When San Francisco Opera concludes its uniformly acclaimed summer production of Richard Wagner’s “Die Walküre” next week, don’t say goodbye, only au revoir — until we meet again.

That will be next summer, when the company presents three cycles of the Mount Everest of opera, Wagner’s “The Ring of the Nibelung,” over four nights in productions running June 14-July 3, 2011. The music alone runs more than 15 hours; a full cycle, with intermissions, lasts about 18 hours.

The introduction to this tale of gods, heroes, dragons, a magic fire, and the ultimate cataclysm that ends the world, is the 2¾-hour “Das Rheingold.”

The 4½-hour “Walküre” is the second opera, “Siegfried” (5 hours) the third, and “The Twilight of the Gods” (5¼ hours) is the last one.

As he has since 1990, Donald Runnicles will conduct “Ring” performances.

 The new “American ‘Ring’” production is by Francesca Zambello. The two singers making their debut here in the leading roles of “Walküre” — Mark Delavan as Wotan and Nina Stemme as Brünnhilde — will return to sing in the entire cycle.

San Francisco Opera General Director David Gockley estimates the cost of producing the “Ring” operas over three years at $23 million (part of the annual operating budget of $67 million). It’s a thrifty alternative to the Los Angeles Opera’s current $32 million-plus, and probably to the Metropolitan Opera’s planned “Ring,” for which no estimate is available (the company has a $291 million annual budget).

While exact figures aren’t available, “The Ring’s” expected audience of up to 40,000 — including thousands of out-of-town hotel guests and restaurant customers — will contribute significantly to The City’s economy.

The opera is hosting not only the “Ring,” but also a citywide celebration of the festival, involving some dozen arts organizations in symposia, exhibits, films, “Ring”-related performances and special events.

“The magnitude of the ‘Ring’ and the extraordinary legacy of Richard Wagner continues to inspire greater study and understanding for our enrichment and appreciation,” says Gockley. “I’m very proud that so many educational, community and cultural organizations have agreed to present ‘Ring’-related programs that are innovative, bold, sensitive, complex and timely.”

Among partners of the “Ring” Festival: the Commonwealth Club, Classical 102.1 KDFC, Contemporary Jewish Museum, Goethe-Institute, Mills College, Museum of Performance & Design, San Francisco State University, UC Berkeley, Stanford University, San Francisco Conservatory of Music and the Wagner Society of Northern California.

IF YOU GO

Die Walküre

Presented by San Francisco Opera

Where: War Memorial Opera House, 301 Van Ness Ave., San Francisco

When: 7 p.m. today and Wednesday

Tickets: $25 to $295

Contact: (415) 864-3330, www.sfopera.com

SF Opera’s 2011 ‘Der Ring des Nibelungen’ Festival

Where: War Memorial Opera House, 301 Van Ness Ave., SF

When: CYCLE 1: June 14 (8 p.m.); June 15 (7 p.m.); June 17 (6:30 p.m.); June 19 (1 p.m.) CYCLE 2: June 21 (8 p.m.); June 22 (7 p.m.); June 24 (6:30 p.m.); June 26 (1 p.m.) CYCLE 3: June 28 (8 p.m.); June 29 (7 p.m.); July 1 (6:30 p.m.); July 3 (1 p.m.)

Tickets: $300-$2,800 for a four-opera cycle

Contact: (415) 864-3330, www.sfopera.com