That's easy to work out from the parent comment. They conclude that 16,000 tons of batteries are needed for propulsion, with a total capacity of 3GWh.

For a typical 40kton cargo ship, that leaves 24,000 tons for more batteries, for a energy cargo capacity of 4.5GWh. The average US citizen uses ~770,000 BTUs of energy per day, or 0.23MWh. This "energy cargo" of this ship would provide the entire energy needs of a city of 20k people for one day. (I am being a little unfair, by assuming that everyone uses electricity for all of their energy needs in this scenario).