Nightly at Broadway’s Walter Kerr Theater, Hades, the king of an industrial underworld, boasts of his “power chords and power lines” before bellowing, as the lights flash, “I conduct the Electric City!”

But on Saturday night, even the title character of “Hadestown” turned out to be powerless.

The blackout that darkened parts of Manhattan’s West Side forced the closure of all but a handful of Broadway shows — as well as movie theaters, Carnegie Hall, a Jennifer Lopez concert at Madison Square Garden, much of Lincoln Center and many smaller venues, stranding ticketholders and disappointing tourists who had flocked to performance venues for a Saturday night out.

[Update: Con Edison apologizes for New York power outage, but offers few clues about “root cause.”]

“There was a line of people outside waiting, so we hate to have to not do the show for them,” Aaron Tveit, one of the stars of “Moulin Rouge! The Musical,” which is now in previews, said disappointedly as he left the shuttered Hirschfeld Theater. “Hopefully everyone is just safe.”

The electricity failed about an hour before curtain for most shows, meaning the casts and crew were already in place and audiences were on their way.