This is all about utilizing efficient grid power (hydro, nuclear, gas, whatever) on a ship. By grid-intertie at the ship level, re-fit costs are minimized. Kinda like rooftop solar.
The possible few percantage difference in efficiency between ship-based oil-powered generation, and land-based power generation, is more than wiped out by the storage and conversion losses of a battery-based system. It's also very expensive (and heavy). Why pay to fill a container with batteries, and then pay more to charge them, when you can be paid to carry a container of other stuff as cargo?
https://data.worldbank.org/indicator/EG.ELC.PETR.ZS
Oil’s benefit is its density, storability and pumpability.
All I know is that a giant ship is the most cost-effective way to transport anything heavy by vehicle.
A few percent improved efficiency in exchange for losing a handful of container capacity on a ship carrying several thousand is a net positive. And cargo shipping is a tight business.
Battery storage and conversion losses are far less than the conversion losses from generating electricity from an ICE.
No, they are not. Here's some research for large-scale battery storage systems:
https://www.osti.gov/servlets/purl/1409737 Rround-trip energy storage efficiency is reported as 70% - 80%. Any crappy genset will match that.
I really don't understand this idea for a "hybrid" ship. What size battery would you need, to power the electricals of a ship for a sea voyage? What is the payback period to the shipping company?
I think you meant "most".
The least efficient step is converting chemical energy into mechanical energy.
Given the cheapness of fuel oil and geneator sets, and the expense of batteries, what possible financial argument is there for doing this?