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...