Could a cyberattack shut down the power grid?

Yes. A cyberattack can shut down parts of a power grid, and real-world incidents have caused outages before.

A large-scale, long-lasting shutdown of an entire major grid is much harder to pull off than a localized outage. Power grids are distributed systems with multiple utilities, control layers, and manual fallback procedures, so attackers are more likely to cause regional disruption, temporary outages, or operational delays than a permanent nationwide collapse.

In practice, cyberattacks on grids often target operational technology (OT) such as industrial control systems and SCADA equipment. If attackers get far enough into those systems, they may be able to trip breakers, disrupt communications, or interfere with restoration efforts.

So the short answer is: yes, a cyberattack could shut down part of a power grid, and in serious cases cause major outages, but a complete, sustained shutdown of a large national grid is much harder and not the typical outcome.