These days, if you put on a production of Richard Wagner's monumental "Ring" cycle, "Der Ring des Nibelungen," you're obliged — for better or worse — to come up with a novel concept.

It could be an exercise in Romantic realism, as Wagner himself envisioned it, gods and mortals in horned helmets and bear-skin costumes. It could depict the Industrial Age and its war against nature. Or it could go abstract, offering timeless, universal truths and Jungian archetypes on a bare convex disc with quirky lighting effects. All have been tried.

For its production of "Das Rheingold," the first of the four "Ring" operas, the prelude to Wagner's epic rumination on greed, power and lust, Minnesota Opera has taken a bold step to a place we have reason to believe no opera company has ever gone before. It has moved the orchestra onto the stage of the Ordway Music Theater, turned the orchestra pit into the Rhine River and the Nibelheim underground — key settings for the story — and placed some of the action, the activities of the gods, on a bridge above the orchestra, leaving the downstage area in front of the orchestra for the mere immortals.

This is chutzpah born of necessity. The Ordway pit, it turns out, isn't big enough to accommodate the expanded orchestra that Wagner requires. So the 80 or so players and their conductor, Michael Christie, sat upstage in the dark, trying to look unobtrusive.

This worked better Saturday night than one might have anticipated. Sound balance between orchestra and singers, always a problem in Wagner, was actually enhanced. The singers, at least those on the lower level, didn't have to sing over the orchestra, as is normally the case. And to avoid the impression that this was simply a concert version of the opera, director Brian Staufenbiel and his team came up with often intriguing visual motifs — chiefly video projections, the clever work of David Murakami that adds both atmosphere and a certain amount of narrative thrust.

The production design, with lighting by Nicole Pearce, suggests a future world. Mathew LeFebvre's imaginative costumes evoke sci-fi — post-Flash Gordon, more in the vein of "Mad Max." Creepy images of bugs proliferate. And there are hints, all rather vague, that some of the characters might be robots — replicants, perhaps.

Staufenbiel's cast is strong. As he usually does, Greer Grimsley dominated the stage as Wotan, king of the gods. With his powerful baritone, Grimsley vividly charted the character's obsessive but increasingly uncertain lust for power. The same could be said for Nathan Berg's Alberich, the tortured troll who trades love for world domination and whose final curse was the evening's most compelling moment.

Richard Cox's Loge, fervently sung, was sly and manipulative, Katharine Goeldner was an aptly whiny Fricka, Karin Wolverton a smartly vocalized Freia and Dennis Petersen a pathetically put-upon Mime. Julian Close and Jeremy Galyon were the impressive Giants, actually scary figures rather than buffoons. Denyce Graves was a commanding, deep-voiced Erda. Kyle Albertson and Christopher Colmenero were the eager gods Donner and Froh. Mary Evelyn Hangley, Alexandra Razskazoff and Nadia Fayad were the saucy Rhinemaidens.

Leading the orchestra, Christie sustained tension and clarity throughout the non-stop two-and-a-half-hour course of the opera and drew polished playing from the musicians. As we've learned the past 31 years, however, the sound orchestras make on the Ordway stage lacks resonance. That's why the St. Paul Chamber Orchestra finally bailed out and built its own hall next door.

Nonetheless, a good, though in this case somewhat compromised "Rheingold" is no small achievement. This is, after all, the dullest — certainly the talkiest — of the "Ring" operas. But why do it if the facility — chiefly the small orchestra pit — is inadequate?

One answer: the Wagner operas, for some reason, are rarely done here and apparently never have been. This company staged "The Flying Dutchman" many seasons back, and in 1988, Edo de Waart — the flying Dutchman himself — conducted the Minnesota Orchestra in a concert version of "Das Rheingold."

So who knows? Maybe Minnesota Opera has made the first step — its big toe dipped carefully into the Rhine — toward future "Ring" cycles. Perhaps the pit can be enlarged.

Michael Anthony is a Twin Cities classical music critic.