The world of renewable energy accomplished a monumental feat. Solar Impulse 2, a solar-powered aeroplane became the first manned plane of its kind that successfully completed round-the-world flight. The final stretch of its 23 days long journey in the air ended at the place where it all began, Abu Dhabi on Tuesday 26 July. A plane powered only by sun, requiring no fossil fuel, able to tour the globe may sound a bit like science fiction, but two Swiss pilots, Bertrand Piccard and André Borschberg done the imaginable.