15.04.2026
Fuel used to be one of the simplest decisions in shipping. Ships ran on heavy fuel oil or marine gas oil for roughly 60-70 years, particularly from the 1960s, when motor ships overtook steamships. At that time, most operational planning focused on efficiency, routing and maintenance rather than the fuel itself.
That long period of stability is beginning to change as the sector responds to tighter environmental rules and growing pressure to reduce emissions. International shipping accounts for around 2–3% of global greenhouse gas emissions, which has placed the industry under increasing scrutiny from regulators, investors and cargo owners alike.
In response, the International Maritime Organisation (IMO) has set a course for international shipping to reach net-zero greenhouse gas emissions around 2050, with interim targets aimed at gradually lowering carbon intensity across the sector. As these targets begin to influence vessel design, fuel supply and operational planning, alternative marine fuels such as methanol, ammonia, hydrogen, LNG and biofuels are gaining attention as substitutes for traditional bunker fuel.
If you work in maritime operations, the real value lies in understanding which of these fuels could realistically work for the vessels you operate, the routes you sail and the infrastructure available in the ports you rely on.
Alternative marine fuels are fuels used in place of traditional bunker fuels to reduce emissions and support sustainable shipping. In maritime shipping, these fuels replace heavy fuel oil or marine diesel, which have powered most commercial vessels for decades.
The term generally refers to fuels being explored as the industry seeks lower-emission options to make shipping safer and smarter. They are increasingly central to maritime decarbonisation strategies and the industry’s transition to green shipping.
Some of the fuels currently receiving the most attention include:
Many of these fuels are part of global marine engineering trends. They are being studied because they can reduce greenhouse gas emissions or other pollutants compared with conventional bunker fuel, depending on how they are produced and used.
Several forces are pushing shipping companies to rethink the fuels they use. Environmental regulation is one part of the picture, but it is not the only one. Shipowners today are balancing compliance requirements, commercial pressure from customers and long-term investment decisions about their fleets.
A few developments are driving the growing interest in alternative marine fuels:
Together, these pressures are encouraging the industry to explore new fuel options and rethink how ships are powered across different types of maritime operations to tackle global shipping challenges.
When you begin evaluating alternative marine fuels, the conversation quickly moves beyond simple emissions comparisons. Ship operators have to think about how a fuel fits into the day-to-day reality of running a vessel.
Identifying the most suitable alternative marine fuel requires balancing environmental performance, operational practicality and long-term regulatory compliance.
A fuel may look promising on paper, but if it creates operational complications or supply challenges, it becomes far harder to adopt at scale. Operators usually assess several practical factors before considering a new fuel viable.
One of the first things to consider is how much energy the fuel can store. Traditional marine fuels such as heavy fuel oil contain a high amount of energy relative to the space they occupy.
Some alternative fuels have lower energy density, which means ships may need larger or additional fuel tanks to achieve the same range. This can affect vessel design and, in some cases, reduce cargo space.
Alternative fuels also introduce different storage conditions and handling procedures. For example:
These technical requirements influence vessel design, onboard systems and crew training.
A fuel also needs to be available where ships operate. Even if a fuel performs well technically, it becomes difficult to adopt if it cannot be reliably bunkered across global ports.
Infrastructure for LNG has expanded significantly in recent years, while supply chains for fuels such as ammonia and hydrogen are still developing. Limited availability can make large-scale adoption difficult, particularly for vessels operating on long international routes.
Every fuel introduces its own safety and regulatory framework. Operators need to understand how fuels behave in storage, transfer and combustion.
This includes factors such as toxicity, flammability and ventilation requirements, which influence both vessel design and onboard operating procedures.
Finally, shipowners look at how regulations and classification rules are evolving. Guidance from regulators and classification societies helps determine whether a fuel can be used safely and legally in commercial operations.
Because these frameworks are still developing for several fuels, many operators continue to evaluate multiple fuel options rather than committing to a single pathway.
Even after a fuel passes technical evaluation, operators still need to consider how it fits into the real operating profile of a vessel. Fuel decisions often depend less on theory and more on developing green growth skills that will help you understand where ships sail, what they carry and which ports they visit. A few operational factors often shape those decisions.
Newbuild vessels can be designed around specific fuel systems from the start, while retrofitting existing ships often requires technical compromises.
Alternative fuels are becoming an important part of how the maritime sector approaches green shipping. As the industry works to reduce emissions, fuel choices will increasingly influence vessel design, propulsion systems, port infrastructure and global fuel supply chains. What is becoming clear is that shipping is unlikely to rely on a single replacement for conventional bunker fuel. Instead, the transition will likely involve multiple fuels used across different parts of the industry, depending on operational needs.
For maritime professionals, this transition is also changing the skills needed across operations, engineering and fleet management. Understanding how different fuels behave, how they are stored and how they fit within evolving regulations is becoming increasingly important.
As shipping companies explore new fuels and technologies, the industry is also seeing growing demand for professionals who understand the operational, environmental and regulatory aspects of maritime sustainability. This has made education a central part of maritime decarbonisation.
At MLA College, our MSc Sustainable Maritime Operations programme is designed to help you develop this expertise. This kind of specialised knowledge can help you bridge the gap between technical innovation and practical decision-making at sea.
The transition to alternative marine fuels will not happen overnight. But as environmental expectations continue to evolve, understanding how different fuels work in real maritime operations will become increasingly important for professionals across the sector.
Contact us to learn more about our MSc Sustainable Maritime Operations programme and how it can help you build expertise in sustainable shipping and maritime decarbonisation.
Alternative marine fuels are energy sources used instead of traditional heavy fuel oil or marine diesel. Examples include LNG, methanol, ammonia, hydrogen and biofuels, which are being explored as options to reduce emissions in maritime shipping and support green shipping initiatives.
Shipping is under increasing pressure to reduce greenhouse gas emissions and meet international environmental targets. Alternative fuels are being studied because they can potentially lower emissions and help the industry move towards more sustainable maritime operations and long-term maritime decarbonisation.
Ship operators usually consider factors such as energy density, storage requirements, fuel availability, safety considerations and regulatory guidance when evaluating alternative marine fuels.
Yes. LNG is already used on some commercial vessels, while methanol-fuelled ships are beginning to enter service. Other fuels, such as ammonia and hydrogen, are still being developed and tested for wider use.
Current industry research suggests that shipping will likely use a mix of fuels rather than a single universal solution, with different fuels suited to different vessel types and trading routes.
