SAN FRANCISCO – In this loveliest of West Coast cities, the San Francisco Opera has staged what is arguably the most intriguing production of Wagner’s Ring that one can currently see in America. On four separate nights during a week in June at San Francisco’s War Memorial House, I had the chance to witness Francesca Zambello’s brilliant new version of the composer’s four-opera tetralogy – and I must say it was a considerably more satisfying experience than either of the first two installments of the Metropolitan Opera’s new $16 million Ring by director Robert LePage.

Zambello has said she was “inspired by America” for her populist Ring – the 14 performances this summer sold to 99.96 percent of capacity and grossed more than $7 million – and we see signs of this everywhere in Michael Yeargan’s often whimsical set designs, from the Gold Rush setting of Das Rhinegold to the 20^th-century versions of Die Walküre and Siegfried (the latter complete with trailer park) and the cold, bleakly futuristic Götterdämmerung. This Ring is about “the destruction of our environment, and of our world,” Zambello said in a panel discussion during the first full run of the cycle, and this idea is borne out in both the barren industrial landscapes and in the gradual dissolution of moral compass throughout the four operas. “It’s a masterpiece because it’s contemporary,” she added.

The standout in the production was the Swedish soprano Nina Stemme in the role of Brünnhilde, possibly the most demanding of all operatic roles, which she sang with uncommon power, subtlety and vocal splendor, not to mention stamina: She sounded as fresh at the end of the 15-hour spectacle as she had in Die Walküre. She stood serious ground, a worthy foil to her father Wotan and a heroic figure that a Siegfried could truly love. Stemme is clearly destined to become one of the Brünnhildes of our generation. Somewhat less satisfying was Mark Delavan’s Wotan, which he sang with a marvelous upper register, at times finding himself drowned out by the orchestra otherwise. His acting was quite impressive, though – he could be loving father, imperious Zeus-like figure, or humbled, hen-pecked husband, depending on the demands of the moment – and for the most part made up for the sense that he was perhaps not quite ready vocally for this most challenging of male roles.

The cast for Das Rhinegold was otherwise quite strong, from the tragic, pitiful Alberich of Gordon Hawkins to the spiky vocalism of Stefan Margita as Loge. The three Rhinemaidens – Stacey Tappan, Lauren McNeese and Renée Tatum – perhaps made too much of their good-natured abuse of Alberich, but they sang with savvy blend. Elizabeth Bishop was a strong Fricka, delivering the role with authority and vocal care, though Melissa Citro’s Freia lacked control and heft. David Cangelosi is well known for his Mime, but here he seemed to exaggerate the vicissitudes of both acting and vocal line. Andrea Silvestrelli and Daniel Sumegi as Fasolt and Fafner looked scary in their rustic “giant” costumes, complete with huge boots and overalls, and sang with muscle. Erda, who rose rather unsurprisingly from a trap door, was sung with dark sympathy by Ronnita Miller, and Valhalla turned to rainbow colors as the gods exited somewhat unceremoniously on a long staircase lowered from stage left.

Die Walküre began with effective use of the projections that throughout the week became a signature part of the production – in this case a depiction of Siegmund stumbling frantically through the woods. Hunding’s hut was a contemporary bungalow, complete with screen door and Bavarian hunting-lodge décor. Brandon Janovich was back, this time as Siegmund (he sang Froh in Rhinegold), which he delivered with pleasing tone but a tendency not to “dig in.” Anja Kampe’s Sieglinde was beautifully controlled, both vocally and in her initial caution with Siegmund. A full moon blessed their lovemaking, as the fireplace glowed, and their “Winterstürme” duet was accompanied gorgeously by the crack orchestra in the pit. Sumegi sang Hunding, the jealous and murderous husband, in suitably stentorian, authoritarian tones. Delavan was more on his game here, lending Wotan a new kind of imperious grace. For the famous “Ride of the Valkyries,” the daughters of Wotan parachuted in, as if landing for battle in some 20^th-century war; we weren’t quite clear on how Brünnhilde arrived, however. Again the orchestra lent visceral excitement to this music, led by former SF Opera music director Donald Runnicles, who throughout the week proved himself one of the great Wagner conductors of our time.

Siegfried was set in a world of refineries and smog, with Mime’s hut a small trailer and the “fire” on which he forges Siegmund’s sword a sort of barbecue grill. This installment of the opera was as close to contemporary America as we come, with the dragon-like Fafner transformed into, well, a Transformer  – a giant robotic metal heap that was as threatening as it was enigmatic.Siegfried tends to ride on the strength of the tenor in the title role, and Jay Hunter Morris’ vocal performance was not unpleasant – it’s just that his tender voice is small, more lyric than heroic, and as a result Siegfried felt rather like a lightweight. Hawkins was still commanding as Alberich, however, and Delavan seemed to have gained confidence in the bizarre role of the Wanderer (who is actually Wotan incognito). Stacey Tappan sang the Forest Bird with crystalline clarity. Things lit up in Act 3 when Siegfried woke Brünnhilde from her enchanted slumber – surrounded by real fire, which only the most heroic lover would brave – as Morris and Stemme immediately forged a genuinely convincing stage romance.

Zambello’s Götterdämmerung brought the cycle to a wonderfully satisfying conclusion. This five-and-a-half-hour extravaganza has everything: Sex, humiliation, love, greed, ambition, moral degradation, impending doom. It opened perilously, with the mythic Norns – Ronnita Miller, Daveda Karanas and Heidi Melton – weaving the rope of fate (in this version they are cables being strung on the grid of some futuristic power plant) and predicting the fall of the gods. The sleek, sterile living room of the Gibichungs confirmed our sense of things unraveling, as they plotted to give Siegfried a love-potion so that he’d (a) fall out of love with Brünnhilde, (b) divert her to Gunther and (c) steal the ring. That is exactly what happens, in a scene that feels more like fairy-tale than anything since Das Rhinegold. Silvestrelli’s big, wooden voice, which we’d heard earlier as Fasolt, was perfect for the thuggish Hagen. Brünnhilde looked frightful in her frumpy wedding dress and long black gloves – she is to wed Gunther against her will – and Stemme played the scene with gripping force. Siegfried was sung here by Ian Storey, whose more substantial, heroic tenor seemed apt for the mature Siegfried, despite the fact that on the day I heard it he lost his voice during Act 2, regaining it only partly for Act 3. Gerd Grochowski was a potent Gunther, though Melissa Citro was again a bit hooty in the role of Gutrune.

The last act was a tour de force, with the Rhinemaidens returning to express dismay over the fate of the gods – wandering in a dry creek bed littered with empty water bottles.  There were moments of hokeyness – Gunther is smothered with a yellow plastic trash bag – but Stemme steals the final scene with one of the most effective, vocally rich “Immolation Scenes” I’ve seen or heard. Valhalla falls, but instead of DeMille-like grandeur we get a shower of images of dead soldiers, and a final rather baffling scene of a child planting a tree. None of this killed the effectiveness of the performance, though, which was underscored by splendid playing in the pit throughout. Runnicles was so enthusiastic about his orchestra that he brought the entire ensemble onstage to join the large cast for a well-earned ovation.

To reach Paul Horsley, performing arts editor of The Independent, send email to phorsley@sbcglobal.net or find him on Facebook (paul.horsley.501) or Twitter (@phorsleycritic).