To remain competitive, shipping will need to re-tank to burn tropically synthesized (most likely) anhydrous ammonia, which will soon be cheaper even than bunker oil. Ships still burning oil will find increasingly fewer ports open to them.

The west-African coastal Sahara, coastal Peru/Bolivia, Baja California, Arabia/Sudan/Eritrea, Yemen/Oman/Pakistan, Socotra, and north-western Australia all look like good places to site solar-driven ammonia synthesis. I don't doubt that less geographically-favored sites will dominate instead.