Energy Observer, the first hydrogen vessel in the world which emits no greenhouse gases or fine particles was pictured sailing off the coast of the Swedish capital, Stockholm on Tuesday. /VCG Photo

The high-tech vessel will stay in central Stockholm from May 24 to June 2. It is part of a project aimed at finding new solutions for the energy transition. /VCG Photo

Powered by renewable energies and hydrogen, Energy Observer has traveled over 20,000 km within two years, with the wind propelled wings maximizing its energy autonomy. /VCG Photo

The vessel is on a global voyage starting from 2017 to 2022, with 50 countries expected to be visited along the way. /VCG Photo