On the day before Christmas Eve 2015, a cyberattack hit the power grid in Ukraine, shutting off power to about half the homes in the Ivano-Frankivsk region of the country.
The incident, which was blamed on Russia-based cybercriminals, marked the world’s first known successful cyberattack against an electric grid. Ever since, the question that has haunted American electricity providers and government officials has been: Can the same thing happen to the U.S. grid?