Introduction: Decarbonizing the Blue Economy
The shipping industry is the lifeblood of global trade, but it is also one of the hardest sectors to decarbonize. International shipping accounts for roughly 3% of global greenhouse gas emissions. To meet the International Maritime Organization (IMO) target of reaching net-zero emissions by or around 2050, the industry is looking toward hydrogen as a cornerstone of its “green” fleet.
While batteries are suitable for short ferry routes, the high energy demands of ocean-going cargo ships require a fuel with higher energy density—making hydrogen and its derivatives the leading contenders for the future of the high seas.
1. Fuel Cells vs. Internal Combustion
There are two primary ways ships can use hydrogen to generate power:
- Hydrogen Fuel Cells: These are becoming commercially proven for smaller vessels and harbor craft. In 2025, megawatt-scale pilots are de-risking this technology for larger ships, offering silent, zero-emission propulsion where the only byproduct is water.
- Hydrogen Internal Combustion (H2 ICE): Engines can be modified to burn hydrogen directly or as a blend. Dual-fuel engines already exist that can run on a mix of 15% to 25% hydrogen alongside traditional fuels, providing a bridge for existing fleets.
2. The Form Factor: Liquid Hydrogen & LOHCs
Hydrogen’s biggest challenge in shipping is its volume. To store enough energy for a long voyage, hydrogen must be significantly condensed:
- Liquid Hydrogen (LH2): Cooling hydrogen to -253°C shrinks its volume significantly. Projects like the Energy Observer 2—a cargo ship powered by liquid hydrogen—are aiming for 100% operational capacity on commercial routes by 2030.
- Liquid Organic Hydrogen Carriers (LOHC): These “carrier liquids” allow hydrogen to be stored and transported at ambient temperatures using existing oil terminal infrastructure, potentially saving billions in new construction costs.
3. The “Derivatives”: Ammonia and Methanol
Because pure hydrogen is difficult to store, the maritime industry is heavily invested in “hydrogen carriers”:
- Green Ammonia: Contains no carbon and is easier to liquefy than pure hydrogen. It is currently considered one of the most promising fuels for long-distance, deep-sea shipping.
- Green Methanol: While it contains carbon, it is a net-zero fuel if produced using biogenic carbon. It is already being adopted by major shipping lines due to its relative ease of handling.
4. Regulatory Wind at the Back
Global policies are now forcing the transition:
- IMO 2030 Targets: The IMO has set a goal for zero or near-zero emission fuels to represent at least 5% to 10% of shipping energy by 2030.
- FuelEU Maritime: This regulation mandates a gradual reduction in the greenhouse gas intensity of energy used onboard ships, effectively making green hydrogen derivatives a requirement for vessels calling at European ports.
Conclusion
The maritime industry is entering a “commercial boom” for hydrogen technology. From hydrogen-powered ferries in Norway to the world’s first hydrogen bulk carriers scheduled for 2027, the “Blue Economy” is rapidly turning green.
Next Up: We’ve looked at the ships; now let’s look at the skies. In Article 14, we ask: Can planes fly on green hydrogen?