Significant strides are currently being made on ammonia and hydrogen as marine fuels. Read on to learn more about when these new fuels are likely to arrive, and how to best prepare for them.
The IMO set a target in 2023 to cut at least 40% of greenhouse gases in international shipping by 2030, with 5–10% of all energy sources being replaced by new, zero emission alternatives.
However, what is good for the environment at large, introduces new hazards for the environment on board.
Where current fuels are mainly associated with hydrocarbon fire risk, ammonia and hydrogen are linked to high-toxicity and explosion risk, respectively.
Read on to learn more about when these new fuels are likely to arrive, and how to best prepare for them.
Ammonia moves into early deployment as marine fuel
2025 saw the first completely renewable ammonia supply chains being established in China. Ammonia driven engines are now reaching 100% load, and some are slated to go operational in Norway as early as 2027.
IMO has already issued interim guidelines for the safety of ships using ammonia as fuel. Training is still exceedingly rare, with the first cohort of seafarers being trained in ammonia as marine fuel in India, December 2025.
It seems likely that a limited amount of regulated early deployments will be the rule towards 2030, with more meaningful adoption on a fleet scale throughout the following decade.
Hydrogen currently in use for short-sea deployment
While still not in common use, there are examples of short-sea deployment of hydrogen fueled vessels. One instance is the MV Sea Change in San Francisco, a public ferry in use since July 2024.
IMO has not yet released concrete training guidelines for hydrogen fuel specifically. However, their guidelines for alternate fuels include those for fuel cells, which is the currently most common implementation of hydrogen.
Further interim guidelines for hydrogen (and ammonia) have been finalized at sub-committee level, but not yet gone through the final approval steps.
We may see more common adoption of hydrogen fuel from the mid 2030s, assuming storage volume penalties and bunkering complexity can be sufficiently solved.
What risks are associated with ammonia and hydrogen?
Both of these new fuel sources place greater demands on gas detection. Periodic checks will no longer be enough.
Ammonia is a toxic hazard, requiring constant, fixed detection in fuel preparation rooms, tank connections, ventilation exhausts, and other defined hazardous zones. In addition to its dangerous effect on humans, it acts corrosively with certain materials such as copper.
Hydrogen is highly flammable, and difficult to contain. The tiny molecules make it more susceptible to leakage. It will require very fast detection, ventilation integrity and tightly established shutdown procedures.
Hydrogen vs ammonia vs existing fuel (oil fuel: MGO/HFO)
To sum up, gas detection at sea is only going to grow in importance for the next 10–20 years, as a consequence of new fuel types.
Below is a table outlining how they are different from existing oil fuel, as well as the recommended procedures to handle them:
| Category |
Existing fuel (MGO/HFO) |
Ammonia (NH₃) |
Hydrogen (H₂) |
Maturity in deep-sea shipping
|
Standard and widespread
|
Early stage; interim IMO guidance exists
|
Limited; mainly short-sea pilots and demonstrations
|
Primary onboard hazard driver
|
Fire/explosion + toxic combustion products in incidents
|
High toxicity (exposure control dominates) |
High flammability and rapid dispersion; ventilation dependency
|
Detection focus
|
Hydrocarbon gas/LEL in machinery spaces where applicable; CO/CO₂ in specific contexts
|
Toxic gas detection in defined zones + integration with shutdown/ventilation
|
Fast leak detection + tight integration with ventilation/shutdown
|
Likely detection architecture
|
Mix of fixed in selected areas + portable routines
|
Expanded fixed detection coverage; portable as verification
|
Expanded fixed detection coverage; high integrity “detect–alarm–shutdown” chain
|
Logistics burden for detection readiness
|
Manageable, but still dependent on calibration and spares
|
Higher (toxic-gas sensors, calibration gas, spares, and traceability)
|
Higher (specialized sensors, verification routines, commissioning)
|
| Category |
Mature SOLAS/ISM baseline
|
Interim IMO ammonia safety guidelines (MSC.1/Circ.1687)
|
Interim guidance progressing via IMO sub-committee work; formalization ongoing
|
| Category |
Established STCW/ISM norms
|
Additional training expected under generic interim alternative-fuels training guidance
|
Same training direction; higher focus on leak response and ventilation failures
|
Hydrogen vs ammonia vs existing fuel
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