If you have solar paired with proton exchange membrane electrolysis, you can generate hydrogen very economically. PEM electrolyzers are already around 80% efficient but supply is limited right now. Hydrogen is a pain to store, but if you feed that hydrogen into the Haber-Bosch process you can very efficiently produce ammonia. Ammonia fuel cells are very promising if you’re looking to decarbonize container shipping.
It’s for the Korean market. It’ll get you from Seoul to the east coast on a single charge and there’s high-speed rail just about everywhere for your longer journeys. Perfectly fine for most people in such a small, densely-populated country.