I've been enjoying this article today
Over coffee on a rainy morning in Sydney, he describes his futuristic vision for renewable ammonia. When he squints, he can see, maybe 30 years down the road, Australia's coast dotted with supertankers, docked at offshore rigs. But they wouldn't be filling up with oil. Seafloor powerlines would carry renewable electricity to the rigs from wind and solar farms on shore. On board, one device would use the electricity to desalinate seawater and pass the fresh water to electrolyzers to produce hydrogen. Another device would filter nitrogen from the sky. Reverse fuel cells would knit the two together into ammonia for loading on the tankers—a bounty of energy from the sun, air, and sea.
You could take it further, maybe the deliveries are carried out by autonomous sailboats: