OK so NYC has yet another big black out. It’s happened before, recently even, with a death toll in the negligible.
A blackout that last a few hours for most it very different than a blackout that last for weeks.
The blackout of 2003 that shutdown the Northeast was simple cascade of controlled breaker trips. All of the systems remained intact.
Take out the central control system and bringing the grid backup will be extremely difficult.
Imagine if the terrorist coordinated attacks on several system operations centers in the Northeast.
Imagine if they did it in January.
Some other ideas set off an EMP near a major Airport. Set off a coordinated EMP attack airports in Boston/Philadelphia/Washington area. How about setting off EMPs near oil refineries.
Yes you won’t have big body counts but there will be deaths and their will be huge cost.