White paper sees conversions of small LNG carriers as the quickest way to add capacity. Image Credit: DNV

• DNV says berths, storage, and transfer windows could become the next constraint on LNG bunker supply
• Newbuilding orders now concentrated in the 18,000 to 20,000 cbm range, with Asia commissioning some of the largest units
• Converting small-scale LNG carriers offers a faster route than newbuilds, but "is not a simple notation exercise"
• Ammonia-specific requirements added to DNV's Gas Bunker Vessel Rules in July 2026

Adding LNG bunker vessels will not be enough on its own to keep supply in step with the LNG-fuelled fleet, with port capacity likely to become the next constraint, classification society DNV says in a new white paper on gas bunker vessels.

Last week Ship & Bunker reported the paper's headline finding that up to 208 LNG bunker vessels may be needed by 2030, but the report also argues the fleet number is only part of the picture.

"Without these complementary investments, there is a risk that constraints simply shift from vessel availability to shoreside infrastructure and port operations," the paper says, listing storage capacity, dedicated berths, compatible transfer systems, and digital scheduling tools as the areas where ports need to invest.

Pressure is already building around port readiness, berth availability, and transfer windows, it adds.

"In this context, LNG bunkering competes not only with other fuels, but also with time, space, and operational margin."

The paper also says recent disruption to LNG flows through the Strait of Hormuz has exposed how quickly regional availability can change, putting extra pressure on bunkering capacity in markets already seeing strong demand growth.

Bigger Ships

On the fleet itself, DNV says newbuilding activity is increasingly concentrated in the 18,000 to 20,000 cbm range, aimed at major international hubs and hub-and-spoke supply, while smaller barges continue to serve port-based trades.

Europe remains the most established region, centred on ARA, Zeebrugge, Marseille, and Gibraltar, but Asia is described as the main growth engine, with Singapore the leading hub and China rapidly expanding ship-to-ship capability across several major ports.

To add capacity faster than newbuilds allow, the paper points to converting existing small-scale LNG carriers, which already have cryogenic containment, boil-off gas control, and emergency shutdown systems.

It cautions that conversion "is not a simple notation exercise", with the main challenge being transfer compatibility across different receiving vessels' manifolds, hoses, couplings, and shutdown logic, where mismatches "may create unsafe surge pressures, uncontrolled releases, or delayed isolation".

Ammonia Rules

Looking beyond LNG, DNV says it introduced ammonia-specific requirements in the July 2026 edition of its Gas Bunker Vessel Rules, first written in 2014 for hydrocarbon gases.

The additions cover transfer connection arrangements, enhanced deck water spray, fixed water monitors for toxic vapour dispersion, leak detection at transfer connections, toxic zones, and dedicated emergency stations, along with nitrogen inerting to reduce the risk of stress corrosion cracking in ammonia cargoes.

The rules arrive as the first ammonia bunker vessel described as operational has entered service in China.

The white paper can be downloaded here.