NEW YORK – With fall in sight, ABC is inviting viewers to stay home and watch ABC as an energy-saving measure.

For this tongue-in-cheek promotion, National Stay at Home Week begins Sept. 21 – also the official start of the 2008-09 TV season.

If only sky-high gas prices would guarantee ABC a captive audience.

Alas, it’s hard to make an argument that viewers are breathlessly awaiting ABC’s fall season – or any other network’s. Audience buzz remains at a hush.

With the networks still reeling from the disruption of last winter’s strike by screenwriters, only 17 new series have been slotted for fall – about half the usual number.

And most of them have been unavailable for preview. As the networks continue to play catch-up, few new shows have been put in front of critics, who, in other years, would have been warming up the crowd.

Not that there isn’t plenty going on. Broadcast networks were already dogged by audience erosion, growing competition from cable and the Internet and TiVo-equipped viewers who blow off the commercials.

These challenges are only intensifying now. So whatever the programming networks air this fall, there is likely to be drama, suspense and pratfalls as the networks race to adapt to a medium in flux.

Beyond that near-certainty, mostly questions prevail.

• For starters: Will viewers surprise the networks (and themselves) by discovering a hit among the limited fall prospects?

The most eagerly awaited entry is “Fringe,” Fox’s paranormal thriller from J.J. Abrams (“Lost,” “Alias”). It also happens to be an exception to all the new shows no one’s seen yet: Its 90-minute pilot was screened for critics way back in June and for fans at Comic-Con in July. For weeks, it could be downloaded by anybody else to sample from the Internet.

No one will be sampling “90210” beforehand – by design. The premiere will be kept under wraps until its Sept. 2 airing as a “strategic marketing decision,” the CW network recently announced. Thanks to that strategy, any buzz about “90210” is free to dwell on the likelihood it will fall far short of “Beverly Hills, 90210,” the 1990s cultural phenomenon that spawned it.

ABC is introducing just two new series. One, “Opportunity Knocks,” is a trivia-based game show. The other, a cop drama with a time-travel twist called “Life on Mars,” began life as a British series. But it’s not the only transplant this fall.

• Will global imports tighten their grip on the networks?

CBS’ wedding woes comedy, “Worst Week,” and its science-driven crime drama, “Eleventh Hour,” also have been adapted from British TV. NBC’s mother-daughter comedy, “Kath & Kim,” sprang from an Australian hit. CBS’ “The Ex List,” a romantic comedy, was inspired by an Israeli series.

They will take their place with successful imports such as NBC’s British-born “The Office” and ABC’s “Ugly Betty,” which originated as a Spanish-language telenovela.

It’s worth remembering that last fall, CBS belly-flopped with its version of the British hit “Viva Blackpool,” which, transformed into “Viva Laughlin,” lasted two weeks.

But for a decade, the networks have been mining reality and game-show formats from around the world with spectacular success (“Who Wants to Be a Millionaire,” “Survivor” and “Big Brother” are early examples). This fall, Fox is introducing a game show called “Hole in the Wall,” from Japan.

If any of the networks were to strike gold this year with scripted imports, it would likely spur an even bigger global shopping spree.

• But will more imports, or anything else, do the trick for NBC and its entertainment czar, Ben Silverman?

A 36-year-old wunderkind producer when he came to NBC Universal 16 months ago, Silverman inherited a fourth-place network whose Fall 2007 schedule was already announced.

Today, NBC, thanks to the Beijing Olympics, has crept ahead of ABC to claim third place in total viewers. But the Olympics and their explosive ratings are just a beautiful memory as NBC heads into a brand-new season, its fall schedule crafted by Silverman’s team.

Although he champions an inventive multimedia-platform approach to programming, his vision of what viewers want to see is oddly derivative: “Simple themes reinvented, accessible entry points, universality,” he rhapsodized when pitching the schedule last April.

But it remains to be seen whether Silverman’s stated mission – providing a video respite from the harsh modern world – will placate the restless channel surfer. Or whether other networks will convert to a similar gospel.

His new fall shows include “Kath & Kim;” a remake of the 1980s man-and-his-car hit “Knight Rider;” the self-explanatory “Crusoe;” and “My Own Worst Enemy,” an action drama about a family man with a split personality.

At the same time NBC unveiled its fall schedule, it also presented a schedule for midseason, reinvigorated with more new and returning series.

Other networks are also adopting this strategy of prearranged replenishment. It’s aimed at minimizing reruns and refreshing the lineup in an orderly way to keep viewers on board.

• But does alerting them this far ahead to all the shows awaiting them come winter undercut the effort to excite them about fall? Will the audience suspect the networks of holding out their best stuff for midseason, stuff like Fox’s spinoff from “Family Guy,” an NBC comedy starring “Saturday Night Live” alum Amy Poehler, and the return of ABC’s “Lost” and Fox’s “24”?

Long before then, the audience will be sizing up fall entries that also include a Fox comedy about a luxury Manhattan hotel, “Do Not Disturb,” and “Gary Unmarried,” a CBS comedy about a guy navigating his recent divorce. CBS’ drama “The Mentalist” focuses on a consultant to the cops who has a keen eye for clues but a dubious past. CW weighs in with “Privileged,” about a sexy live-in tutor in posh Palm Beach, and “Stylista,” a reality show where competitors vie for a job at a fashion magazine.

Still, it won’t be new shows that determine the outcome of the networks’ ratings race. The pivotal factor: Which network has the strongest slate of veteran series.

Several proven hits – Fox’s “House,” NBC’s “Heroes,” ABC’s “Desperate Housewives” and “Grey’s Anatomy” – are now awaited by viewers with eagerness that nothing new can match.

Whether returning shows like ABC’s “Dirty Sexy Money,” “Pushing Daisies” and “Samantha Who?” can reclaim their initial popularity after months on ice – that’s less certain.

But is anything certain as ABC sets the stage for Stay at Home Week? Right now, the networks’ biggest show is a guessing game, the one they’re trying to win.