(CNN) Nico Rosberg's current life is a world away from the career he enjoyed as a Formula One world champion, piloting gas-guzzling race cars to victory at circuits around the world.

The German has transformed not only his professional lifestyle but his personal one, too, promoting a sustainable future with the help of his latest venture.

In Berlin, the site of this weekend's E-Prix, Rosberg has returned with his Greentech Festival, a platform for green companies from around the world to showcase the renewable technology of the future.

Since its inception five years ago, Formula E has been at the forefront of promoting the possibilities of green travel in a fun and exciting way.

Some of the world's most prestigious manufacturers have already joined the rapidly-growing series, with one more big name set to be thrown into an already thrilling mix from next season in the shape of Mercedes.

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