Supplying energy to the global shipping fleet is not a marginal challenge but a question of scale. Commercial vessels operate continuously, often for weeks at a time, generating propulsion and onboard power far from shore-based infrastructure. Few industries place such sustained demands on their energy systems.
This reality stems directly from shipping’s role in global trade. More than 80% of goods traded worldwide are transported by sea, amounting to close to 11 billion tons of cargo each year. By 2030, annual volumes are expected to reach around 16 billion tons. Supporting this activity is a global fleet of roughly 105,000 vessels, forming an industry worth approximately $14 trillion. Larger ships and containerization have driven efficiency and lowered costs, but they have also entrenched the need for large, continuous energy supply.
Meeting that demand requires vast amounts of fuel. Each year, the global fleet consumes approximately 250 million tons of fossil fuel, equivalent to around 2,750 terawatt hours (TWh) of energy. This demand is continuous and unavoidable. Ships must generate power regardless of location or distance from infrastructure, and as trade expands, energy demand rises in step.
The maritime sector operates at a scale that places uniquely demanding requirements on energy solutions. Space onboard is limited, refueling opportunities are infrequent and vessels must perform predictably over long distances. Energy systems must therefore deliver high power density, continuous output and global scalability as operational necessities. Nuclear is that solution!
Conventional bunker fuel has historically met these needs because it is energy dense, straightforward to store and widely available. Replacing it is not simply a matter of substitution. While efficiency improvements can reduce fuel use incrementally, they do not alter the underlying physics of moving large volumes of cargo across oceans. Scale remains the defining constraint.
Understanding shipping’s energy challenge in these terms broadens the discussion to include infrastructure, physics and economics alongside environmental and regulatory considerations. As shipping activity continues to grow, the central question becomes how energy can be supplied at the scale required without compromising reliability or affordability.
Nuclear energy is designed to operate continuously and at scale and already provides around 10% of global electricity. Nuclear has the highest capacity factor of any major energy source and plants typically operating close to full output for the majority of the time. Combined with the exceptionally high energy density of nuclear fuel and a relatively small physical footprint, this makes nuclear well suited to meeting the reliability, power density and scalability requirements of maritime energy systems. Advances in nuclear technology are further strengthening this alignment by improving efficiency, flexibility and suitability for a wider range of deployment scenarios.
As questions surrounding alternative fuel sources to conventional bunker fuel gain prominence, so do considerations around ship design and regulation. Next week, the International Maritime Organization’s Sub-Committee on Ship Design and Construction (SDC 12) will meet to consider technical and safety matters related to vessel design, including the revision of SOLAS Chapter VIII, which sets out safety requirements for nuclear-powered ships. The session includes discussion of the Code of Safety for Nuclear Merchant Ships, which has not been updated since its adoption in 1981, and reflects efforts to modernise the regulatory framework for civil nuclear propulsion in shipping. SDC 12 will also consider the need for intergovernmental cooperation and progress towards a more globally harmonized approach to liability.
For an industry defined by scale, energy solutions must be conceived with that same scale firmly in mind.
