* Anti-nuclear party soars after Japan disaster
* Historic victory for Greens over Merkel's CDU
By Erik Kirschbaum
BERLIN, March 27 (Reuters) - Japan's nuclear disaster helped lift Germany's anti-nuclear Greens off the opposition benches and into the seat of power of the country's richest state on Sunday with an unprecedented surge of popularity.
In a stunning victory, the Greens ousted Chancellor Angela Merkel's party in the industrial state of Baden-Wuerttemberg, which the conservatives have ruled for 58 consecutive years. The Greens also beat their traditional allies, the Social Democrats.
"This is a historic turning point in Greens history," said party co-leader Claudia Roth at celebrations in Berlin after an ear-splitting cheer went out at 6 p.m. as exit polls showed the Greens had enough support to win the state premier's office.
Founded 31 years ago as a colourful band of peaceniks and anti-nuclear activists, the Greens made their mark mostly as an entertaining opposition party. Their trademarks included muesli, woolly sweaters, long hair, thick beards and gender equality.
They were long wracked by rows between a fundamentalist wing -- "fundis" who wanted to stay in opposition, and more pragmatic "realos" who sought to influence policies and get into power.
The "realos" ultimately won the upper hand after about 20 years and the Greens took power as junior partners to the centre-left Social Democrats at the national level in 1998.
Joschka Fischer, a prominent "realo" who had begun his political life as a leftist street radical in the late 1960s, served as foreign minister in that government.
Over the next seven years, the SPD-Greens government gave Germany vibrant renewable energy laws that have helped the country become a world leader in wind and solar power -- which is now responsible for 17 percent of its electricity.
They also wrote a law to scrap nuclear power by 2022.