* Polls show strong support for Greens weeks before vote
* Greens open to coalitions with right and left
* Son of Turkish immigrants new face of party
By Sarah Marsh
STUTTGART, Germany, Sept 10 With a charismatic new leader and a more moderate profile, Germany's Greens are riding a wave of support for ecological policies that could turn them into kingmakers after the federal election on Sept. 27.
In nationwide opinion polls, the Greens have risen to record highs of around 13 percent, just behind the business-friendly Free Democrats (FDP), the favoured coalition partner of Chancellor Angela Merkel's conservatives.
If they manage to leapfrog the FDP on election day, Merkel may seek to partner with the Greens instead, preferring them to another awkward "grand coalition" with the centre-left Social Democrats (SPD).
The SPD could also try to woo them into a three-way coalition with the FDP, potentially giving the Greens enormous influence over the shape of Germany's next government.
Were they to get into power, the Greens say they would foster the development of renewable energies, seek educational reform and push through the controversial planned phase out of nuclear energy by 2020.
Given their pacifist ideals, they may also make Germany more cautious about engaging in foreign combat missions and could raise pressure for a cut in German troop levels in Afghanistan.
"The Greens are a party at the centre of the political spectrum, open to coalitions with parties on both sides," said Peter Loesche, emeritus professor of political science at Goettingen University.
This is a dramatic shift for a party which once condemned Germany's conservative parties for being what they called handmaidens of an imperialistic U.S. nuclear arms buildup.
The conservatives, for their part, used to revile the Greens as dangerous militants when they first entered parliament in the 1980s wearing jeans, woolly sweaters and brandishing potted plants.
Times have changed. The Greens have traded in their image as tree-hugging hippies for a more moderate profile and after a first taste of government in coalition with the SPD from 1998 to 2005, they are eager to regain a foothold in power.
Since last year, they have ruled in the northern city-state of Hamburg in coalition with Merkel's Christian Democrats (CDU), providing a blueprint for an alliance at the federal level despite lingering differences over economic policy, security and nuclear power.
At the forefront of the Greens transformation is Cem Oezdemir, 43, the first new face to appear in the party's ageing executive since the departure of long-time leader and former foreign minister Joschka Fischer.
The son of Turkish immigrants, he is also the only member of an ethnic minority to have ever headed a German party.
With his trademark sideburns and dapper attire, Oezdemir embodies the new slicker image that the Greens are keen to showcase. He stresses repeatedly that "green" policies can be business friendly and a motor for growth as Germany tries to emerge from its deepest recession since World War Two.
"Environmental policies create jobs, they don't threaten them," Oezdemir told Reuters before taking the stage at a campaign rally in Stuttgart where he was cheered by hundreds of young supporters in an old brick factory.
The Greens were the strongest party in local elections last June in Stuttgart, and supporters around town wear t-shirts emblazoned with the word-play "CEMpion".
Support has risen as environmental concerns have become more mainstream and gained legitimacy.
Although other parties, including Merkel's CDU have jumped on the climate bandwagon, analysts say the Greens are still viewed as the experts.
Core support for the party can be traced back to its roots in the anti-nuclear and peace movements of the 1970s.
A wide majority of Germans still oppose atomic energy -- an issue which sharply divides the country's left and right. Some 50,000 activists took part in an anti-nuclear rally in Berlin last weekend to highlight the topic before the federal vote.
"I've voted for the Greens ever since they existed," said Beate Illert, 55, speaking in front of a Greens information stand in Stuttgart. "I studied chemistry at university and their stance on atomic energy is extremely important to me."
As junior coalition partners with the SPD, they turned a long list of environmental causes into law, for example forcing power companies to phase out nuclear energy. They also helped Germany become a world leader in renewable energy -- a position the Greens are not ready to give up without a fight.
"In the past four years we almost lost our role as pioneers of renewable energy technology," said Renate Kuenast, one of the party's leading politicians, at the campaign rally in Stuttgart. "This time must come to an end, and you can do it by voting Green on Sept. 27." (Editing by Noah Barkin and Myra MacDonald)