The invention relates to an energy system for watercraft, comprising at least one fuel cell module (6,7,8,9), preferably (a H.sub.2O.sub.2 fuel cell module, by which at least one electric drive (17) and at least one electrical consumer are supplied with electric energy via a supply network. Said electrical drive (17) is an AC drive that is connected to a DC network (2) of the supply network via at least one power inverter (10).