MikeAqua:

 

Coastal shipping .... I read a couple of articles on those ships.  They're a good idea.  Presumably if your battery pack catches on fire you can just push it overboard.  But .... 700 TEU is small.  Most second tier container ships are 2,000 TEU.  The big ones are over 4,000 TEU.  Some short run stuff is certainly possible, like Tauranga to Auckland.  But rail would actually be better for that as you note, and there is a rail line.  I wonder if our forebears were smart enough to leave room for cabling in the Kaimai tunnel?  

 

They may well be bigger than that now. The article I was fact-checking myself upon dates to 2023. A lot will have changed in three years, especially in China. But they are not in any way confined to the Chinese market. And it's also worth noting that the original Panamax ships were only 5000 TEU so a 4000 TEU electric coastal ship isn't far off the maximum you used to be able to sail through the Panama Canal.