Methanol as a Marine Fuel: A Global Perspective on Technology, Economics, and Environment

The maritime industry is exploring alternative fuels to reduce greenhouse gas and pollutant emissions from ships. Methanol has emerged as a promising marine fuel worldwide, offering a combination of cleaner combustion and practical handling characteristics. Unlike heavier conventional fuels, methanol contains no sulfur and has a high hydrogen-to-carbon ratio, leading to cleaner exhaust and potentially lower carbon dioxide (CO₂) emissions per unit of energy. Major shipping companies and engine manufacturers have begun adopting methanol fuel technology, and dozens of methanol-fueled vessels are now in operation or on order globally. This article provides a comprehensive overview of using methanol as a marine fuel – from the underlying combustion chemistry and engine technology to fuel handling requirements – and examines broader considerations such as economic viability, regulatory frameworks, and environmental impacts. Case studies of pioneering methanol-fueled ships (including vessels from Maersk and Stena Line) are presented, and methanol is compared against other emerging alternative marine fuels like liquefied natural gas (LNG), ammonia, and hydrogen to highlight its advantages and limitations.

Technical Aspects of Methanol Fuel Use

Combustion Characteristics and Engine Technology

Methanol (chemical formula CH₃OH) is an alcohol fuel that burns to produce CO₂ and water, with no sulfur oxide emissions. It has a low cetane number and high octane, meaning it is resistant to auto-ignition in a diesel engine. In practice, marine diesel engines must be adapted to ignite methanol reliably. The most common solution is a dual-fuel compression ignition approach: a small amount of pilot fuel (typically marine diesel oil) is injected to initiate combustion of methanol in the cylinder. Engine makers like MAN Energy Solutions and Wärtsilä have developed dual-fuel engines specifically for methanol. For example, MAN’s ME-LGI series and Wärtsilä’s methanol retrofit kits allow large two-stroke and four-stroke engines to operate on methanol by using high-pressure direct injection and pilot ignition. These engines retain performance similar to conventional diesel engines while running on methanol. In fact, the first methanol-fueled ship, the ferry Stena Germanica, was converted in 2015 by retrofitting its four Wärtsilä medium-speed engines for dual-fuel operation. Since then, the technology has matured significantly – Methanex’s subsidiary Waterfront Shipping has a fleet of methanol-fueled tankers with MAN two-stroke engines that have accumulated over 500,000 operating hours on methanol, demonstrating reliability and performance in real service. Today, methanol-capable engines are available in a wide range of power ratings, and multiple newbuild ships are being equipped with these engines, indicating a high level of technical readiness.

From a combustion standpoint, methanol’s adiabatic flame temperature is lower than that of diesel fuel, which can result in lower peak engine temperatures and reduced formation of nitrogen oxides (NOₓ) during combustion. Experiments have shown that methanol combustion can achieve up to about 40–50% reduction in NOₓ emissions compared to conventional diesel, thanks to its cleaner-burning properties (no carbon-to-carbon bonds in the fuel molecule to produce soot, and lower combustion temperatures). However, meeting the strict IMO Tier III NOₓ standards may still require additional measures. Engine developers have found that strategies like water emulsification or direct water injection into methanol can further suppress NOₓ formation, potentially allowing compliance with Tier III limits without exhaust aftertreatment. Overall, methanol combustion emits negligible particulate matter (soot) and no sulfur oxides, given the fuel contains no sulfur. Carbon dioxide emissions from the engine exhaust are roughly proportional to fuel consumption; methanol has slightly lower carbon content per unit of energy than heavy fuel oil, contributing to a modest reduction in CO₂ emissions on a tank-to-wake basis. If methanol is produced from renewable feedstocks, the overall carbon footprint can be dramatically lower (see the Environmental Impact section below).

In addition to use in internal combustion engines, methanol can also serve as a hydrogen carrier for fuel cells. Projects have demonstrated on-board reforming of methanol to hydrogen to power proton-exchange membrane fuel cells – for example, the MS Innogy, a small passenger ferry in Germany, uses a direct methanol fuel cell system. While fuel cell applications are still experimental in shipping, they highlight methanol’s versatility as both an engine fuel and an energy source for emerging propulsion technologies.

Fuel Storage and Handling Onboard

One of methanol’s key advantages is that it is a liquid at ambient temperature and pressure, simplifying storage compared to cryogenic fuels. Methanol can be stored in ordinary mild steel tanks, similar to those used for diesel, although careful material selection is needed because methanol is a polar solvent that can be corrosive to certain metals and can degrade some common fuel-system polymers. Tank coatings or stainless steel materials are often used in storage and fuel systems to ensure compatibility. Importantly, methanol’s energy density is lower than that of diesel: by weight it contains about 19.7 MJ/kg (versus roughly 42 MJ/kg for diesel), and by volume it requires about 2.5 times the volume to store the same energy content as conventional fuel. This means ships need larger fuel tanks (or more frequent bunkering) to achieve the same range. In practical terms, naval architects must allocate additional space for methanol fuel – for instance, Stena Germanica’s retrofit involved converting some ballast tanks into methanol fuel tanks to provide sufficient fuel capacity. On newbuild methanol vessels, designers have managed this issue by optimizing tank layout; notably, Maersk’s latest methanol-fueled container ships have been designed to complete long ocean voyages (e.g. an Asia-Europe roundtrip) on a single bunkering of methanol, despite its lower energy density, by making use of available hull volume for fuel storage.

Methanol is classified as a low-flashpoint flammable liquid (flashpoint around 12°C), which brings additional safety requirements for marine use. The IMO’s IGF Code (International Code of Safety for Ships Using Gases or Other Low-Flashpoint Fuels) has developed interim guidelines (adopted in 2020) specifically for methyl/ethyl alcohol fuels. These regulations mandate measures to ensure safety equivalent to traditional fuels. Key design considerations include: locating methanol tanks away from heat sources and protected from external damage, double-walled piping for fuel lines or ventilated pipe ducts, inert gas systems for tank atmosphere control to prevent flammable vapor mixtures, and leak detection and fire suppression systems tailored to alcohol fires. Methanol burns with a nearly invisible flame, so flame detectors (UV/IR sensors) are used instead of reliance on visual cues. Ship crews require training to handle methanol safely, given its toxicity if ingested or inhaled in high concentration and the different fire suppression techniques (alcohol fires can be extinguished with water, unlike oil fires which often require foam). Fortunately, because methanol is a liquid fuel, many existing bunkering practices and equipment can be adapted from conventional fuel oil service. Typical methanol bunkering involves closed loading systems to minimize vapor release, and new safety interlocks to manage the low flashpoint. Several ports have started using dedicated methanol bunker barges and tanker trucks outfitted for alcohol fuel transfer. Overall, while additional precautions are needed, the storage and handling of methanol on ships are more straightforward than for LNG (which needs cryogenic tanks at –162°C) or hydrogen (which requires cryogenic or high-pressure systems). Ships can leverage much of the existing liquid fuel infrastructure with modifications, which lowers the barrier to methanol adoption.

Economic Considerations

The economic viability of methanol as a marine fuel depends on fuel pricing, engine/fuel system costs, and the regulatory drivers that incentivize low-carbon operations. On a pure energy-content basis, methanol today is often cost-competitive with marine diesel. For example, in 2024 the spot price of methanol in major hubs (Houston, Rotterdam, Singapore) hovered around $300–$400 per metric ton. Since one ton of methanol contains only about half the energy of a ton of diesel, roughly two tons of methanol are needed to equal the energy of one ton of diesel. In effect, at $325 per ton, the cost per unit of energy from methanol is similar to buying diesel at about $650 per ton. Marine gasoil (MGO) in 2024 has often been in that price range, meaning running a ship on methanol can be economically on par with conventional fuel from a fuel-cost perspective. Of course, these figures fluctuate with market conditions, but they indicate that methanol is not prohibitively expensive as a fuel, especially when compared to other alternative fuels (for instance, LNG prices spiked in recent years, and hydrogen or ammonia fuels are expected to be significantly more costly per energy unit until production scales up).

Using renewable methanol (such as bio-methanol produced from biomass or e-methanol produced from green hydrogen and CO₂) currently comes at a premium. Estimates suggest green methanol could be 1.5–2 times the cost of fossil methanol. However, large shipping customers and operators have shown willingness to absorb these costs for the sake of decarbonization goals. Maersk, for instance, has noted that even if they paid double for green methanol, the impact on consumer goods transport cost is minimal – on the order of a few cents increase for a pair of shoes shipped intercontinentally. Moreover, environmental regulations are poised to change the economics in favor of cleaner fuels. The FuelEU Maritime initiative in the EU and the extension of the EU Emissions Trading Scheme (ETS) to shipping will effectively put a price on carbon emissions. Over time, the cost of emitting CO₂ (or the cost of using high-carbon fossil fuels) will rise steeply. Industry analysis suggests that by 2050 the added compliance cost of burning fossil fuel could exceed $2000 per ton of fuel, via carbon taxes or credit costs – a massive economic penalty that carbon-neutral fuels would avoid. This regulatory pressure creates a strong incentive to invest in methanol capability early. In addition, mechanisms like carbon intensity pooling (where a fleet’s overall emissions can be averaged) reward the use of ultra-low carbon ships: one recent study showed that a single e-methanol fueled ship could offset the emissions of dozens of heavy-fuel-oil ships in such a pooling scheme, far outpacing what an LNG-fueled ship could offset. These policy factors improve the business case for methanol despite an upfront cost to retrofit or build new vessels.

On the capital expenditure side, converting a ship to run on methanol or ordering a newbuild with a dual-fuel methanol engine entails some cost increase. However, these costs are generally lower than for LNG fuel adoption. Methanol conversion mainly requires adding fuel handling systems (pumps, double-wall piping, tank modifications) and engine retrofits like new injectors and control systems. Companies like Wärtsilä have performed such conversions (e.g. on Stena Line ferries) and indicated that the scope, while significant, is manageable within a normal dry-docking period. In contrast, converting to LNG would require installing cryogenic tanks and vapor handling systems, a much more complex and expensive endeavor. This relative affordability is one reason the ship orderbook for methanol-capable vessels has surged. By late 2023, over 100 large ships capable of burning methanol were on order globally – including container ships, tankers, car carriers, and bulk carriers – a number that had grown to rival or exceed the orders for LNG-fueled tonnage. This trend suggests that shipowners see methanol as a reasonably cost-effective path for fleet decarbonization. Another economic consideration is fuel availability: methanol is already a globally traded commodity (around 90 million tons per year of production). The existing production is mostly used for chemical industries, but it means supply chains and storage infrastructure are well established across the world. As of 2024, around 120 seaports already have some methanol storage capacity, and dedicated bunkering facilities for ships are being developed at major hubs. Furthermore, many new projects are underway to produce green methanol in large volumes. Industry projections show over 20 million tons per year of renewable methanol production could be online by 2030, backed by investments in Europe, North America, the Middle East, China, and elsewhere. These developments give some confidence that if ships adopt methanol, the fuel will be available and increasingly sustainable, supporting the economics in the long term.

Regulatory and Policy Framework

Regulation plays a pivotal role in enabling and encouraging the use of methanol on ships. Safety regulations for using methanol fuel have been formulated under the IMO’s IGF Code. In 2015, work began to draft guidelines for low-flashpoint alcohol fuels, and by late 2020 the IMO approved interim guidelines for methyl/ethyl alcohol fuels and fuel cells. These guidelines specify the safety requirements mentioned earlier (double-walled piping, ventilation, gas detection, etc.) to ensure that methanol-fueled ships operate as safely as those using LNG or other fuels. Classification societies such as DNV, ABS, Lloyd’s Register, and others have also published rules and notations for methanol as a marine fuel, meaning ship designs can be approved and classed for methanol service. As of 2025, many flag states and ports accept methanol-fueled vessels under these frameworks – for example, flag administrations in Europe and Asia have been closely involved in pilot projects and are generally supportive as long as IMO guidelines are followed. One challenge on the regulatory side has been the need for crew training and emergency response preparedness, which the IGF Code addresses through requirements for training crew on handling low-flashpoint fuels.

Environmental regulations are a major driver behind methanol adoption. The IMO’s MARPOL regulations cap sulfur content in fuels (the “IMO 2020” global sulfur cap of 0.5% m/m, and 0.1% in Emission Control Areas), which methanol easily meets since it contains no sulfur at all. This means methanol-fueled ships inherently comply with sulfur emission limits without needing scrubbers or very low sulfur fuels. For NOₓ emissions, new engines must meet IMO Tier III standards in designated emission control areas. Some methanol engines can meet Tier III with the aforementioned water injection techniques; others may require add-on aftertreatment (like selective catalytic reduction) if operating extensively in NOₓ emission control zones. Still, the reduction in NOₓ from methanol combustion (even without aftertreatment) is a beneficial aspect that helps operators move toward compliance.

The larger push comes from greenhouse gas (GHG) reduction targets. The IMO has set an ambition to cut international shipping’s GHG emissions by at least 50% by 2050 (from 2008 levels) and is evaluating even more stringent targets (up to full decarbonization by 2050 in some proposals). To reach these goals, the IMO has introduced mechanisms like the Carbon Intensity Indicator (CII) and Energy Efficiency Existing Ship Index (EEXI) to encourage ships to use cleaner fuels and technologies. A ship running on methanol (especially green methanol) can significantly improve its CII rating due to lower CO₂ emissions per ton-mile, helping it avoid penalties or restrictions as the CII requirements tighten over time. Regionally, the European Union has taken bold steps: as noted, the EU is including maritime emissions in its cap-and-trade carbon market and enforcing the FuelEU Maritime rules that mandate a gradual reduction of a ship’s GHG intensity starting in 2025. These policies effectively push ship owners to adopt fuels like methanol, which can be net-zero on a lifecycle basis if sourced renewably. In some cases, governments and ports also offer incentives – such as reduced port fees for low-emission vessels or funding support for pilot projects. For instance, the conversion of Stena Germanica to methanol was part-funded by the EU’s Motorways of the Sea initiative, underscoring policy support for early adopters. In summary, the regulatory environment is increasingly aligned with the transition to alternative fuels: it provides the safety rules needed for methanol’s use and imposes environmental costs on traditional fuels, thereby enhancing methanol’s attractiveness.

Environmental Impact

Using methanol as a fuel can bring significant environmental benefits in terms of emissions reduction. At the exhaust (tank-to-wake), a ship burning methanol produces zero sulfur oxides (SOₓ) and negligible particulate matter (PM). This is a stark improvement over heavy fuel oil, which historically has caused high SOₓ emissions (a main contributor to acid rain and harmful particulates) and visible soot. Even compared to distillate fuels like marine gasoil, methanol’s lack of aromatic compounds and sulfur leads to much cleaner exhaust with virtually no soot. The absence of soot and lower peak combustion temperatures also means less black carbon, an important climate pollutant that results from incomplete combustion of heavy hydrocarbons. For nitrogen oxides (NOₓ), as discussed, methanol tends to produce lower NOₓ than conventional fuels – studies and field trials have indicated roughly 30–50% reductions in NOₓ emissions when running on methanol compared to marine diesel oil, although the exact reduction depends on engine tuning and use of any NOₓ control technologies. If further NOₓ mitigation is needed, methanol exhaust can be treated with catalytic converters (SCR systems) effectively since the exhaust is free of sulfur (sulfur can poison catalysts in SCR systems, so methanol’s clean exhaust is easier to treat).

Regarding greenhouse gases, the direct CO₂ emissions from burning methanol are slightly lower per unit of power generated than for burning diesel. This is because methanol’s chemical carbon content relative to its energy content is lower – it carries hydrogen which contributes energy without carbon. However, because more methanol fuel must be consumed to get the same power (due to its lower energy density), the net CO₂ emitted for a given voyage using fossil methanol can be comparable to a ship on diesel. The real GHG benefit of methanol comes when it is produced from renewable or low-carbon pathways. Methanol can be made from a variety of feedstocks: natural gas (the most common current method), coal (in China, for example), biomass (by gasifying agricultural or forestry waste), municipal solid waste, or even directly from CO₂ and hydrogen (power-to-methanol). If methanol is produced from natural gas without carbon capture, the lifecycle CO₂ savings versus oil fuel are modest. But bio-methanol produced from biogenic sources (like manure, landfill gas, or biomass) can have a dramatically lower lifecycle carbon intensity – often 60–95% lower GHG emissions well-to-wake, since the carbon in bio-methanol was recently absorbed from the atmosphere by plants. Some bio-methanol pathways can even be net-negative in carbon emissions (for instance, when methane that would have been released from manure is instead captured and converted to methanol, preventing that methane from escaping). Similarly, e-methanol produced with renewable electricity and carbon dioxide (captured from the air or industrial sources) can be nearly carbon-neutral. In early 2023, one of Waterfront Shipping’s tankers (MV Cajun Sun) completed a transatlantic voyage using a blend of bio-methanol that achieved net-zero lifecycle GHG emissions – an important real-world demonstration of methanol’s potential to eliminate carbon emissions when sustainable feedstocks are used. As the production of bio and e-methanol scales up, more such voyages and even continuous operation on net-zero fuel could become feasible, enabling shipping companies to reach their decarbonization pledges.

Another environmental merit of methanol is its behavior in case of a spill. Methanol is water-soluble and biodegradable; if released into the marine environment, it will rapidly dilute and biodegrade within days. It does not persist or create long-term contamination of water or coasts as heavy oils do. While methanol in high concentration is toxic to marine life (and humans), the fact that it disperses and breaks down relatively quickly means the environmental damage from an accidental spill would be much less severe than an oil spill of similar volume. This property makes methanol attractive from a pollution mitigation perspective – it inherently carries less risk of ecological disaster. Additionally, methanol’s toxicity is primarily an ingestion and inhalation hazard (it is poisonous to humans if ingested), but it is not carcinogenic and does not bioaccumulate in food chains. Ships using methanol will still need stringent procedures to avoid and contain spills or leaks, but the worst-case scenario is more benign than with heavy oil or even diesel spills.

It’s worth noting that methanol does not emit methane, a potent greenhouse gas, during combustion – an advantage it holds over LNG. LNG-fueled engines can suffer from methane slip (unburned methane passing through the engine), which undermines their GHG benefits since methane has a much higher global warming potential than CO₂. Methanol is a single-carbon molecule and any unburned fuel would be methanol vapor (which, while a volatile organic compound, is not a long-lived GHG like methane). Thus, from a climate perspective, methanol avoids the methane slip issue entirely. There are some environmental considerations specific to methanol: for example, low levels of formaldehyde can be present in methanol exhaust due to partial oxidation of the fuel. Formaldehyde is a toxic pollutant, but modern engine tuning and aftertreatment can keep such emissions very low, and regulators are aware of managing this aspect. Overall, compared to traditional marine fuels, methanol offers a much cleaner emissions profile across the board. When considering full lifecycle impacts, the use of renewable methanol can virtually eliminate net carbon emissions, making it one of the leading candidates to achieve truly sustainable shipping.

Case Studies of Methanol-Fueled Vessels

Stena Germanica (Ro-Pax Ferry)

A notable early adopter of methanol fuel was the Stena Germanica, a 240-meter roll-on/roll-off passenger ferry operating in Northern Europe. In 2015, Stena Line converted this ferry’s propulsion system from diesel to methanol dual-fuel – making it the world’s first commercial vessel running on methanol. The conversion, done in collaboration with Wärtsilä and naval architects at Stena, involved retrofitting four Wärtsilä 8-cylinder medium-speed engines (each about 4 MW output) to run on methanol with diesel pilot ignition. Additional equipment installed included a high-pressure methanol fuel pump room (to supply methanol to the engines at about 600 bar injection pressure), double-walled fuel piping throughout the ship, and new tank instrumentation and safety systems according to developing guidelines. Some of Stena Germanica’s ballast tanks were repurposed to carry methanol fuel, providing a total capacity of around 300 cubic meters of methanol. After the conversion, the ferry successfully re-entered service on its route between Gothenburg (Sweden) and Kiel (Germany). In operation, Stena Germanica showed that methanol could achieve dramatic cuts in emissions: sulfur and particulate emissions effectively eliminated, and NOₓ reduced on the order of 40–60% relative to its previous diesel operation, all while maintaining performance. The crew and operator also gained valuable experience in handling methanol bunkering and fuel management. This project was a “ground-breaking innovation,” according to Stena Line, and it proved the concept for others. As of 2023, Stena has continued investing in methanol – it has ordered new hybrid ferries that will run on methanol, and is working to convert additional existing vessels. The Stena Germanica case demonstrated to the industry that retrofitting for methanol is feasible and that the fuel can be safely used on a large passenger ship in regular service.

Waterfront Shipping and Methanol Tankers

Waterfront Shipping (WFS), a subsidiary of Methanex Corporation (the world’s largest methanol producer), has been a pioneer in operating methanol-fueled ocean tankers. Starting in 2016, WFS introduced a series of 49,000 DWT chemical tankers equipped with MAN B&W ME-LGI two-stroke engines capable of running on methanol or fuel oil. One of the first of these was the Taranaki Sun, soon followed by sister ships like Manchac Sun and Cajun Sun. These vessels trade globally carrying methanol (as cargo) and uniquely use their own product as fuel. Over the years, WFS expanded this fleet; by 2020, they had around a dozen methanol dual-fuel tankers in operation. As mentioned, cumulatively this fleet has logged hundreds of thousands of hours on methanol fuel, providing a rich dataset on engine performance, fuel efficiency, and maintenance in real-world conditions. The operational experience has been overwhelmingly positive – MAN reported that these methanol engines showed efficiency on par with conventional engines and even slightly improved efficiency in some cases. The dual-fuel concept (methanol with a small diesel pilot) proved robust across different loading conditions and voyages. Importantly, the WFS tankers demonstrated methanol’s practical advantages, such as simpler fuel handling compared to LNG and the ability to bunker methanol at various ports without major infrastructure overhauls (often using tank trucks or existing chemical terminals). WFS also partnered in trials of using bio-methanol blends. In 2023, one of their vessels, Cajun Sun, completed the world’s first net-zero emission voyage using a blend of bio-methanol that had a negative carbon footprint – effectively achieving zero lifecycle emissions for that trip. This milestone was achieved by blending biomethanol (from renewable sources) with conventional methanol, yielding an overall carbon-neutral fuel mix. For the shipping industry, WFS’s fleet serves as proof that methanol is not just a theoretical alternative fuel but a practical one powering routine voyages worldwide.

Another set of methanol tankers has come from a joint venture between Stena Bulk (the tanker arm of Stena) and Proman Shipping (part of Proman, a methanol producer). Proman Stena Bulk ordered several newbuild IMO II methanol tankers (around 50,000 DWT, known as the IMOIIMAX MR design) from Guangzhou Shipyard in China. The first ships, like Stena Pro Patria and Stena Pro Marine, were delivered in 2022–2023 and immediately went into service running on methanol fuel. These ships have state-of-the-art energy-efficient hull designs and MAN dual-fuel methanol engines. Each consumes roughly 12,000–13,000 tons of methanol fuel per year. Proman Stena Bulk’s strategy is to use methanol produced by Proman’s own plants (in Trinidad and elsewhere) as a cleaner fuel for their shipping activities, aligning business with environmental goals. As of 2024, the JV has at least four such vessels delivered and a couple more on the way, and they have made headlines by bunkering methanol in ports like Rotterdam and New Orleans. These case studies in the tanker sector underscore that methanol fuel is viable for long-haul deep-sea shipping, not just short-run ferries. They also show the synergy when fuel producers invest in downstream usage, helping to kick-start the market for new fuels.

Maersk Container Ships

Perhaps the most significant endorsement of methanol as a marine fuel has come from A.P. Moller–Maersk, one of the world’s largest container shipping companies. In 2021, Maersk announced the order of the world’s first methanol-fueled container ship – a small feeder vessel of around 2,100 TEU capacity – intended to operate in the Baltic by 2023 using green methanol. This move was quickly followed by much larger orders: Maersk committed to a series of large ocean-going container ships capable of running on methanol. By the end of 2022, Maersk had ordered a fleet of twelve 16,000 TEU methanol dual-fuel container ships from South Korean shipbuilder Hyundai Heavy Industries, slated for delivery starting 2024. Not stopping there, in 2023 Maersk placed additional orders, including a recent batch of six mid-sized (9,000 TEU) dual-fuel ships from Yangzijiang Shipbuilding in China, for delivery in 2026–2027. In total, Maersk has over 20 methanol-capable newbuilds on order, making up a substantial portion of their newbuilding program. These ships will use MAN B&W two-stroke engines (ME-LGIM type) designed for methanol, and Maersk’s intention is to operate them on carbon-neutral e-methanol or bio-methanol as it becomes available.

Maersk’s bold investments have catalyzed the development of a global methanol bunker supply network. The company has been actively signing supply agreements for green methanol – for example, with producers in Europe (Denmark and Norway), North America (the USA), and Asia (China), aiming to secure enough fuel to run the first vessels as they hit the water. The first of Maersk’s large methanol-fueled container ships was launched in mid-2023 and embarked on its maiden voyage in 2024, marking a new era for big ship propulsion. These vessels, operating on major routes (such as Asia-Europe or transpacific trades), send a strong signal that methanol is scalable to the largest classes of ships. Maersk’s leadership has stated that from 2023 onward, any new vessel they order will be capable of using carbon-neutral fuel – and currently, their preferred choice is methanol. This choice rests on methanol’s relative readiness: the engines exist now, and green methanol production is ramping up, whereas other alternatives like ammonia or hydrogen are not yet deployable at scale. Maersk’s competitors have taken note; several other container lines have since made plans for methanol-fueled ships (for instance, CMA CGM and COSCO have each announced orders for large newbuilds that can use methanol). The push by such global carriers indicates that methanol could become a mainstream alternative fuel for the container sector within this decade.

Other Notable Projects

Beyond the major commercial operators, there are numerous pilot and research projects using methanol fuel. The Alfred Wegener Institute in Germany, for example, has built a research vessel (RV Uthörn) launched in 2022–2023 that runs on methanol, being one of the first methanol-powered research ships. Cruise line AIDA (part of Carnival Corporation) initiated a project to test a methanol fuel cell on the cruise ship AIDAnova in 2021, aiming to integrate a 1 MW fuel cell as a auxiliary power source and explore the practicalities of using methanol as a clean energy carrier in the cruise sector. These projects illustrate interest in methanol across different marine segments, including passenger transport and scientific research. Each successful pilot adds confidence in methanol’s applicability and helps refine guidelines and best practices.

Comparison with Other Alternative Marine Fuels

The landscape of alternative marine fuels includes several contenders – each with distinct properties, benefits, and challenges. Below is a comparative overview of methanol versus three prominent alternatives: LNG, ammonia, and hydrogen.

Methanol vs. Liquefied Natural Gas (LNG)

Maturity and Availability: LNG has been used as a marine fuel for over a decade, with a growing fleet of LNG-powered ships and established bunkering infrastructure at major ports. Methanol is newer in shipping use but is catching up quickly; dozens of methanol-fueled ships are in service or on order, and methanol is available at many ports as a widely traded chemical. Unlike methanol, LNG requires cryogenic storage and specialized bunkering (pipes, compressors, etc.), making infrastructure setup more involved.
Energy Density: LNG (primarily methane) has a high energy content per mass, but its low liquid density at –162°C means it still needs about 1.8 times the volume of diesel for the same energy. Methanol needs about 2.5 times the volume of diesel for equal energy. While LNG holds a slight volumetric efficiency edge, its tanks must be spherical or cylindrical and heavily insulated, which eat up space. Methanol’s ambient-temperature tanks can be shaped to the ship’s hull (including use of void spaces), giving designers more flexibility to mitigate lost cargo volume.
Emissions: Both LNG and methanol eliminate SOₓ and greatly reduce PM emissions. LNG can reduce CO₂ emissions by roughly 20% compared to oil fuel (due to methane’s lower carbon content), but this is highly sensitive to methane slip – any unburned methane leaked through the engine directly contributes to greenhouse warming (methane’s GWP is about 28 times CO₂ over 100 years). Unfortunately, some LNG ship engines (e.g. older low-pressure dual-fuel designs) have slip rates that erode or even negate the CO₂ benefit. Methanol engines do not have this issue; their GHG performance depends on the feedstock of the methanol. If running on fossil methanol from natural gas, the CO₂ emissions are similar to an LNG ship when considering the full fuel production and use cycle, but if running on renewable methanol, the GHG emissions are far lower. In terms of NOₓ, high-pressure LNG engines (like ME-GI) can meet Tier III without aftertreatment, whereas methanol might need water injection or SCR to fully meet Tier III in all cases – however, both fuels can comply with the aid of technical solutions.
Safety: LNG is cryogenic and stored at about –162°C; a leak can form a flammable gas cloud and risk of cryogenic burns. Methanol, being a liquid, poses a flammability risk (with low flashpoint) but no extreme low-temperature hazards. LNG vapors are methane, which is lighter than air and will dissipate upward; methanol vapors are heavier than air and linger, but methanol’s lower volatility at ambient temperature means leaks tend to form liquid pools that evaporate more slowly compared to LNG’s instant gas expansion. Both fuels require robust safety systems. One advantage of methanol is that existing crews might find handling a liquid fuel more familiar than handling cryogenic LNG.
Engine Technology: The marine engine industry has developed reliable dual-fuel engines for both LNG and methanol. LNG engines come in two flavors – low-pressure Otto cycle (with methane slip) and high-pressure Diesel cycle. Methanol engines use high-pressure Diesel cycle with pilot fuel. Both achieve similar efficiencies to pure diesel engines. Converting existing diesel engines to LNG is complex (due to needing cryo pumps, new cylinder heads, etc.), whereas converting to methanol is relatively simpler (mostly adding new injection system and compatible fuel supply components).
Infrastructure and Logistics: Bunkering LNG often requires specialized bunker barges or terminals; boil-off management is a constant factor (LNG gradually warms and boils off, which must be used or reliquefied). Methanol has the logistic advantage of being liquid at ambient conditions, allowing use of standard tanker trucks or fuel barges with minor mods. It also does not evaporate away like LNG – it can be stored long-term in a tank with minimal losses. From a logistics standpoint, integrating methanol into global fuel supply may be easier since it can piggyback on the existing petrochemical distribution network.
Bottom Line: LNG is a proven transitional fuel with significant air quality benefits and moderate carbon benefits, but it is still fossil-derived and comes with methane slip concerns and complex handling. Methanol offers similar air quality benefits, a potentially much lower carbon footprint if produced renewably, and easier handling, but requires larger fuel storage volume on board. Many view methanol as a more future-proof choice given its compatibility with net-zero carbon goals and simpler retrofit potential.

Methanol vs. Ammonia

Carbon Emissions: The most touted advantage of ammonia (NH₃) as a fuel is that it contains no carbon; burning ammonia yields no CO₂. This makes it an attractive long-term zero-carbon fuel (assuming it is made from green hydrogen and renewable power). Methanol does contain carbon, so it will emit CO₂ when burned unless that carbon is offset by how the fuel is made. However, methanol can be produced in carbon-neutral ways (using atmospheric CO₂), essentially making it a net-zero carbon fuel as well. So the difference lies in combustion emissions: ammonia can be carbon-free at point of use, whereas methanol always emits some CO₂ when used (but overall can be neutral if sustainably sourced).
Energy Density and Storage: Ammonia has an even lower energy density than methanol in volumetric terms. Liquid ammonia at ambient pressure must be stored at –33°C or pressurized to about 10 bar at room temperature. Its volumetric energy density is about 12.7 MJ/L, substantially lower than methanol’s ~16 MJ/L. Ships using ammonia will need large, insulated tanks (though not as cold as LNG’s). The storage challenge for ammonia is comparable to LNG in requiring special tank materials (ammonia is corrosive to many metals like copper and zinc, and it can embrittle steel) and designs (to handle pressure or refrigeration). Methanol’s storage is simpler and more space-efficient than ammonia’s when considering the total fuel system (tank plus insulation, etc.).
Combustion and Engine Readiness: Ammonia is much harder to ignite than methanol; it has a very high ignition temperature and a narrow flammable range. This makes burning ammonia in engines challenging – typically a fuel like diesel or hydrogen may be needed to ignite ammonia in a dual-fuel engine. Engine developers (MAN, Wärtsilä) are currently testing prototype ammonia-fueled engines, but as of 2025 none are in commercial service yet. The first ammonia engine tests are expected around 2024–2025, with possibly initial pilot ships by the mid-2020s. In contrast, methanol engines are already commercially available and proven in service. So technology readiness is a big differentiator: methanol has at least a five-year head start over ammonia in terms of engine development and safety guidelines.
Emissions and Pollution: While ammonia combustion yields no CO₂, it is not emissions-free. Burning ammonia can produce significant NOₓ (because ammonia contains nitrogen and can form nitrogen oxides at high temperatures). Also, unburned ammonia (ammonia slip) is a toxic pollutant – even a few ppm of ammonia in exhaust can be harmful to human health, and ammonia itself is a potent greenhouse gas if released (though it has a short atmospheric lifetime). Another concern is that ammonia combustion might produce nitrous oxide (N₂O), a GHG about 265 times more potent than CO₂, if the combustion isn’t carefully controlled. These issues mean ammonia engines will likely require aftertreatment systems (like selective catalytic reduction, ironically perhaps using ammonia itself as the reagent) to clean NOₓ and limit ammonia slip. Methanol’s emissions are easier to manage – mainly NOₓ which can be reduced with water or catalyst, and no concern of a toxic slip comparable to ammonia.
Safety: Ammonia is a toxic and caustic substance. Even small leaks can create dangerous conditions for crew and responders – breathing ammonia vapor can cause severe respiratory damage. It has a pungent odor and can be detected at low concentrations (which is good as a warning), but its toxicity poses a serious safety challenge. In port or during bunkering, an ammonia spill or gas release could necessitate large evacuation zones. Methanol is flammable and toxic if ingested, but its immediate hazard is mainly fire risk rather than widespread toxic vapor. Comparatively, many consider ammonia’s safety risks to be higher and more complex to mitigate than methanol’s. Extensive safety systems (double containment, water spray curtains, respiratory protection for crew, etc.) will be required for ammonia-fueled vessels. Regulations for ammonia as a fuel are still under development in IMO, whereas methanol’s interim guidelines are already in place.
Infrastructure: Ammonia is produced in large quantities globally (mostly for fertilizer) and is shipped worldwide, so there is an existing commodity market and some port storage. However, bunker-ready infrastructure for ammonia is essentially nonexistent today – ports would need to build dedicated ammonia bunkering setups. The crossover from the fertilizer industry provides a starting point (some terminals handle ammonia), but the transition to routine fueling of vessels will require new protocols and infrastructure investments. In contrast, as noted, methanol can leverage easier routes for bunkering (tanks, trucks) and is somewhat simpler to integrate in the near term.
Use Cases: Ammonia’s main appeal is for achieving zero carbon emissions at the ship stack without relying on carbon capture or offsets. It could become a fuel of choice for long-term decarbonization if the safety and engine challenges are solved. Some large shipping companies are investing in R&D for ammonia-powered ships, expecting that by the 2030s it might be viable. Methanol, on the other hand, is sometimes seen as a “bridge fuel” – available now and scalable, helping to cut emissions immediately while the ultimate solutions (like ammonia or hydrogen fuel cells) are perfected. However, if renewable methanol becomes plentiful, methanol itself can be a long-term solution.
Bottom Line: Ammonia offers zero carbon combustion and high energy export potential (from regions with cheap renewable power to fuel global shipping), but it faces significant technical and safety hurdles before widespread use. Methanol is available now with established technology and fewer hazards, though it carries carbon unless produced renewably. It’s possible that methanol could be used in the interim decades, and ammonia might take a role further in the future once proven safe and reliable. Some in the industry foresee a transition where methanol paves the way (with immediate emissions reductions and building green supply chains), and ammonia might complement or succeed it in certain segments later on.

Methanol vs. Hydrogen

Physical Properties: Hydrogen has the highest energy content per mass of any fuel (120 MJ/kg), but it has an extremely low density as a gas (and even as a liquid at –253°C, its density is only 70 kg/m³). This leads to a very low volumetric energy density: liquid hydrogen provides only about 8 MJ per liter (less than half of methanol’s, and about a quarter of diesel’s). Compressed gaseous hydrogen is even less dense. For ship applications, storing enough hydrogen for long voyages is a tremendous challenge – it would require massive tanks that occupy a great deal of space, even if stored as a cryogenic liquid. Methanol, by contrast, is much denser in energy per volume (roughly double that of liquid hydrogen) and does not require cryogenics for storage. Moreover, one concept is that methanol can serve as a carrier for hydrogen: 1 ton of methanol contains about 137 kg of hydrogen (bound in its chemical structure). Instead of carrying hydrogen gas, ships might carry methanol and then either burn it or reform it into hydrogen on demand for fuel cells. This concept allows use of the existing liquid fuel infrastructure to deliver hydrogen energy in a more compact form. In essence, methanol is a hydrogen-rich liquid that is far easier to store than pure hydrogen.
Engine/Fuel Cell Technology: Hydrogen can be used in internal combustion engines (burned like a gas fuel) or in fuel cells to generate electricity. A few demonstration projects have run compression-ignition engines on hydrogen (with pilot fuel similar to methanol engines) or spark-ignition engines on hydrogen. However, hydrogen’s low ignition energy and wide flammability range make it tricky to manage in engines without backfiring or pre-ignition. The real promise for hydrogen in marine is in fuel cells, which can convert hydrogen to electricity with high efficiency and zero emissions except water vapor. Proton-exchange membrane (PEM) fuel cells are already used in certain applications (like submarines, research vessels) at small scale. Scaling fuel cells to power a large ship is a work in progress, mainly limited by cost and hydrogen storage issues. Methanol is not typically used in engines by itself (except maybe in high-compression spark engines or racing engines), but in ships it’s used in dual-fuel diesel engines with pilot fuel, as discussed. For fuel cells, there are direct methanol fuel cells (DMFCs) but they are low power; a more viable approach is using a reformer to convert methanol to hydrogen for a standard fuel cell – this adds complexity but is being explored. In summary, hydrogen fuel cell systems can achieve higher efficiency and absolutely zero emissions on board, but methanol engines are far more commercially mature and simpler in the near term.
Emissions: Hydrogen combustion (or fuel cell use) produces no CO₂, no SOₓ, no CO, and no hydrocarbons. If burned in an engine with air, it will produce some NOₓ (due to high flame temperature in air), but in a fuel cell there is no combustion so no NOₓ at all. This makes hydrogen very attractive from an emissions standpoint – truly zero-carbon and clean at point of use. Methanol, when used, will produce CO₂ (unless one captures it, which is another idea: an onboard carbon capture system could, in theory, grab the CO₂ from a methanol engine’s exhaust and later convert it back to methanol, creating a closed loop). Without carbon capture, methanol is not zero-emission at the stack, whereas hydrogen can be. However, producing hydrogen in a green way (electrolysis using renewable power) is energy-intensive and currently expensive. A lot of hydrogen today is “gray” (from natural gas with CO₂ byproduct) or “blue” (from gas with CO₂ capture) – these have some carbon footprint. Green hydrogen from surplus renewable energy is the goal, but it will require huge renewable energy deployments to support global shipping fuel demands. Methanol, in contrast, can be made from various feedstocks and might be more readily scalable in the near term (including bio-methanol options).
Safety: Hydrogen is colorless and odorless, much like LNG methane, but even lighter – it disperses upward rapidly when released. It has a wide flammability range (about 4–75% in air) and very low ignition energy, meaning even a small static spark can ignite a hydrogen leak. Handling hydrogen on ships necessitates extreme precautions to prevent leaks and ignition sources. Liquid hydrogen also poses cryogenic risks similar to LNG but even colder. Methanol’s safety issues (toxicity, flammability) are serious but more familiar and arguably easier to contain (liquid spills rather than invisible gas leaks). If hydrogen is stored as a compressed gas, the storage cylinders are high pressure (350–700 bar), which carry explosion risks if ruptured. For liquid hydrogen, the insulation and leak prevention are challenging. Essentially, hydrogen’s properties demand a very high level of engineering and detection to use safely on a large scale. Methanol’s safety management, while non-trivial, aligns more with known practices for handling flammable liquids.
Infrastructure: At present, hydrogen refueling infrastructure for ships is almost nonexistent aside from a few research projects. Supplying a large ship with hydrogen would require either on-site production or a distribution of liquid hydrogen via tanker (which currently is done only at relatively small scales for industrial use). In contrast, methanol’s infrastructure advantage has been emphasized – it can be moved in tankers, stored in tanks, and bunkered with relative ease using modified oil terminals. There are also synergies in that a future hydrogen economy could use carriers like methanol or ammonia to move hydrogen long distances; so investing in methanol now could complement a hydrogen future.
Use Cases: Hydrogen fuel might find use first in shorter-range, niche applications (harbor ferries, tugboats, etc.) where the required fuel quantity is smaller and storage is manageable, or in auxiliary power units on larger ships. Methanol is already being used for long-range ocean voyages in large ships. Some visionaries propose that ships could eventually carry liquid hydrogen in insulated tanks (much like LNG but even bulkier) for completely emission-free travel – this might happen in specific trades where governments strongly support it (for example, some plans for hydrogen-fueled ropax ferries in Norway). But for global deep-sea shipping, hydrogen in its raw form seems a distant prospect due to the storage penalty.
Bottom Line: Hydrogen offers the ultimate clean fuel promise if produced renewably – essentially no harmful emissions from the ship at all. However, the practical barriers of storage and infrastructure are huge. Methanol, conversely, is a pragmatic alternative available now and leverages existing systems at some cost to fuel density. It might serve as a mid-term solution and even as a vector to get to a hydrogen-based system (by acting as a hydrogen carrier). In sum, hydrogen is an important part of the long-term discussion, but methanol is far more ready to deploy in the immediate future for significant emissions reductions.

Conclusion

Methanol has rapidly gained momentum as a marine fuel due to its balance of favorable properties and practical implementability. Technically, it offers cleaner combustion with major reductions in air pollutants and has a well-understood liquid fuel handling profile, which eases its adoption on ships compared to gaseous or cryogenic fuels. The successful operation of methanol-powered ships – from ferries like Stena Germanica to tankers and soon large container vessels – has proven that the technology is viable and scalable. Economically, methanol is emerging as a cost-competitive option, especially as the world trends toward pricing carbon emissions and as production of renewable methanol accelerates. The existing global production and distribution network for methanol is a strong asset, positioning it as a fuel that can be sourced in many ports worldwide. Environmentally, methanol can deliver immediate benefits in terms of cleaner air around ports and coastal communities, and it holds the key to significant greenhouse gas reductions if synthesized from sustainable sources. No solution is without challenges: methanol’s lower energy density means ships must adjust designs and operations, and the fuel’s toxicity and flammability require stringent safety measures. Nevertheless, these challenges are being managed through engineering and regulatory action, as evidenced by the IMO’s dedicated guidelines and the investments by industry leaders.

In the broader context of maritime decarbonization, no single fuel will likely dominate all sectors. LNG, methanol, ammonia, hydrogen, biofuels, and even electrification will each play roles depending on vessel types, routes, and evolving technology. Methanol stands out as a compelling bridge fuel that is available now to begin cutting emissions, with the potential to remain a permanent pillar of the future fuel mix if produced sustainably. Its use does not preclude a transition to other fuels; in fact, by adopting methanol, shipowners also keep options open – the same ship infrastructure could one day use ammonia or other alcohols with modifications, or use methanol as a hydrogen carrier for fuel cells. The investments by major shipping companies (Maersk, Stena, MSC, and others) into methanol propulsion, and by energy companies into green methanol supply, suggest that a “methanol economy” in shipping is materializing on a global scale. In conclusion, methanol offers a viable pathway for the maritime sector to begin decarbonizing immediately while the ultimate mix of zero-carbon solutions matures. With its combination of technical feasibility, relatively low conversion hurdle, and compatibility with renewable production, methanol is poised to become a mainstream alternative fuel that helps steer the shipping industry toward its ambitious environmental goals.

References

American Bureau of Shipping (2021). Methanol as Marine Fuel. Sustainability Whitepaper. (Technical overview of methanol fuel properties, engine technology, and safety considerations) (Methanol as Marine Fuel) .
Holt, S. M. (2024). “Green Fuel: Methanol’s Promise.” The Maritime Executive, Aug 25, 2024. (Industry perspective on the rise of methanol fuel, with insights on market adoption, regulatory drivers, and comments from the Methanol Institute) (Green Fuel: Methanol's Promise ) .
Blenkey, N. (2023). “Maersk and Stena Line Press Ahead on Methanol Fueling.” Marine Log, June 2023. (News on recent methanol-fueled ship orders by Maersk and conversion projects by Stena Line, highlighting industry commitment to methanol) (Maersk and Stena Line press ahead on methanol fueling - Marine Log)
Methanex Corporation (2023). “Methanex and MOL Complete First-Ever Net-Zero Voyage Fueled by Bio-Methanol.” Company News Release, Mar 2023. (Details of a demonstration voyage achieving net-zero GHG emissions using a bio-methanol blend on a tanker).
Methanol Institute (2023). Marine Methanol Report – Methanol as a Future-Proof Shipping Fuel. (Comprehensive report with case studies on Maersk, Waterfront Shipping, Stena, and others; covers policy, technology, and supply developments for methanol in marine use) (Copy of Membership, Structure, Accomplishments & Goals) (Green Fuel: Methanol's Promise ).
Ammonia Energy Association Conference (2023). Presentation by L. Navin, Methanol Institute. (Data on methanol vessel orderbook, technology readiness timelines, and comparative analysis of alternative fuels, as of late 2023) (Green Fuel: Methanol's Promise ) (PowerPoint Presentation).