The global container shipping industry, with 7,000 vessels moving three-quarters of global trade, remains heavily reliant on fossil fuels and accounts for about 3% of annual greenhouse gas emissions. Unlike land-based transport, ships cannot plug into cleaner grids, necessitating alternative fuels. Ammonia and methanol, produced via renewable-powered electrolysis of hydrogen, offer carbon-free options with energy densities similar to fossil fuels, allowing use in existing engines with minimal modification.

However, cost remains the primary barrier: green ammonia has historically ranged from $600 to $1,050 per tonne, compared to $500–$600 for heavy fuel oil. Analysts suggest long-term offtake agreements could lower prices, but scale and investment are lacking. Experts like David Fishman of the Lantau Group emphasize that cost reduction depends on scaling production and gaining operational experience, not new chemistry.

Regulation, carbon pricing, and incentives are seen as essential to drive adoption, as efficiency gains alone cannot offset rising emissions from expanding trade.