Currently, ships contribute about 2-3% of all global greenhouse (GHG) emissions—more than Germany’s entire annual emissions and thus making shipping the 6th largest emitter worldwide. Over the next 30 years, international maritime transport seeks to reduce its GHG emissions by at least 50%. Full decarbonization, meaning zero-emission vessels across all oceans, is to be reached as quickly as possible within this century. This is what the International Maritime Organization (IMO) has committed to in its initial strategy on the reduction of GHG emissions from ships.