I suspect shipping designers have already exhausted most options to reduce drag and power requirements, but they still require some of the worlds most powerful engines... http://www.autoblog.com/2011/07/22/worl ... orsepower/
. And that isnt for accelleration or hillclimbing !
That would be a lot of kW to keep feeding all day, so a mighty battery would be needed.
But yes, ..maybe "containerised" battery units could be used and swapped out at the same time as the cargo.
However you then need a huge supply of battery units and charger systems, at each port the vessel planned to stop at.
Logistical nightmare !
Try some "napkin number" calculations....
Assume a small ship,..only 10,000 kW power (a fraction the size of the big freighters)
And assume ..a short 24 hr passage
So, theoretically 240,000 kWh of energy required.
Best available battery energy density is approx 200Wh per kg, hence 5kg per kWh, and 200kwh per Tone
So the daily requirement of 240,000 kWh needs 1200 tons of battery
At approx 25 tons per container, that means 480 containers per day just to keep the ship moving.!
Im sure there are major errors in the above assumptions, but it does indicate the scale of the project .
EDIT.. Corrected container max capacity 25 tons for 20' unit.