The endgame for container ships is probably synthetic fuel produced with excess renewable power. Large container ships already only release like 100g of carbon per ton of freight per kilometer traveled. It’s ~2tins of co2 to get a ton of freight across the pacific, which is like 11k kilometers.

Ideally synthetic fuel will be carbon neutral because it’s made from ammonia derived from green hydrogen. Analysts expect it to account for ~15% of marine fuel in 20 years…