Das Rheingold, Royal Opera House, London

It is with the lowest sonorities and the highest expectations that any major opera house embarks on a new Ring cycle. String basses sound their profoundest E flat, bassoons add a B flat, and with that immovable two-note chord, Wagner first plumbs the depths of the Rhine while, one after another, eight horns fold his magical Rhine motif into the texture. And with it, a glimmer of light.

We see that light - the Rhine gold - a pinprick in the darkness, at the start of Keith Warner's new Royal Opera staging. It hovers elusively, temptingly, something just out of reach for us all. So far, so simple. Would that what follows were, too.

But the truth is that Warner's Ring will need to shed a great deal of excess baggage as it proceeds on its momentous journey. There were moments during this opening instalment when it threatened to sink back to where it began 14 hours ahead of schedule. Wagner both embraced and transcended technology, but Warner is somewhat hampered by it.

Stefanos Lazaridis is his designer. Right from the outset, when Alberich arrives by boat down a spiralling track redolent of something from Disneyland, we ask ourselves if the means justifies the end. Not here, it doesn't. But then, later in that scene, director and designer give us something really breathtaking when the swirling waters of the Rhine seem to coalesce into a projection of a spinning globe: the ultimate prize for those with power and ambition.

Wotan appears right on cue here, a primitive, mythical form in animal furs, with rough-hewn spear. Underneath, he wears full evening dress. His des res - Valhalla Towers - is a fabulous black, marble-lined penthouse, high above the clouds, with vast windows on the world. The gods are on the inside, looking out. The giants who built it are on the outside, looking in. They arrive, as is appropriate for artisans, by ladder.

And, oddly, Alberich's magic helmet, the Tarnhelm, bears more than a passing resemblance to the gods' high-security fortress. Dreams and the realisation of them are key factors in Warner's staging, but he's going to have to keep his designer on a tighter rein.

Probably the most effective aspect of Warner's staging thus far is his depiction of character. At the heart of the Ring - when you strip it right back to its bare essentials - is human nature. The relationship between Wotan and Loge, his dubious adviser, is striking here. Bryn Terfel's vocally sensational Wotan is a commanding captain of industry with a notably short fuse. He doesn't suffer fools gladly. He doesn't suffer them at all.

During the scene in Nibelheim - which Warner and Lazaridis play out as a dubious research laboratory where humans as opposed to animals are the new age of guinea pigs - Wotan loses his temper, while Loge uses his head. Philip Langridge - bespectacled, with bald head and red pigtail - plays him with uncustomary edge. He's no longer just the joker in the pack, but a wily Mr Fixit with a conspicuously mean streak. This god of fire is actually a bit of a pyromaniac, who liberates Alberich's put-upon brother Mime (the excellent Gerhard Siegel) by threatening to set him alight. While the gods contemplate Valhalla, he's contemplating his next flambé.

The casting of this Rheingold is generally strong at all levels. A German Alberich is always an asset, and Günter von Kannen plays the text terrifically well. Vocally he's less impressive, but with Terfel close at hand through most of the opera, everyone tends to be shown up vocally - certainly Mrs Wotan (Rosalind Plowright's Fricka), though physically she cuts an imperiously domestic figure.

There's another seasoned and marvellous performance from Jane Henschel as the earth goddess Erda. And, as Antonio Pappano and his magnificent orchestra process us across the rainbow bridge, Wotan is seen bearing down on her to sire the Valkyries... same place, next year in Der Ring.

To 10 January (020-7304 4000)