It’s not stage-filling spectacle, but Barrie Kosky’s version of Wagner’s “Das Rheingold,” the start of a four-opera epic, is eerie, vivid and intense.Two years ago, the Metropolitan Opera went shopping for a new “Ring” in London and came home empty-handed.English National Opera’s first installment of Wagner’s four-part epic of gods and humans, lust and power, was judged a bit too scrappy and bare to transfer to the grand Met. And anyway, the English company was soon reeling from cuts to its government funding, putting the completion of the cycle in jeopardy.The Met would like to bring a “Ring” to New York in four seasons — a blink of an eye given opera’s glacial planning cycles and Wagner’s technical and casting complexities. So its leadership has another London option under consideration: a production directed by Barrie Kosky that opened on Monday at the Royal Opera, the city’s bigger and older company.Eerie, vivid and intense, Kosky’s version of “Das Rheingold,” the first “Ring” opera, is a show that an opera house on either side of the Atlantic could be proud of, accessible and stimulating for Wagner newcomers and connoisseurs alike. The story is crystal clear, and its emotional and political stakes are taken seriously, without oversimplification or overstatement.It would also finally bring to the Met one of opera’s finest, most rangy and resourceful directors. (A collaboration on Prokofiev’s “Fiery Angel” was spiked during the pandemic.) Kosky, who was born in Australia, was celebrated during his recently ended tenure at the helm of the Komische Oper in Berlin, for his revivals of long-forgotten operettas and his giddy disregard for distinctions between high and low art, between “Kiss Me, Kate” and “Moses und Aron.”His signature style is zany, high-spirited and high-kicking, but he can do sober and austere when the piece calls for it, like a starkly savage “Kat’a Kabanova” at the Salzburg Festival last year. His Royal Opera “Rheingold,” though not without shots of bitter humor, is in this vein.The work’s single, two-and-a-half hour act is all played atop, around and inside a huge hollow tree trunk, collapsed on its side. This is a dying world, Kosky suggests — and to that end he puts Erda, the earth goddess who intones a climactic warning, onstage almost throughout, in the form of a silent actress: elderly, naked, frail, vulnerable. (For that climactic monologue, the singer is hidden from the audience.)Katharina Konradi with the magic gold, whose theft from the Rhine sets the “Ring” in motion.Monika RittershausThe gold whose theft from the Rhine sets the “Ring” in motion, and from which the central ring of power is forged, is here a shiny, syrupy fluid that flows from the tree. It evokes, appropriately, a union of metal and river, as well as the fossil fuels on which the global economy is disastrously based. Its associations range bodily and geologic — lava, milk, semen, blood, honey — and characters lick it greedily from their hands.Kosky and his set designer, Rufus Didwiszus, have imagined Nibelheim, the inferno in which the stolen gold is worked on, as a steampunkish industrial monstrosity, with clamps gripping the tree. Erda, her torso popping out of a knot in the trunk, is connected to tubes that pump the iridescent batter from her body and drain it into pails. This society is built from — and rotted by — the devaluation of women (particularly the old) and environmental exploitation.Victoria Behr’s costumes are contemporary, and there are hints of British flavor: These wealthy, self-serving gods have a taste for nostalgic old-money activities like polo. But this is a basically placeless, timeless production; its primary location, the theater. Kosky emphasizes this by having the audience enter, curtain up, to see the unadorned expanses around the stage. Stagehands do their work visibly, and Alessandro Carletti’s lighting draws attention to its equipment.Kosky uses steam, lights, loudspeakers and knobby holes in the tree to conjure, in charmingly old-fashioned ways, the magic effects and transformations of Wagner’s libretto. But this staging mostly lacks proscenium-filling spectacle — and it was a similar lack that made English National Opera’s “Ring” a no-go for the Met.The transitions between the scenes in “Das Rheingold,” from the heights of mountains to the bowels of the earth and back again, are played at the Royal Opera with the curtain closed, as if Kosky is thumbing his nose at expectations that he is supposed to provide more of a scenic extravaganza. Instead, those interludes are simply showcases for Antonio Pappano, starting his swan-song season as the company’s music director, and the orchestra.You could call this meager. But on Monday, it felt more like focused modesty.Christopher Purves, center, as Alberich transforms the tree into an industrial monstrosity pumping golden fluid from Rose Knox-Peebles, left, as Erda.Monika RittershausWork that’s powerful in the 2,200-seat Royal Opera House won’t necessarily make the same impact in the Met, nearly double that size. But the last New York production of the cycle, directed by Robert Lepage on a preposterously expensive, 45-ton high-tech set, was, when it opened in 2010, an artistic embarrassment for the company as well as a depressing example of empty-headed excess at a time of financial crisis.The “Ring,” given its size and prominence, is a symbol of an opera house’s values, and the lean vitality of Kosky’s vision, which will unfold in London over the coming years, seems right for an era of budget and programming cuts.At the Royal Opera, Pappano and the orchestra match Kosky with fiery but never overblown playing, especially from the lush yet biting strings, their intimacy startling. This is a “Rheingold” that, first and foremost, supports its singers.Wotan, the king of the gods, and Alberich, the dwarf who steals the gold from the Rhine, are here almost brotherly figures, both with bald heads and sturdy bodies, and they share certain qualities, too. Christopher Purves’s Alberich has aristocratic reserve, while Christopher Maltman’s booming, tight-smiling Wotan is capable of feverish aggression; it is shocking but not surprising when he cuts off Alberich’s finger to take the ring.Yet the tenderness with which Maltman embraces the fragile Erda, as the voice of the goddess is heard warning him to give up the ring, is just as indelible, and feels just as true. As Fricka, Wotan’s wife, Marina Prudenskaya sings with slicing anxiety; Sean Panikkar is a charismatically grinning, cackling playboy as Loge, the anarchic fire god; Insung Sim is unusually agonized as the giant Fasolt.This is not an ostentatious production. But the finale, which shouldn’t be given away, is proscenium-filling spectacle, and vintage Kosky, in that it uses one of theater’s simplest, most traditional devices with unforgettable showman flair, conveying all the glittering glamour and fundamental emptiness of the gods’ ascent to their new home — a triumph as hollow as the giant tree.Das RheingoldThrough Sept. 29 at the Royal Opera House, London; roh.co.uk. More