In the past we explored the Facts and Myths around the upcoming alternate fuel sources on cruise ships, primarily LNG and Fuel Cells. Instead of updating that post, I think a new deep-dive into it is warranted as we’ve seen unprecedented advancements and adaptation of that technology.
BACKGROUND
The maritime industry has made significant strides toward cleaner energy since 2020. While small ferries, riverboats, and offshore supply vessels pioneered the transition to LNG, cruise lines have emerged as leaders among major shipping companies in adopting greener technologies. Today in 2025, dozens of major cruise ships operate using LNG, with fuel cell technology gaining momentum as a supplementary power source.
This shift represents a crucial step away from heavily polluting bunker fuels (marine grade diesel oil and fuel oil). LNG combustion eliminates sulfur emissions and reduces carbon dioxide output by approximately 25% compared to traditional fuels—a significant improvement for vessels that consume enormous amounts of energy.
ENVIRONMENTAL REGULATIONS
The EPA’s designation of Environmentally Controlled Areas (ECAs) around all U.S. coastal waters continues to shape industry practices. Ships entering these zones must use low-sulfur fuel oil, which comes at a premium cost due to additional refining requirements and limited global supply.
Many cruise lines have installed exhaust gas cleaning systems (“scrubbers”) on their vessels, allowing them to continue using less expensive fuels while achieving emissions comparable to low-sulfur alternatives. However, this represents only an intermediate solution as the industry moves toward truly clean energy sources.
LNG IMPLEMENTATION ON MODERN CRUISE SHIPS
Liquefied Natural Gas begins as methane, which is extracted through methods including hydraulic fracturing. The gas is then super-cooled and pressurized into liquid form for efficient transportation. By 2025, the LNG infrastructure has expanded significantly, with major energy companies like Shell, QatarGas, and Engie continuing to lead the market.
Safety Considerations
Despite common misconceptions, properly stored LNG presents minimal safety risks. LNG only combusts under specific conditions—when 5-15% methane mixes with oxygen and encounters an ignition source of sufficient temperature. If released, LNG rapidly evaporates before reaching combustible concentrations in a process called ‘boil off’. Modern cruise ships incorporate sophisticated safety systems that exceed regulatory requirements.
Storage Requirements
Carnival Corporation’s Excel-class, Royal Caribbean’s Icon-class, and MSC’s World-class all now operate multiple LNG-powered vessels, with storage tanks carefully integrated into ship designs to minimize impact on passenger spaces.
The bunkering infrastructure has expanded significantly since 2020, with major cruise ports in Europe, North America, and Asia now offering LNG refueling capabilities. This has resolved one of the primary obstacles that initially slowed adoption.
FUEL CELL TECHNOLOGY
Fuel cells generate electricity through chemical reactions between fuel (typically hydrogen) and oxygen across ceramic plates. When pure hydrogen serves as the fuel source, the only emission is water vapor—a truly zero-emission solution.
The basic reaction is:
2H₂ + O₂ → 2H₂O + electricity
When methane substitutes for hydrogen, the emissions include water and some oxides, still significantly cleaner than conventional propulsion systems.
Fuel Cells in Maritime Applications
Since 2023, Royal Caribbean’s Icon of the Seas has demonstrated the practical application of fuel cell technology, using it to power hotel functions including lighting, entertainment systems, and various onboard amenities. This hybrid approach—combining LNG for propulsion with fuel cells for hotel loads—has proven effective at reducing overall emissions.
The partnership between Royal Caribbean and Meyer Werft, along with thyssenkrupp Marine Systems, has yielded significant advancements in maritime fuel cell applications. Current systems primarily use LNG as the fuel medium rather than pure hydrogen, balancing practicality with environmental benefits.
Viking Ocean Crusies and Fincantieri announced in early 2025 that the Viking Libra, currently under construction in Italy at Fincantieri’s Ancona yard, will be the world’s first cruise ship powered by a hydrogen-based hybrid propulsion system when she debuts in late 2026. The system, developed with support from Fincantieri’s subsidiary Isotta Fraschini Motori, integrates liquefied hydrogen storage with advanced fuel cells capable of generating up to six megawatts of electrical power, enabling zero-emission operations.
THE CURRENT STATE AND FUTURE OUTLOOK
As of 2025, LNG has established itself as a viable transition fuel for the cruise industry, with multiple major cruise lines operating LNG-powered vessels. Fuel cell technology has progressed from experimental to practical application, though primarily as a supplementary rather than primary power source.
The next frontier appears to be green hydrogen production—creating hydrogen fuel through renewable energy rather than from fossil sources. Several cruise lines have announced pilot projects to test hydrogen fuel cells powered by green hydrogen, potentially offering a truly zero-emission solution for future vessels.
The maritime industry’s journey toward sustainability continues to evolve, with cruise lines remaining at the forefront of innovation. While challenges remain, the progress made since 2020 demonstrates the industry’s commitment to reducing its environmental footprint while maintaining the exceptional experiences that passengers expect.