Not all of our power grid’s potential disruptors are human enemies. One of its biggest threats, paradoxically, comes from the same heavenly orb that makes life possible on Earth: the Sun.
While you may not be aware of it, the Sun has weather, just as we do. But solar storms are a lot nastier than our heat waves and tropical storms, because they spew out mind-boggling blasts of radiation that can surge across the 93-million-mile distance between the Sun and our planet, and cause an electromagnetic pulse similar to the one that a high-altitude nuclear blast would trigger—except that it might be even bigger, and have even more devastating effects.
The effect of solar weather upon the electrical system is something that people have known about since even before the nation’s electrical grid was built. Back in 1859, telegraph systems in the U.S. and Europe abruptly failed after a large solar flare called the Carrington Event (after astronomer Richard Carrington, who documented it). But the first really clear-cut warning came in 1989, when a moderate-intensity solar storm caused northeastern Canada’s Hydro-Quebec generating station to fail, leaving millions of people without electricity for nine hours, according to a National Research Council report.
Yousaf Butt, a scientist at Center for Astrophysics at Harvard University, argued in a 2010 article in the online journal Space Review that the likelihood of a devastating EMP from a solar storm is greater than that from an intentional EMP attack.
Indeed, according to the National Academy of Sciences, a blast of charged particles from the Sun could destroy 300 or more of the 2,100 high-voltage transformers that are the backbone of the U.S. electrical grid. That might be enough to crash the entire system. Scientists have estimated that there's as much as a seven percent chance of such a catastrophic solar storm occurring over the next decade.