poorly quantified as a risk, even though it has already shown it can do real damage. In 1967, a solar storm nearly started WWIII after it disrupted U.S. early-warning radars and led American leaders to suspect the Soviet Union. Yet previous socioeconomic work has often stayed in separate slices, studying the physics or the grid or the costs, but not the chain that links them.
That missing link matters because the damage would not stop at the blackout. Extended outages can disrupt refrigeration, heating and cooling, internet service, medical equipment, fuel distribution and business operations all at once, and the same weaknesses that make geomagnetic storms so expensive also appear in aging equipment and weather-related outages. The authors say future work should look at chain-reaction effects inside the grid and at compound disasters, including a geomagnetic storm hitting during a heat wave, hurricane or other extreme weather event. That is the real question now: which upgrades protect the system best before the next extreme storm tests it.
