Can NBC’s new fall drama “Revolution” — about a post-apocalyptic world devoid of electric power — turn the lights on for a network struggling to find a hit at 10 p.m.?

The series opened well in its premiere Monday but its long-range durability is still unknown.

The 10 p.m. question that applies across the broadcast network spectrum. What was once a reliable time period — home to Emmy-winning dramas that were also top-10 staples, like “ER,” “Law & Order” and “NYPD Blue” — has become something of a programming wasteland of late for ABC, NBC and CBS.

Between the dominance of reality and comedy in the 8 and 9 p.m. hours, declining ratings overall and the aggressive push basic cable has made in recent years slotting in watercooler dramas and reality crowd-pleasers at 10 p.m., conventional wisdom has been that securing a broadcast hit at that time is harder than ever. (And when something popular does arise, like ABC’s “Revenge,” it often gets moved, as it will this fall to the better-performing 9 p.m. hour.)

“You have so much competition, and you still have really high budgets on scripted programming,” says Deana Myers, a senior analyst at SNL Kagan. “The license fees on those are still really high. So it’s tough, and it’s been tough for a long time.”

Still, people are taking notice of some strong potential in the nets’ fall lineups, starting with the fact that, hey, they still believe in 10 p.m. to begin with as a place for adult drama.

“The good news is that they’re still programming in the time period, that they haven’t turned it over to the affiliates,” says Horizon Media senior research veep Brad Adgate. “Some of the new shows that critics have been very high on this year are 10 o’clock shows. It looks like they’re making a concerted effort to reinvigorate the time period.”

Examples include the aforementioned “Revolution” on NBC, from high-concept impresario J.J. Abrams, and ABC’s Connie Britton starrer “Nashville,” a seriocomic soap set in the world of country music.

CBS, meanwhile, continues to show its belief in the power of crime dramas at 10 p.m. — previously seen in Sunday’s “The Mentalist,” currently the time period’s most-watched show on any broadcast network, and returning shows “Blue Bloods” (Friday) and “Hawaii Five-O” (Monday) — by scheduling “Elementary,” a contemporary reworking of Sherlock Holmes that takes place in New York, on Thursday and the ’60s-set “Vegas,” a mixture of western, mob saga and procedural centered on the historic expansion of Sin City, on Tuesday.

With DVR playback of recorded shows from earlier in the evening often cited as one of the primary reasons the 10 p.m. hour isn’t potent real estate for the networks anymore, the fact that “Revolution” and “Nashville” have serialized storylines indicates an acceptance of delayed viewing by the big three.

“I think the networks are banking on DVR playback as an integral part of what viewers are going to do if they like these shows,” says Adgate, who cites NBC’s renewal of 10 p.m. musical drama “Smash” for midseason as a sign that instant ratings analysis isn’t what it used to be. “That show had a very high incidence of DVR playback.”