I think as battery technology keeps getting better. Building batteries in the shape of 40 foot or 20 foot shipping containers would be the way to go. Container ships can then replace battery containers on every port call just like they do the shipping containers. As worldwide we already have networks for the movement and storage of these containers the cost of implementing this system would not be very high apart from the charging stations for the containers but that would be another source for revenue for the ports.

Here's a real engineering youtube video about this!

https://www.youtube.com/watch?v=WWiX2edcBoA

> So some people in the naval industry propose going back to using wind power, either via traditional sailing or more elaborate schemes (via electricity generation as an intermediary).

I've seen proposals to use wind power as an auxiliary source. I have yet to see serious proposals to convert to solely wind power.

Couldn't you use the rocking of the boat as a means to generate electricity? Seems maybe easier than wind, which I can only imagine as putting some type of turbine on the deck, except in calm seas where you would need to make sure you had enough battery capacity.