GCMD modelling exposes the gap between dual-fuel capacity and actual low-carbon fuel use

A new modelling study from the Global Centre for Maritime Decarbonisation (GCMD) and Boston Consulting Group puts a sharper operational distinction into the shipping fuel transition: installing dual-fuel capability and actually consuming a low-carbon fuel are not the same decision.

Published on 16 September, the study models fleet, fuel-cost and policy pathways to 2050. In its base case, with the IMO Net-Zero Framework’s Tier-2 penalty held at USD 380 per tonne of CO2e, methanol dual-fuel engines represent about 10% of fleet engine capacity in 2050, while methanol supplies only about 2% of fleet energy consumption. GCMD’s explanation is economic: vessels can retain the option to use methanol but continue to burn cheaper fuels when fuel-price and regulatory conditions favour them.

The study’s stronger-price scenario is deliberately illustrative, not a forecast. If the global penalty rose to USD 700/tCO2e by 2050, new fuels, including drop-in fuels, reach about 61% of fleet energy use in the model. GCMD also finds no clear all-in cost winner between e-methanol and e-ammonia through 2050. Ammonia’s production-cost advantage is substantially offset by logistics and handling requirements, including specialised training, larger exclusion zones and more complex bunkering.

For ports, the report identifies two potential ammonia-hub models: production-linked hubs with access to lower-cost supply, and import-aggregation hubs that combine marine demand with nearby industrial and power demand. By contrast, liquid fuels such as methanol and ethanol may reinforce established bunkering hubs because they are comparatively easier to transport and deliver.

**Why this matters:** Owners and charterers should treat fuel-ready tonnage, contracted fuel volumes, and verified bunkering capability as separate exposure lines. For operators and masters, the practical issues extend beyond engine availability to procedures, crew competence, terminal interfaces and contingency arrangements. Cargo interests, insurers and P&I stakeholders should expect the transition to create more variable operational profiles and documentation needs, especially where a vessel’s nominal fuel capability differs from its fuel actually consumed.

The policy setting remains unsettled. The IMO says further work on draft Net-Zero Framework measures and implementation guidance is scheduled before MEPC 85 in late November and early December 2026. The GCMD–BCG findings should therefore be read as scenario-based decision support, not as evidence that a global carbon-price level or fuel mix has been agreed.