The honest answer is that this is one of the edge cases that will probably electrified late. There are of course a lot of other use cases where electrification is a lot easier and more doable (e.g. tug boats are already being electrified).
There are probably a few practical ways it could be done economically. One simple way that comes to mind is to use battery ships that connect to the main ship via cables. Those could move back and forth between charging spots and act as a mobile power supply. The question then becomes how much battery can be fitted on these ships and the practicalities of connecting ships with cables. 1mwh is about ~4 tonnes at current energy densities. Small barges commonly carry hundreds of tonnes of freight.
Another obvious one is using small nuclear reactors. Not a popular solution with environmentalists but doable technically.
Bio fuels are an alternative to fossil fuels. In the same way hydrogen or derived fuels are a valid alternative. More expensive than fossil fuels, but it would work.
And if you apply system thinking here, a valid question is whether using more but smaller ships could work. People are getting hung up on electrifying the same huge ship. The only reason that huge ship is economical is the economies of scale you get with large engines and relatively expensive fossil fuels.
As the article notes, dredging is something that used to be done manually and assisted by wind power. So, it can be done. It's just a lot more labor intensive that way. But we have ways to make these more autonomous now. So, an army of smaller battery operated dredge robots might replace a big dredging ship. They'd be moving back and forth between charge points and where the action is.
It all boils down to cost, economics, and practicalities.
There are probably a few practical ways it could be done economically. One simple way that comes to mind is to use battery ships that connect to the main ship via cables. Those could move back and forth between charging spots and act as a mobile power supply. The question then becomes how much battery can be fitted on these ships and the practicalities of connecting ships with cables. 1mwh is about ~4 tonnes at current energy densities. Small barges commonly carry hundreds of tonnes of freight.
Another obvious one is using small nuclear reactors. Not a popular solution with environmentalists but doable technically.
Bio fuels are an alternative to fossil fuels. In the same way hydrogen or derived fuels are a valid alternative. More expensive than fossil fuels, but it would work.
And if you apply system thinking here, a valid question is whether using more but smaller ships could work. People are getting hung up on electrifying the same huge ship. The only reason that huge ship is economical is the economies of scale you get with large engines and relatively expensive fossil fuels.
As the article notes, dredging is something that used to be done manually and assisted by wind power. So, it can be done. It's just a lot more labor intensive that way. But we have ways to make these more autonomous now. So, an army of smaller battery operated dredge robots might replace a big dredging ship. They'd be moving back and forth between charge points and where the action is.
It all boils down to cost, economics, and practicalities.