Headline Initiative
Mining giant BHP, energy company Engie, and other partners have committed to a two-year pilot that tests onboard ammonia cracking systems aboard vessels to generate hydrogen in situ for propulsion or auxiliary power.
This approach aims to enable vessels to carry ammonia (as an energy carrier) and convert it onboard into hydrogen, reducing reliance on conventional fossil marine fuels or external hydrogen fueling.
Project Design & Technical Approach
Ammonia Cracker Technology
The pilot will deploy cracking reactors that decompose ammonia (NH₃) into hydrogen and nitrogen. This hydrogen can then be used in fuel cells or hydrogen-powered systems to drive propulsion or auxiliary loads.
One technology provider involved is Pherousa, whose ammonia-to-hydrogen cracker system is slated for installation on electric ultramax vessels in the trial.
A key design requirement is high purity hydrogen: trace ammonia impurities must be minimized, especially when hydrogen is used in proton exchange membrane (PEM) fuel cells that are sensitive to contaminants.
Partnerships & Vessel Application
The trial includes BHP, Engie, Berge Bulk, and ammonia supply firms. The vessels involved are electric ultramax bulk carriers that will carry the cracking units alongside ammonia tanks.
Approval in Principle (AiP) from classification societies like ABS has already been granted for Pherousa’s technology, providing early regulatory and technical validation.
Why This Matters in Maritime Decarbonization
- Ammonia as a Hydrogen Carrier
Ammonia is attractive as a marine fuel or hydrogen vector because it is easier to store than pure hydrogen (higher volumetric density, existing supply chains).
By cracking ammonia on board, ships can carry ammonia fuel and convert it only when needed, avoiding the challenges of hydrogen storage or infrastructure at ports. - Emission Reduction & Operational Flexibility
This strategy could reduce carbon emissions if the ammonia is produced via green processes (from renewable hydrogen). It also provides vessels flexibility to switch to hydrogen usage without requiring complete overhaul of storage systems.
Moreover, such onboard systems could help in meeting stringent IMO or regional greenhouse gas emission targets for shipping, by offering a pathway toward lower-carbon propulsion.
Challenges & Technical Considerations
- Efficiency losses: Cracking ammonia and then using hydrogen in fuel cells incur energy losses. Some studies suggest round-trip efficiencies (from ammonia → hydrogen → electricity) may be modest.
- Purity & contamination: Ensuring negligible ammonia traces in the hydrogen stream is critical to avoid damaging fuel cells or reducing performance.
- Scale & durability: The system must be robust, compact, and reliable in the marine environment, operating over long voyages, variable loads, and harsh conditions.
- Ammonia supply chain & carbon origin: The environmental benefit depends heavily on whether the ammonia is produced from renewable hydrogen (green ammonia) versus fossil fuel–derived ammonia (grey or blue).
- Regulatory & safety concerns: Storing ammonia onboard poses handling, toxicity, and safety issues, which must be addressed via certification, sensor systems, and containment.
Recent Analogues & Precedents
- In Spain, a supply vessel named Bertha B was fitted with an onboard ammonia cracker and membrane reactor by H2SITE, converting ammonia into high-purity hydrogen to power auxiliary systems via a PEM fuel cell.
- That system reportedly operated with an integrated membrane reactor that avoids separate gas separation steps, helping maintain purity and efficiency.
- H2SITE asserts that its cracker subsystem achieves ~90% conversion efficiency, and coupled with a fuel cell yields a usable output, though overall system efficiency and well-to-wake emissions remain under scrutiny.
Outlook & Strategic Implications
- If the pilot succeeds, onboard ammonia cracking could become a key technology pathway for shipping’s transition away from fossil marine fuels.
- It lowers reliance on hydrogen bunkering infrastructure by leveraging ammonia as a transportable hydrogen vector.
- Large resource owners and industrial energy players (like BHP, Engie) participating sends a market signal: shipping decarbonization is not just a niche domain but of cross-sector strategic importance.
- However, the economics, operational robustness, emissions benefits, and regulatory acceptance must all align for widespread adoption.
In sum, this project marks a bold step toward reimagining how hydrogen can be carried, processed, and used in maritime settings. While challenges remain, the trial will provide essential real-world data on performance, safety, and trade-offs—insights that could help shape the future of green shipping.