[Retric]

You can buy solar powered electrified boats, even with solar they have short ranges and low speeds. Fine for a pleasure trip but not even close to enough for say a tugboat.

The extreme end is icebreakers which actually sometimes use nuclear power because even fossil fuels have energy density issues. Not that we need to replace nuclear icebreakers, but many countries use the non nuclear version, and when you start talking ~100MW * weeks the batteries needed get crazy.