I don’t doubt that it’s a lot, but can anyone provide a source for the 40% of global ship traffic? I couldn’t find any statistics sadly

The data is from UNCTAD

Small clarification. My understanding is that it’s 40% by weight of goods carried, not 40% of ships. So still massive chunk, but not quite the same metric. Also some of those ships would still presumably be messed to move batteries and solar panels, At least for a while until we have enough for a closed loop recycling system (we can recycle like 99% of the lithium from lithium batteries, no idea how emerging sodium batteries will affect things)

Do you happen to know how battery or fuel cell ships are doing atm?

There are some, but afaik they weren’t ready for global shipment yet, but more local, due to range.

If you want green cargo shipping, it might be better to look to the past. Way back in the day, all shipping was very green, powered by wind. Maybe we could have a return of sailing ships?

Though, of course, sails do have some big disadvantages, which is why they were replaced in the first place. You’d definitely want an electric (or even fossil fuel) powertrain available to use as a backup or in emergencies. But when winds are favorable, why not set sail and let very green wind energy propel you across the ocean? As an extra bonus, sails are cheap and a very mature, well-understood technology. All you need to do is scale them up.

The biggest difference at the end of the day is that sailing ships are generally slower and require much more crew. So overseas shipping would be slower and possibly more expensive. (Though the massive fuel savings might offset the expense somewhat?) But I don’t necessarily think that slower and more expensive overseas shipping would be such a bad thing in the long run. It would encourage more local production and consumption.

Going back to sails is a cool idea, but I don’t see how it’s viable, nor will batteries be. We’re going to need to settle on some sort of sustainable liquid fuel for a few uses like shipping and aviation.

Maybe this is even some good that can be driven by militaries

but I don’t see how it’s viable

It was viable enough in the 1800s.

for a few uses like shipping and aviation

Yeah … aviation in particular will probably be mainly fossil fuels for a long time to come, because it really needs energy density.

The solution there is just for people to fly less. (Which could be partially accomplished by having fast electric train routes.)

It was viable in the 1800s because it was the best method available. We don’t use it today because it ultimately costs more. A wind-powered company would have to compete against others using extremely energy-dense fuels that enable hundreds of times more cargo (between increased speed and increased capacity) for the same time and money.

So, in other words, it’s perfectly viable … just not economically viable.

That’s a failure of our economy, not of the technology. Perhaps if all the externalities of fossil fuel emissions were included in the cost of fossil fuel shipping (say, with massive taxes on fossil fuels to fund environmental efforts and carbon capture), that would change the balance.