This article gives a little bit more detail: http://newatlas.com/autonomous-electric-shipping-container-v...

The article says they're using this to replace an overland truck route between Porsgrunn and Larvik, Norway - roughly 25km. I'd guess the shipping route is double that?

That's an awfully short route to use a ship on. I could see this being very useful for stuff like vehicle and passenger ferry transport but cargo containers seems downright ridiculous.

Their previous process was load container on truck, drive to major port, unload container from truck, load container onto a ship. The plant apparently is a small port, so the new process is load container on ship, sail ship to major port, unload container from ship, load container onto another ship. I don't see why loading and unloading a ship would be more onerous than loading and unloading a bunch of trucks. So if the ship uses less fuel than a bunch of trucks, it's a win. Why not do it?

Siemens [1] recently put an all electric propulsion, battery powered ferry into operation on the Lavik-Oppedal route in Norway. So not exactly long haul, but a good demonstration on the feasibility of the technology.

Hurtigruten [2] has ordered new hybrid ships that will be able to run all electric for shorter periods of time in normal cruise speeds, while operating for much longer times in fjords on slower speeds.

[1] https://www.siemens.com/press/en/pressrelease/?press=/en/pre...

[2] https://www.hurtigruten.com/about-us/news/new-hybrid-explore...

The closest one Brevik is about 11km by car so maybe 15km by sea and Larvik is 29km by car but around a jut of land so closer to 50-75km by sea. So over all fairly close together.