International shipping is indispensable for global prosperity and trade - in 2015, 70% of the world's tonne-kilometres were transported by ship, and a sharp increase by a factor of 3.5 is expected by 2050. In view of 2045 net-zero goals and, at the same time, the very long operational lives of ocean-going vessels, sustainable concepts and fuels are urgently needed. Promising candidates in ocean shipping are ammonia, methanol and synthetic methane as bridging technologies. Hydrogen and direct electrification appear to make more sense in near-coastal shipping.
