Explore the latest state-of-the-art academic review on alternative marine fuels. Dive into technological developments, real-world case studies, and future challenges in this comprehensive guide to cleaner shipping.
Why this topic matters in modern maritime operations
Imagine watching a large cargo ship cut through waves, but instead of plumes of smoke, it leaves a cleaner wake. Today, shipping contributes around 3 % of global greenhouse gas emissions—a tangible call for change. As academic research accelerates, shipping professionals, students, and enthusiasts need cutting-edge insight into alternative fuels that could truly transform the industry.
This review gathers the latest academic findings—especially from the past 3–5 years—on alternative marine fuels, blending evidence, real-world examples, and strategic clarity.
In-Depth Analysis
Overview of alternative fuels: trends and assessments from academia
Recent studies reviewed five key alternative fuels—LNG, methanol, ammonia, biofuels, and hydrogen—as the most promising candidates for maritime decarbonization.
Comparative reviews emphasize that achieving the Paris Agreement’s goals requires a drastic 75–85 % reduction in GHG emissions per ton-mile by 2050. Fuel choice must consider full lifecycle (well-to-wake) impacts rather than tank-to-wake emissions alone.
A series of life cycle assessment (LCA) studies in the last five years examined LNG, hydrogen, methanol, ammonia, and biofuels—analyzing them in terms of production, storage, transport, ship use, environmental impact, and cost.
Well-to-Wake emissions: comparing green vs fossil pathways
One of the most important developments in academic literature is the focus on well-to-wake emissions. Green methanol and green ammonia consistently demonstrate superior performance compared to fossil-based LNG or grey methanol.
When only tank-to-wake results are measured, ammonia shows strong results, but when full lifecycle impacts are analyzed, renewable methanol achieves the most balanced profile. This underlines the need for fuels produced from renewable sources rather than fossil-derived ones.
Emerging trends: bibliometric insights and green synthetic fuels
Research mapping over decades shows a growing focus on alternative marine fuels, with notable contributions from research communities in Europe, Asia, and North America.
Electrofuels—synthetic fuels made from CO₂ plus green hydrogen—are gaining attention as drop-in replacements that could drastically lower lifecycle emissions.
Another review integrates alternative fuels with fuel cells and ship energy systems, offering a holistic view of shipboard green propulsion technologies.
Safety, regulation, and policy landscape
The legal and regulatory framework is struggling to keep pace. Current maritime conventions inadequately address safety and environmental risks for ships using fuels like hydrogen or ammonia—raising concerns about spills, vapor dispersion, and bunkering safety.
At the policy level, the IMO’s Net-Zero Framework, drafted in 2025 and expected to take effect from 2028, introduces a global carbon pricing mechanism of around 100 US dollars per tonne of CO₂. Earlier targets include a 40 % reduction in emissions intensity by 2030 and full net-zero by 2050.
Real-World Applications and Case Illustrations
Green methanol scaling up
By 2023, around 100 methanol-burning ships had been ordered by major shipping companies, mostly featuring dual-fuel engines. The container ship Laura Maersk, the first to run on green methanol, entered service in 2023, followed by Ane Maersk.
Green hydrogen and ammonia adoption
At COP28, shipping leaders called for an end to fossil-only vessels. Green methanol and ammonia are now recognized as scalable alternatives. Shipbuilders and operators are investing in multi-fuel designs capable of switching as fuel availability evolves.
Hydrogen fuel-cell vessels
Norled’s MF Hydra, the world’s first liquid hydrogen-powered ferry, began sailing in Norway in 2023—signaling real-world hydrogen adoption.
Cruise shipping developments
Cruise lines like Hurtigruten aim for climate-emission-free electric ships by 2030. LNG has been promoted as a transitional fuel, but methane leakage risks and limited port infrastructure raise concerns. The cruise sector is under pressure to demonstrate credible low-emission pathways.
FAQ
Why does it matter to differentiate green vs fossil-based alternative fuels?
Lifecycle emissions differ vastly. Only fuels produced from renewable pathways consistently meet strict emissions targets.
Which alternative marine fuels are most promising academically?
Research points to green methanol and green ammonia as top performers, with LNG and hydrogen serving as transitional options.
How is regulation evolving?
The IMO’s Net-Zero Framework will introduce global carbon pricing from 2028. Earlier targets aim for 40 % cuts in emissions intensity by 2030, and full net-zero by 2050.
What about safety and legal frameworks?
Current maritime law inadequately tackles risks related to alternative fuels. Policymakers must adapt frameworks for bunkering safety, liability, and pollution control.
Are there real vessels using these fuels?
Yes—green methanol ships by Maersk, hydrogen ferries like MF Hydra, and multi-fuel dual-capability designs are already sailing.
What’s the research trend?
Studies increasingly focus on lifecycle assessments, synthetic electrofuels, technology integration (e.g., fuel cells), and bibliometric mapping of global research.
Future Outlook
As the maritime sector sets sail toward decarbonization, academic and policy developments show a clear direction:
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Green methanol and ammonia will likely take center stage, with hydrogen and electrofuels emerging as scalable solutions.
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Full lifecycle assessments must guide investment and regulatory decisions.
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Safety standards and legal frameworks need rapid adaptation to address new fuel risks.
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Flexible ship design, enabling dual or multi-fuel capacity, will future-proof the global fleet.
The transition is not a single leap but a phased journey. With coordinated action, shipping can become not just cleaner, but also more resilient and forward-looking.
References
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Zhang, W. (2025). Review of the state-of-the-art of alternative marine fuels. ScienceDirect.
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Wang, Y., & Wright, L. A. (2021). A Comparative Review of Alternative Fuels for the Maritime Sector. World, 2(4), 456–481.
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Wang, Y. (2025). A Review of LCA Studies on Marine Alternative Fuels. Journal of Marine Science and Engineering.
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Zamboni, G. (2024). Well-to-Wake analysis of LNG, methanol, ammonia. PMC.
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Moshiul, A. M. (2022). Bibliometric review on alternative marine fuels. Sustainability.
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Review of alternative fuels, ship systems & fuel cells. (2025). Frontiers in Marine Science.
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Wang, Q. (2023). Legal analysis of risks with alt-fuel ships. Frontiers in Marine Science.
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IMO Net-Zero Framework (2025 draft). Wikipedia.
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IMO GHG Strategy & targets. Wikipedia.
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Methanol fuel adoption & Maersk’s green methanol ships. Wikipedia.
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Green fuels & shipping commitment at COP28. Time Magazine.
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Hydrogen ship—MF Hydra. Wikipedia.
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Cruise industry and alternative fuels challenges. The Guardian.
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Shipping decarbonization targets and policy trends. Reuters.