PARIS (AP) — A boat that fuels itself is setting off around the world from Paris on a six-year journey that its designers hope will serves as a model for emissions-free energy networks of the future.

Energy Observer will use its solar panels, wind turbines and a hydrogen fuel cell system to power its trip. The 5 million-euro ($5.25 million) boat heads off Saturday from Paris toward the Atlantic.

The futuristic-looking 30.5-meter (100-foot) boat will rely on sun or wind during the day and tap into its hydrogen reservoirs at night. It produces its own hydrogen through electrolysis of sea water....