Michael Lang said plans for a 40th anniversary Woodstock concert are "all speculative ideas" for now, but he hopes to bring them to reality this summer.

The Woodstock co-founder told Billboard.biz that his vision is "a free event...a very green project," possibly in New York City. "We want to have as small a carbon imprint as we can and use as many green techniques as we can," said Lang, who was in Austin as part of a South By Southwest panel discussion about Woodstock. The holdup? "It's got to be sponsor-driven," he explained.

"It's free, but it costs a lot of money. That's kind of what we're in the middle of right now. Depending on how successful we are in raising that sponsorship (money) will determine when and how we do this event – or if we do this event, frankly."

He added that reports of a concurrent Woodstock festival in Berlin, possibly at Tempelhof airport, were "premature" but "still is kind of a thought."

Lang said that musically a 2009 Woodstock would go "back to its roots...There would be a lot of legacy bands – the Who, Santana, Crosby, Stills & Nash, Joe Cocker maybe. And it would be people like Steve Earle and Ben Harper. There's certainly room for the (Red Hot) Chili Peppers and Dave Matthews...That would be the shape of the music."

The Red Hot Chili Peppers, of course, closed the ill-fated 30th anniversary concert in 1999, which was marred by complaints about the facilities, food and water prices and ended with a fiery riot. But Lang said he was confident that the Woodstock brand was not permanently damaged.

"I think it always hearkens back to the '69 event, somehow," he said. "When people think [of Woodstock] they don't think '99 or '94. They think [of] the '69 event. I think [1999] has its ramifications, but I don't think it did any real damage in that sense."

With or without concerts, Woodstock's 40th will be celebrated with an array of projects this year. Lang has written a book in collaboration with Holly George-Warren that will be published in August. He's also working on a VH1 documentary with Barbara Koppel.

On June 9, meanwhile, Warner Home Video will release a four hour director's cut of the "Woodstock: 3 Days of Peace and Music" film featuring 18 new performances – including some from five groups (Creedence Clearwater Revival, the Grateful Dead, Johnny Winter, Mountain and the Paul Butterfield Blues Band) that did not appear in the original film. Rhino Recods will roll out new albums of Woodstock performances.

Director Ang Lee has made "Taking Woodstock," a feature film about the real estate agent who helped the 1969 festival move to Bethel, N.Y., after losing permission to hold it in nearby Walkill.