No need for complicated calculations here... Back of an envelope: - The energy density of LiIon batteries (or molten salt, or liquidy nitrogen etc) is roughly

No need for complicated calculations here... Back of an envelope: - The energy density of LiIon batteries (or molten salt, or liquidy nitrogen etc) is roughly 100x smaller than that of gasoline/diesel/bunker fuel in weight terms and 40x smaller in volume terms - The efficiency of electric motors is roughly 2x that of large diesel engines So the amount of batteries needed for the same performance is 50x larger in weight and 20x larger in volume than the oil it carries (which for a big container ship is 6,000-10,000 tons I think). Which would be impractical.