LNG-Fueled Vessels: A Comprehensive Global Review (2025)

Executive Summary

Liquefied Natural Gas (LNG) has emerged as a leading alternative fuel in the maritime industry, offering significant reductions in air pollutants and a moderate reduction in greenhouse gas emissions compared to traditional marine fuels. This report provides a detailed analysis of three key segments of LNG-fueled vessels: ocean-going ships, LNG bunkering vessels, and LNG-fueled port support vessels (such as harbor tugs). It covers technological developments, economic considerations, environmental impacts, regulatory frameworks, and current fleet data for each category on a global scale, using the most current data available (through 2024–2025).

Key findings include:

• Rapid Growth of LNG-Fueled Fleet: The number of LNG-fueled ocean-going vessels has grown exponentially in recent years. By the end of 2024, roughly 640 LNG-powered ships were in operation worldwide (excluding LNG carriers that transport LNG as cargo). This represents a doubling of the fleet since 2021 and a 33% increase just in 2024. LNG-fueled vessels now span multiple sectors including container ships, tankers, bulk carriers, car carriers, cruise ships, ferries, and offshore support vessels.

• LNG Bunkering Infrastructure Expansion: To support the growing fleet, LNG bunkering vessels (ships that transport and transfer LNG fuel to others) and port facilities have expanded globally. Over 60 dedicated LNG bunkering vessels are in service as of 2024 (up from just a handful several years ago), operating in nearly 200 ports that offer LNG bunkering. Major bunkering hubs in Europe, Asia, and North America have invested in larger, more capable bunkering ships to fuel the new generation of LNG-powered ocean vessels.

• Port Support Vessels: A small but increasing number of harbor tugs and port service vessels are now LNG-fueled. Approximately a dozen LNG-fueled tugs are in operation globally, deployed in pioneering ports in Europe, Asia, and North America. These vessels demonstrate the feasibility of LNG in intense short-haul operations and contribute to cleaner air in port regions.

• Technological Developments: LNG-fueled ships utilize advanced dual-fuel or pure gas engines and cryogenic fuel storage systems. Ocean-going ships often employ dual-fuel two-stroke engines (capable of burning LNG or diesel) and large insulated tanks. Bunkering vessels and tugs typically use specialized LNG tank types (e.g. Type C pressure vessels) and may feature hybrid-electric systems. Continuous innovation is addressing challenges such as methane slip (unburned fuel emissions) through improved engine designs and aftertreatment technologies.

• Economic Considerations: The economics of LNG as marine fuel involve both benefits and trade-offs. LNG-fueled newbuild ships generally cost more upfront (estimated 10–20% higher capital cost due to fuel tanks and systems), but they can yield operational savings when LNG fuel prices are competitive. In 2024, LNG bunker prices have often been lower than very low sulfur fuel oil (VLSFO) in major ports, improving the fuel cost advantage for operators. Early adopters have also benefited from avoiding the costs of sulfur scrubbers and from incentives such as reduced port fees or higher charter rates for green vessels. However, fuel price volatility (as seen during the 2022 gas market spike) and the additional training and infrastructure requirements pose economic risks to be managed.

• Environmental Impact: LNG delivers a substantial reduction in harmful air pollutants. Switching from traditional heavy fuel oil to LNG virtually eliminates sulfur oxide (SOₓ) emissions and particulate matter, and can reduce nitrogen oxides (NOₓ) by up to 80–90% depending on engine technology. These improvements yield significant health and environmental benefits, especially in port cities and coastal areas. In terms of greenhouse gases, LNG fuel can lower carbon dioxide (CO₂) emissions by roughly 20% on a per voyage basis. However, methane (the primary component of LNG) is itself a potent greenhouse gas if released unburned; the industry is actively working to minimize methane slip from engines. Looking ahead, LNG-fueled ships offer a pathway to further decarbonization by transitioning to bio-LNG or synthetic methane (which are compatible with existing LNG ship technology) as those fuels become available.

• Regulatory Landscape: Regulatory drivers have been pivotal in the adoption of LNG fuel. The IMO 2020 global sulfur cap and stringent Emission Control Areas forced shipowners to seek sulfur-free fuel solutions, positioning LNG as a compliant fuel without the need for exhaust scrubbers. LNG engines can also meet IMO Tier III NOₓ standards required in emission control zones. The International Code of Safety for Gas-Fueled Ships (IGF Code), in force since 2017, provides a uniform framework for the safe design and operation of LNG-fueled vessels, and classification societies have developed rules and notations to guide these designs. On the horizon, climate regulations (IMO’s decarbonization strategy and regional measures like the EU Emissions Trading Scheme and FuelEU Maritime rules) are pressuring shipping to cut greenhouse gas emissions. LNG is viewed as an interim solution that can meet current environmental rules and potentially achieve net-zero emissions in the future when coupled with renewable LNG alternatives. Ports and governments worldwide have supported LNG bunkering infrastructure through policies and funding, as seen in the EU’s Alternative Fuels Infrastructure regulations mandating LNG availability at core ports and similar initiatives in Asia and the Americas.

Each of the following sections delves deeper into these points for the specific vessel categories. Real-world examples and leading industry players are highlighted to illustrate the state of practice. Data is drawn from reputable industry sources including classification society databases, industry coalitions, research firms, and operator reports. The report concludes with an outlook on the role of LNG in the maritime energy transition and a reference list of sources.

Introduction

LNG has gained momentum as a marine fuel over the past decade in response to stricter environmental regulations and the shipping industry’s pursuit of cleaner operations. LNG is natural gas cooled to liquid form at –162°C, reducing its volume for storage. When used as fuel, LNG must be stored in cryogenic tanks and vaporized to feed gas-burning engines. Although this requires special handling and investment, LNG offers significant emissions advantages and has matured into a viable solution for a range of vessel types.

Drivers of LNG adoption: Several converging drivers have led to the rise of LNG-fueled vessels:

• Air Emissions Regulations: The IMO’s 0.5% global sulfur cap (effective 2020) and 0.1% sulfur limits in Emission Control Areas virtually eliminated the use of high-sulfur residual fuels without treatment. LNG contains no sulfur, allowing ships to meet these rules without exhaust scrubbers. Likewise, LNG’s low nitrogen content and combustion characteristics can enable compliance with IMO Tier III NOₓ limits in designated coastal areas without requiring add-on technologies in certain engine designs. These regulatory benefits made LNG an attractive compliance strategy.

• Environmental and Social Pressure: Shipping faces increasing pressure from the public and customers to reduce its environmental footprint. LNG produces far lower particulate and smog-forming emissions, yielding immediate air quality improvements. Forward-looking companies adopted LNG to demonstrate environmental leadership, reduce health impacts near ports, and align with corporate sustainability goals. Some cargo owners now prefer or incentivize cleaner vessels in their supply chain.

• Greenhouse Gas Strategy: While LNG is still a fossil fuel, it burns more efficiently with roughly 20% less CO₂ emissions per unit of energy than oil-based fuels. Many industry stakeholders view LNG as a “bridge fuel” that can cut greenhouse gas emissions in the near term while paving the way for renewable fuels. LNG-fueled vessels can later transition to bio-LNG (biomethane) or synthetic methane (made from renewable electricity), leveraging existing investments. This future compatibility provides a level of “future-proofing” as the IMO and regional regulators tighten GHG targets towards 2030 and 2050.

• Economic Factors: Historically, natural gas has often been cheaper on an energy-equivalent basis than marine petroleum fuels, albeit with regional variability. In periods of ample supply, LNG fuel prices can offer significant savings. For example, in early 2024 LNG bunker prices in Singapore were roughly USD $100 per ton lower than conventional VLSFO fuel, after having swung from a premium during the 2022 energy crisis. These price dynamics, combined with avoidance of costs for sulfur scrubbers and the possibility of premium charter rates for cleaner ships, have created a compelling business case in many scenarios. Various ports and governments have also introduced financial incentives (such as reduced port dues or grants) for LNG-fueled ships and bunkering infrastructure.

• Mature Technology and Safety Framework: LNG propulsion technology has benefited from decades of experience on LNG carriers that routinely used boil-off gas as fuel. Over the last ten years, engine manufacturers and shipbuilders have developed reliable dual-fuel engines and integrated fuel systems for broader ship types. The IMO’s IGF Code and class society rules now provide clear guidelines to ensure safety, which has increased confidence among ship owners, operators, and insurers in adopting LNG. Extensive training programs and standards for LNG bunkering have also been established, mitigating operational risks.

Global uptake: As a result of these drivers, LNG-fueled shipping has transitioned from niche pilot projects to a mainstream option. The fleet of LNG-fueled vessels has grown at an accelerating pace. In 2010, only a handful of non-LNG carrier ships (mostly small ferries in Norway) were running on LNG. By 2015 there were around 60–70 such vessels, and by 2020 the number surpassed 175. Growth has since surged as major deep-sea shipping sectors embraced LNG.

Figure: Growth in the number of LNG-fueled ships in operation worldwide (excluding LNG cargo carriers). The uptake has accelerated in response to emissions regulations and industry decarbonization efforts, with the fleet expanding from only a few vessels in 2010 to over 600 by 2024.

According to data from classification society DNV’s Alternative Fuels Insight platform, approximately 641 LNG-fueled ships were in service by the end of 2024 – more than double the count in 2021. Moreover, the orderbook for new LNG-capable vessels remains strong. In 2024 alone, shipowners ordered over 250 additional LNG-fueled vessels (from containerships to tankers and car carriers), indicating that the global LNG-fueled fleet is on track to exceed 1,000 vessels by the late 2020s. Notably, these figures exclude the fleet of LNG carrier ships, nearly all of which also use LNG boil-off gas for their own propulsion. If LNG carriers are included, the overall count of ships capable of burning LNG would be significantly higher; however, the focus of this report is on vessels adopting LNG primarily as a fuel choice (rather than as cargo).

Segmenting the LNG-fueled fleet: This report categorizes LNG-fueled vessels into three main groups for analysis:

1. LNG-Fueled Ocean-Going Vessels: These are large commercial ships engaged in international or long-haul service, such as container ships, oil and gas tankers, bulk carriers, car/truck carriers (PCTCs), cruise ships, ferries, and offshore support vessels. These vessels have the most significant fuel consumption and emissions profiles, and many have adopted LNG to meet global and regional emissions standards.

2. LNG Bunkering Vessels: These specialized vessels are essentially floating LNG fuel trucks – they transport LNG fuel from loading terminals to LNG-fueled ships. Also known as LNG bunker vessels, they have proliferated to support the distribution of LNG to ships at major ports worldwide. They are a critical link in the LNG bunkering infrastructure, enabling ship-to-ship fuel transfer at sea or in port.

3. LNG-Fueled Port Support Vessels (Tugs and Others): This category includes harbor tugs, service vessels, and other workboats operating primarily around ports and coastal areas. These smaller vessels have begun using LNG as fuel in certain regions to curb emissions where it matters most for local air quality. Harbor tugboats, which typically have high engine power and operate near populated port areas, are a prime example.

Each of the following sections will examine one of these categories in detail, addressing the state of technology, economic considerations, environmental impact, regulatory context, and fleet status with current examples. Together, these sections provide a holistic view of the LNG pathway in maritime transportation and port operations globally.

LNG-Fueled Ocean-Going Vessels

Ocean-going ships form the largest segment of LNG-fueled vessels by tonnage and fuel consumption. This category encompasses deep-sea merchant ships and passenger vessels that have traditionally burned heavy fuel oil or marine diesel. Key sub-types adopting LNG include containerships, bulk carriers, tankers (crude, product, and LNG tankers carrying their own cargo boil-off), car carriers, and cruise ships, among others. This section explores how LNG technology is implemented on these big ships, the economics driving their use, the environmental benefits and challenges, the regulatory requirements they meet, and the current status of the fleet with real-world examples.

Technology and Vessel Design

Engine technology: Ocean-going LNG-fueled ships typically use dual-fuel engines, allowing them to run on either LNG or conventional marine fuels (like marine diesel oil) as needed. Two main types of dual-fuel engine technologies are prevalent:

• Low-pressure dual-fuel engines (Otto cycle): These inject gas at low pressure into the engine cylinders and use spark ignition or a small pilot fuel injection to ignite the air-gas mixture. This category includes medium-speed four-stroke engines used in many ferries and offshore vessels, as well as some large two-stroke engines like WinGD’s X-DF series. Low-pressure engines have the advantage of inherently low NOₓ emissions (often meeting Tier III standards without exhaust aftertreatment) and simpler fuel systems. However, they can exhibit a phenomenon called methane slip, where a portion of methane passes unburned into the exhaust. Engine designers have worked to minimize this (for example, newer X-DF engines incorporate advanced combustion control to cut methane slip significantly).

• High-pressure dual-fuel engines (Diesel cycle): These inject gas at high pressure at the end of the compression stroke, using a smaller amount of diesel fuel injection for ignition (a “pilot” fuel). MAN Energy Solutions’ ME-GI two-stroke engines are a prime example. Operating on the Diesel cycle gives these engines efficiency comparable to conventional diesel engines and virtually eliminates methane slip (since combustion is more complete). They do, however, produce higher NOₓ levels in gas mode and generally require emissions controls (like Exhaust Gas Recirculation or SCR catalysts) to meet Tier III standards. High-pressure systems are also more complex, involving pumps and compressors for the gas.

Both engine types allow fuel flexibility: ships can switch to oil-based fuel if LNG is not available or during certain maneuvers. Many LNG-fueled cargo ships carry a small amount of marine diesel for pilot fuel and backup. In practice, operators aim to use LNG for the vast majority of operations to maximize emissions and cost benefits.

Fuel storage and system: LNG must be stored in insulated, pressurized tanks to keep it cold and liquid. Ocean-going ships commonly use one or more large cylindrical Type C tanks made of cryogenic steel, typically mounted on or within the ship’s hull. Some larger vessels (especially cruise ships or very large container ships) have adopted membrane tank technology (adapted from LNG carriers) to increase fuel capacity without consuming too much space. For instance, large LNG-fueled cruise ships use membrane tanks integrated into the hull to store 3,000–4,000 cubic meters of LNG, sufficient for transoceanic range.

Key components of the fuel system include:

• Tank pressure control: LNG tanks have pressure relief systems and vapor handling to manage boil-off gas. Excess boil-off can either be reliquefied or sent to consumers (engines) to avoid venting methane to atmosphere.

• Piping and vaporizers: Vacuum-insulated pipes carry LNG from the tank to a vaporizer (heat exchanger) where it’s warmed back into gas form for the engines. All piping in occupied areas is double-walled or in ventilated enclosures per safety rules.

• Gas handling units: These regulate the flow and pressure of vaporized gas delivered to engines. They include valves, filters, and safety shut-off systems that can rapidly isolate the fuel supply in case of leaks or emergencies.

• Redundancy and safety: The IGF Code requires robust safety systems – gas and fire detection in machinery spaces, emergency shutdown systems, and double barriers between the LNG and the ship’s interior. Typically, two completely independent fuel supply lines are installed so that a leakage in one can be isolated while the other maintains operation. Vent masts direct any emergency vented gas to a safe height in the open air.

Onboard electrical and heating systems: Some LNG-fueled ships leverage the cold energy of LNG (-162°C) by using LNG evaporators that also cool air or provide refrigeration (this is a minor efficiency gain sometimes cited in design). Most other ship systems (electricity generation for onboard power, boilers, etc.) can also be configured to use boil-off gas or dual-fuel technology, further reducing reliance on oil.

Bunkering equipment: To take fuel, ocean-going ships are equipped with LNG bunkering stations – typically a set of bunkering manifolds on deck. During refueling, specialized cryogenic hoses connect the ship’s LNG intake to the supply (which could be a bunkering vessel, truck, or shore facility). Modern LNG-fueled vessels are designed with bunkering efficiency in mind; for example, manifold locations are positioned to match standard bunker vessel hose arrangements, and some ships have vapor return lines to send boil-off gas back to the bunker supplier during filling (preventing pressure build-up). Bunkering operations also involve careful protocols: inerting lines, cool-down of equipment, slow initial flow to pre-cool (to avoid thermal shock), and then high flow once conditions are stable. As LNG fueling becomes routine, vessels and bunker providers have standardized these processes to achieve turnaround times comparable to traditional fueling.

Notable developments: One technological trend is the integration of LNG fuel with other energy systems on the ship. For example, some large vessels use hybrid power setups – combining dual-fuel engines with batteries (for smoothing power demand and recovering energy). This is seen in smaller scales with LNG-fueled tugs (discussed later) and is being considered for larger ships to optimize engine load and improve efficiency. Another development is the concept of “LNG-ready” ships: vessels built with provisions to retrofit LNG fuel systems in the future. Many newbuild ships are ordered as LNG-ready (with space and structural reinforcement for future tanks), acknowledging LNG as a likely compliance fuel down the line even if they start life burning oil fuel.

Economic Considerations

Adopting LNG for an ocean-going vessel involves a range of economic factors, from construction costs to operational savings and external market conditions:

Upfront capital cost: Building an LNG-fueled ship generally incurs a premium over a conventional vessel due to the additional fuel handling systems. This includes the cost of LNG tanks (which are expensive due to materials and insulation), gas piping, vaporizers, double-walled engine components, and redundant safety systems, as well as design integration efforts. For large deep-sea ships, this capital expenditure (CapEx) premium has been estimated in the range of 10–20% relative to an equivalent oil-fueled ship. For example, a large dual-fuel containership might cost on the order of $10–15 million more than its conventional counterpart. The premium can vary by ship type and size – cruise ships with membrane tanks had higher added costs initially, whereas simpler cargo ships with standard tank types have seen the premium fall as more have been built. There are also economies of scale as yards gain experience; multiple shipbuilding programs (notably in China and South Korea) have driven down the incremental cost of LNG propulsion by standardizing designs and spreading one-time R&D costs over many vessels.

Fuel costs and savings: Operationally, the economics hinge on LNG fuel price vs conventional fuel price. LNG is typically priced in energy units (MMBtu or per ton of LNG) and its cost relative to fuel oil can fluctuate regionally and over time. In many cases over the past decade, LNG has been competitive or cheaper per unit of energy than marine gasoil (MGO) or very low sulfur fuel oil, especially in regions with abundant natural gas. As mentioned, early 2024 saw LNG bunker fuel at major hubs like Rotterdam and Singapore selling at a discount to VLSFO, creating direct fuel cost savings for LNG-fueled ships. However, in late 2021 and much of 2022, global gas prices spiked to record highs (due to supply disruptions and post-pandemic demand, exacerbated by the Russia-Ukraine crisis). During that period, LNG fuel could be significantly more expensive than oil-based fuel, eroding the economic advantage. Thus, LNG-fueled ship operators must manage fuel price risk, potentially via hedging or long-term contracts for LNG supply.

Despite volatility, there are structural factors that can favor LNG’s economics: many countries are investing in LNG liquefaction and bunkering capacity, increasing supply. Additionally, LNG as a fuel avoids some costs associated with oil fuels – for example, ships can forego installing exhaust scrubbers (which themselves cost several million dollars plus ongoing maintenance) since LNG is sulfur-free. Maintenance of LNG engines can be slightly different (they run cleaner so engine oil stays usable longer, but the equipment is more complex in areas like cryogenics), with some reports indicating comparable or modestly lower maintenance costs relative to traditional engines fitted with emissions aftertreatment.

Infrastructure and logistics: For an owner considering LNG, one economic question is the availability of fuel where the ship will trade. LNG bunkering infrastructure, while expanding, is still concentrated in certain key ports (Europe, East Asia, North America, Middle East). Ocean-going ships often plan their routes and fuel stops accordingly. If a ship needs to deviate or operate in regions without LNG, it might have to carry sufficient LNG for round trips or use fallback fuel, which complicates operations. Over time this concern is easing, as by 2024 nearly 200 ports globally offer LNG bunkering and additional projects are underway. In practice, major trade routes (Asia-Europe, trans-Pacific, etc.) now have multiple LNG fueling options. Owners typically establish agreements with fuel suppliers or even co-invest in bunkering infrastructure to secure reliable supply. Some shipping lines have formed partnerships with energy companies (e.g., long-term charters of LNG bunker vessels or off-take agreements) to ensure competitive and steady LNG availability, which improves cost predictability.

Charter premiums and market value: In the charter market, LNG-fueled vessels can command a premium due to their ability to trade without emissions restrictions. For instance, some commodity producers and charterers (like mining companies or oil majors) prefer dual-fuel vessels to move their cargo, aligning with their own sustainability commitments. This means an LNG-capable ship might enjoy higher demand or better time-charter rates compared to a similar non-LNG ship, all else equal. Industry analysis in recent years indicated charter rate premiums on the order of 10–20% for LNG-fueled newbuilds in certain segments (notably large container ships and tankers). Additionally, secondhand values of dual-fuel ships have shown resilience – investors see them as less likely to face obsolescence under green regulations, thus protecting asset value. These factors can help an owner recover the initial investment over the vessel’s life.

Compliance costs and emissions markets: An emerging economic consideration is carbon pricing. Regions like the European Union are incorporating shipping into emission trading systems and carbon taxes. LNG, with its lower CO₂ emissions per ton of fuel burned, effectively would incur lower carbon costs than fuel oil for the same transport work. If, for example, a carbon price of $100/ton CO₂ is applied, a ship that cuts CO₂ by 20% using LNG would save substantial money annually on carbon allowances. This dynamic was highlighted as the EU’s ETS for maritime (starting 2024–2026) draws near. Furthermore, the IMO is discussing market-based measures that may put a price on carbon or encourage low-carbon fuels – again a scenario where LNG could offer cost advantages over HFO/MGO in the medium term. Shipowners are thus doing scenario analyses; many see LNG fueling as a hedge against future carbon costs.

Operational requirements and training: From an economic standpoint, companies must also consider the costs of crew training and new operating procedures for LNG. Crew members need specialized training (per the IGF Code requirements) to handle LNG safely – this means additional training expenses and sometimes hiring or retaining crew with the necessary certification. However, many maritime training centers now offer LNG handling courses, and costs have become more routine. Onboard, LNG systems add some complexity to operations (e.g., managing tank pressure, coordinating bunkering), which can mean slightly higher man-hour inputs or the presence of additional gas handling personnel during bunkering. Leading companies have addressed these by developing comprehensive operating manuals and leveraging digital systems to monitor fuel systems, keeping additional operating costs minimal.

In sum, the economics for LNG ocean-going vessels involve a classic investment trade-off: higher initial cost in exchange for lower ongoing fuel and compliance costs and potentially higher revenues/asset value. Numerous studies have concluded that on certain high-usage routes (like Asia-Europe container trades or big tanker routes), LNG dual-fuel vessels can achieve a favorable total cost of ownership, especially under stricter environmental cost regimes. Nonetheless, these economics are sensitive to fuel price differentials and regulatory developments. Shipowners often weigh LNG against other compliance options (like very low sulfur oil plus scrubbers, or newer alternatives like methanol fuel or even future hydrogen-based fuels). As of 2024, the order trends suggest that many conclude LNG is the most mature and economically viable solution for immediate emissions compliance and an interim decarbonization step.

Environmental Impact

Switching from conventional marine fuels to LNG brings clear environmental improvements, particularly in the domain of air quality and pollutant emissions. At the same time, it introduces new considerations, such as methane emissions, in the context of global warming. Here we review the environmental impacts of LNG-fueled ocean-going vessels across various dimensions:

Air pollution and health impacts: LNG combustion virtually eliminates certain pollutants compared to heavy fuel oil (HFO):

• Sulfur Oxides (SOₓ): LNG contains no sulfur. Therefore, LNG-fueled engines emit negligible SOₓ – on the order of 99% less than an HFO-burning engine. This is crucial because SOₓ from ships contribute to acid rain and respiratory problems in humans. In coastal areas and ports, the elimination of sulfur emissions has a direct positive effect on air quality. Even compared to 0.5% sulfur fuels (VLSFO), LNG’s sulfur advantage is significant, as even VLSFO still emits some SOₓ whereas LNG emissions are near zero.

• Particulate Matter (PM): The combustion of LNG produces extremely low particulate emissions. Without heavy hydrocarbons and sulfur in the fuel, formation of soot and sulfate particulates drops dramatically. Studies and engine tests show particulate matter reductions on the order of 90–99% relative to diesel fuel. Crew members and port communities thus benefit from cleaner exhaust – less visible smoke, and far fewer fine particles that can penetrate lungs. This is a key health benefit in ports that have implemented LNG ferry or tug services; for example, some Scandinavian ferry operators noted markedly clearer air around terminals after switching to LNG.

• Nitrogen Oxides (NOₓ): NOₓ emissions are a more complex picture, as they depend on engine technology. However, gas engines often achieve very large NOₓ reductions. In a typical lean-burn Otto-cycle dual-fuel engine, NOₓ can be cut by 85–90% compared to a diesel engine on oil fuel. This is because peak combustion temperatures are lower and the premixed combustion is cleaner. Such performance allows many LNG-fueled ships to meet IMO Tier III NOₓ requirements without needing add-on systems like SCR (Selective Catalytic Reduction). In contrast, a standard diesel engine would require urea-based SCR or exhaust gas recirculation to reach the same NOₓ levels. High-pressure dual-fuel engines, which operate on the Diesel cycle, produce NOₓ closer to a diesel baseline when in gas mode (since combustion is similar in character). Those engines typically incorporate exhaust solutions (e.g., exhaust gas recirculation as MAN ME-GI engines do) to ensure compliance. Overall, across the LNG-fueled fleet, NOₓ emissions are significantly reduced, which helps combat ozone formation and smog in port cities and coastal regions.

• Other air toxins: LNG’s cleaner combustion also means negligible emissions of other toxic components present in residual fuels, such as vanadium, nickel, and other heavy metals or polyaromatic hydrocarbons. It also emits far lower levels of black carbon (soot), which is not only a health hazard but also a climate forcing agent, particularly impactful in the Arctic. The use of LNG could thus contribute to reducing black carbon deposition on ice if LNG ships operate in polar routes.

Greenhouse gas emissions: On a “tank-to-wake” basis (i.e., fuel burned on the ship), LNG yields approximately 20–25% lower carbon dioxide emissions than the combustion of marine oil for the same energy output. This is due to the higher hydrogen-to-carbon ratio of methane (CH₄) versus oil’s hydrocarbons. For example, burning 1 ton of LNG emits about 2.75 tons of CO₂, whereas 1 ton of HFO emits around 3.15 tons CO₂ (plus the fact LNG engines may be slightly more efficient in converting fuel to propulsion in some cases). When factoring in the overall supply chain (“well-to-wake”, including production and transport of the fuel), studies commissioned by industry groups have found net GHG reductions in the range of 10–20% for LNG relative to oil-based fuels, when using modern engine technology and accounting for some methane slip.

However, the benefit and narrative around GHG emissions is complicated by methane slip and supply-chain methane leakage. Methane is a potent greenhouse gas (with a global warming potential over 20 years about 80 times that of CO₂). If even a few percent of the methane in LNG leaks or is unburned, it can diminish or even negate the CO₂ reduction benefit in terms of total climate impact. Early-generation dual-fuel engines (especially some older medium-speed 4-stroke models) had higher methane slip levels, raising concerns in environmental assessments. The industry has responded by improving engine tuning, fuel injection timing, and adding oxidizing catalysts in some cases to tackle methane in the exhaust. For instance, newer low-pressure dual-fuel engines with advanced control (such as X-DF engines with Intelligent Control by Exhaust Recycling) report methane slip reductions of 50% compared to their predecessors. High-pressure dual-fuel engines inherently have minimal slip. As a result, many newer LNG ships have significantly narrowed the gap, ensuring that overall GHG emissions are indeed lower than if burning oil.

On the upstream side, the natural gas industry is under scrutiny to tighten methane emissions during gas production, liquefaction, and transport. Major LNG suppliers have voluntary programs to detect and fix leaks and to implement more efficient practices. From a shipping company perspective, one way to address the climate aspect is to purchase certified “green LNG” or carbon-neutral LNG where the supplier offsets or biomethane is blended. Some LNG bunkering deals now include guarantees of origin or credits to account for methane emissions, essentially ensuring that the fuel used has a verified climate advantage. Additionally, some operators have experimented with blending liquefied biogas (bio-LNG) into the fuel to directly cut net carbon emissions. For example, there were pilot bunkerings of bio-LNG in Rotterdam and Scandinavia where a few percent of the LNG was renewable, immediately trimming the carbon footprint.

In summary, when properly managed, LNG as fuel provides a net GHG reduction relative to oil fuels, albeit a modest one (often cited around 20% better). The reduction is meaningful in the near term as shipping seeks any available cuts, but it alone is not sufficient for long-term climate goals like 50% or greater reduction. The industry acknowledges this and views LNG-fueled ships as part of a “pathway” – the immediate GHG benefit is coupled with the potential to transition to carbon-neutral LNG substitutes in the future without major modifications to the ships. This “LNG pathway” concept is a central environmental selling point: investing in LNG-capable tonnage now establishes a foundation that can utilize bio-methane or synthetic methane (from renewable power and captured CO₂) once those become viable at scale, thereby potentially achieving very low or zero lifecycle emissions by 2030–2050.

Operational environmental benefits: Beyond emissions, LNG fuel offers some other environmental advantages:

• No sludge or waste oil: Heavy fuel oil use generates sludge (unburnable remnants, tank sediments, etc.) that must be stored on board and discharged at port facilities. LNG leaves no such residues. This simplifies waste handling and eliminates the risk of improper waste oil discharge at sea. Engine lube oil in LNG engines also remains cleaner, extending its life and reducing frequent oil changes.

• Lower risk of oil spills: An LNG spill, while dangerous due to flammability, does not cause the kind of persistent pollution that an oil spill does. LNG will evaporate and dissipate if released, leaving no lasting contamination in water or soil. As such, an LNG-fueled ship poses virtually no risk of oil pollution from fuel (though of course its cargo, if oil, is another matter). This is a notable advantage for cruise ships or others operating in ecologically sensitive areas – LNG bunkers do not threaten the environment with chronic contamination.

• Noise and engine performance: Some LNG engines (particularly 4-stroke) are observed to run slightly quieter and with less vibration when in gas mode compared to diesel mode. While not a primary environmental factor, reduced noise pollution could benefit marine life in some situations and improve crew comfort.

Environmental challenges: Despite the benefits, it’s important to recognize challenges:

• Methane slip and leaks: As discussed, the primary environmental concern with LNG is methane. Regulators and future emissions rules may specifically target methane emissions from ships. The IMO is evaluating how to incorporate methane into its efficiency and carbon intensity ratings. If standards tighten, ships will need to demonstrate low methane slip perhaps via engine certification or adding oxidation catalysts. Owners of LNG ships are keeping an eye on this – ensuring their equipment meets best available standards to avoid any regulatory non-compliance on methane.

• Supply chain emissions variability: If LNG is sourced from a supplier with poor methane management, the overall climate benefit could be less. There is growing pressure for transparency in LNG’s upstream emissions. In response, several large gas producers have started providing “GHG intensity” data for their LNG. Shipping lines may increasingly choose suppliers with lower lifecycle emissions or require offsets as part of contracts.

• End-of-life and conversion: Eventually, if shipping shifts to zero-carbon fuels (like hydrogen or ammonia), there is a question of what happens with LNG-fueled ships. Some might be converted to other fuels – for instance, there is research into converting dual-fuel engines to ammonia or methanol. In 2023, one of the early LNG-fueled tugs in Japan was selected for conversion to ammonia fueling as a demonstration. In the meantime, however, LNG ships are likely to operate for decades, and managing their decommissioning or repurposing is a future consideration (not an environmental issue per se during operations, but relevant to lifecycle sustainability).

Overall, LNG-fueled ocean-going vessels offer a significant reduction in local pollutants that has an immediate positive impact on human health and ecosystems. They also contribute to greenhouse gas mitigation, though more modestly, and come with the caveat of needing diligent control of methane emissions. Industry stakeholders, including environmental organizations, generally recognize LNG’s pollution reduction merits but have varied opinions on its GHG merits—some embrace it as a pragmatic step forward, while others caution that it is not a long-term climate solution. This report’s findings underscore that in the 2020s LNG is playing a crucial role in cleaning up emissions from the global fleet, and with improvements and transitions to renewable variants, it can remain an important part of shipping’s environmental strategy.

Regulatory and Compliance Framework

From design approval through operational procedures, LNG-fueled ocean-going vessels are governed by a comprehensive framework of international and local regulations. These rules ensure safety in handling LNG and also influence the adoption of LNG by setting emissions requirements. Key regulatory aspects include:

IMO IGF Code: The International Code of Safety for Ships Using Gases or Other Low-Flashpoint Fuels (IGF Code) is the cornerstone for LNG ship design and operation. Adopted by the International Maritime Organization and in force since 2017, the IGF Code applies to all newbuild ships using fuels like LNG that have a flashpoint below 60°C. It covers everything from fuel tank location and structure, to fire protection, gas detection, ventilation, electrical equipment in hazardous zones, and emergency shutdown arrangements. For example, the IGF Code mandates that LNG fuel tanks be located such that in a grounding or collision they are protected (typically not too close to the outer shell or bottom). It also requires dual piping or equivalent safety for any gas lines in enclosed spaces, redundancies in the fuel supply system, and independent venting systems. Compliance with the IGF Code is verified by classification societies on behalf of flag states. Essentially, any ocean-going LNG vessel must be built to these standards and carry an International Certificate of Fitness for gas-fueled ship operation. The IGF Code is a living document; work is ongoing at IMO to extend it to cover other fuels (like methyl/ethyl alcohols, ammonia, etc.), but LNG was the primary focus of the initial code, benefitting from the earlier IGC (gas carrier) Code experience.

Class society rules: In parallel, classification societies (such as DNV, Lloyd’s Register, ABS, Bureau Veritas, etc.) have developed their own rules for gas-fueled ships, which align with or sometimes go beyond the IGF Code. Ships get class notations like “GF” (Gas Fueled) or similar to indicate compliance. Class rules provide detailed guidance on engineering aspects – for example, material standards for cryogenic service, calculations for tank sloshing loads, ventilation capacity in machinery spaces, etc. They also set testing and survey regimes (like how often certain valves or safety systems must be inspected). Thanks to these rules, there is now a decade of experience in safely operating LNG-fueled ships with no major incidents.

Crew training and operating procedures: The IMO’s Standards of Training, Certification and Watchkeeping (STCW) convention has been amended to include training requirements for seafarers on gas-fueled ships. Crew must undergo specialized training courses (basic and advanced levels for gas fuel handling) and receive endorsements on their certificates. Ports and companies also conduct emergency drills (for example, simulating an LNG leak response). These training and procedure requirements are effectively regulatory, often enforced by Port State Control inspections or charterer vetting. Without properly certified crew, an LNG-fueled ship could be detained or not allowed to bunker. Many countries have also issued guidelines or regulations for LNG bunkering operations in their waters – these cover how to obtain permits for bunkering, safety zones to establish during bunkering (clearing people away within a certain radius), and coordination with port authorities and local emergency services.

Emission regulations compliance: As mentioned, LNG-fueled ships inherently comply with the 2020 global sulfur cap (MARPOL Annex VI) and the 0.1% sulfur limits in Emission Control Areas (such as the North Sea, Baltic Sea, North American coasts, and Caribbean ECA zones). So from a sulfur regulation perspective, they have a clear advantage. For NOₓ, MARPOL Annex VI Tier III standards apply to ships operating in NOₓ Emission Control Areas (currently North America and US Caribbean, with the North Sea and Baltic joining in 2021 for new builds). LNG engines can meet Tier III either inherently (low-pressure engines) or with engine-integrated measures, meaning LNG ships can travel in these zones without additional modifications. The ship’s EIAPP Certificate (Engine International Air Pollution Prevention) will reflect compliance based on engine tests either on pure gas or dual fuel mode.

For greenhouse gases, IMO’s current approach is the Energy Efficiency Design Index (EEDI) for new ships and the Carbon Intensity Indicator (CII) for existing ships’ operations. LNG-fueled ships benefit under EEDI because the formula assigns a lower carbon factor to gas fuel. This means an LNG-fueled newbuild gets credit for lower theoretical CO₂ per ton-mile, helping it meet required EEDI reduction targets. In some cases, a design that would not pass EEDI on diesel may pass on LNG. The CII (operational carbon intensity grades A–E) will indirectly favor LNG use as well, since emitting less CO₂ per distance improves the CII. If a ship can demonstrate 20% less CO₂ by using LNG, its CII rating will be better, which from 2024 onward can have regulatory consequences (poor CII ships must improve or risk penalties/limitations). Therefore, ship operators using LNG are somewhat advantaged in complying with these climate-related regulations in the short term. However, as noted, methane is not yet explicitly in these rules – there is discussion of incorporating methane and nitrous oxide in future revisions of IMO’s climate measures.

Port and flag state policies: On top of international regulations, various national and port-level rules encourage LNG. For example, the European Union’s (now superseded) Alternative Fuels Infrastructure Directive had set targets for core TEN-T ports to have LNG bunkering by 2025, which has influenced numerous port investments in LNG facilities. This directive was updated into the Alternative Fuels Infrastructure Regulation (AFIR) in 2023, continuing support for LNG infrastructure alongside electrification and other fuels. Some EU countries have subsidized pilot LNG vessels or infrastructure (Spain, France, the Netherlands, etc., through programs like Connecting Europe Facility). Singapore, aiming to be an LNG bunkering hub in Asia, rolled out co-funding schemes for early adopters and co-developed standards for LNG bunkering procedures (Singapore’s Technical Reference for LNG bunkering eventually informed ISO standards). The Maritime and Port Authority of Singapore also offers a 10% green port dues incentive for LNG-fueled vessels as part of its Green Ship Programme, which effectively rewards ships that use cleaner fuels when they call at Singapore.

China’s major ports (Shanghai, Guangzhou, etc.) have also begun LNG bunkering services and may introduce incentives as part of emission reduction plans in their coastal areas. In North America, the US Coast Guard has issued comprehensive regulations and policy letters on LNG bunkering safety, given the introduction of LNG-fueled container ships and cruise ships in U.S. ports. The United States government through MARAD (Maritime Administration) provided funding support for some LNG-ready and LNG-fueled vessel projects (like grants for converting ferries to LNG or building LNG tugs) to pilot the technology.

Industry standards and best practices: Beyond formal regulations, the industry has collaboratively developed standards that guide LNG fuel usage. ISO 20519 is an international standard for LNG bunkering transfer systems, covering the equipment and interfaces for ship-to-ship and shore-to-ship LNG fueling. Following such standards is often a de facto requirement by charterers or port authorities for allowing bunkering operations. The Society for Gas as a Marine Fuel (SGMF) and SEA-LNG coalition have published guidelines and checklists for safe bunkering, crew training, and emergency response. Many LNG-fueled vessel operators participate in these forums to share experiences and continuously improve safety and reliability. Classification societies also often require risk assessments (HAZID/HAZOP) during the design of an LNG-fueled ship and its bunkering arrangements, which, while technical, become part of the compliance landscape ensuring all risks are mitigated to as low as reasonably practicable.

Future regulatory outlook: Regulations continue to evolve. IMO’s updated greenhouse gas strategy (agreed mid-2023) calls for net-zero emissions from international shipping by around 2050, with interim checkpoints (like ~30% reduction by 2030, ~70% by 2040, compared to 2008). This does not outlaw fossil LNG, but it does imply that over time ships will need to further decarbonize their fuel mix. We may see measures such as a low-carbon fuel standard or GHG intensity fuel mandate – under which LNG could serve as a qualifying fuel if blended with bio-LNG or if paired with carbon capture, etc. The EU’s FuelEU Maritime regulation (starting 2025) will require gradually reducing the GHG intensity of fuels used by ships calling at EU ports. LNG initially helps a vessel comply (due to its lower CO₂), but by 2030 ships will likely need additional steps (biofuel blends or other fuels) to meet FuelEU limits. Thus, regulatory trends suggest that while LNG is an enabler for compliance now and in the near future, further innovation (like using renewable LNG or improving engine efficiency even more) will be needed to keep these ships in compliance long-term.

On the safety side, one can expect continued refinement of the IGF Code as more data from LNG operations is gathered. Thus far, LNG-fueled ships have had an excellent safety record, which validates the regulatory approach taken. Maintaining that record is paramount – a major incident could prompt tighter rules. Authorities also monitor boil-off and methane emissions; if methane slip remains a concern, we could see something analogous to a cap on methane emissions per engine (perhaps via revised IMO engine emission test cycles that account for unburned hydrocarbons).

In summary, LNG-fueled ocean-going vessels operate within a well-defined regulatory regime that addresses their safety and environmental performance. This regime has facilitated the growth of the sector by providing clear rules and reassurance to stakeholders. At the same time, as environmental policies become more ambitious, these vessels will need to leverage their built-in advantages (cleaner emissions) and possibly adapt through fuel blending or technology upgrades to remain at the forefront of compliance in the decades ahead.

Current Fleet Status and Industry Examples

The global fleet of LNG-fueled ocean-going vessels has transitioned from an experimental phase into a growth phase, with hundreds of ships in operation and many more on order. This section outlines the composition of the current fleet, recent growth trends, and notable examples of ships and companies driving LNG adoption.

Fleet size and composition: As of the beginning of 2025, there are approximately 640 LNG-fueled ocean-going ships in service worldwide (excluding LNG carrier tankers). These are spread across various segments:

• Container Ships: One of the fastest-growing categories, with dozens of large container vessels now running on LNG. Notably, CMA CGM, a French shipping line, has invested heavily – by 2024 it operated a fleet of LNG-powered ultra-large container ships (ULCS) including the 23,000 TEU CMA CGM Jacques Saadé and sister ships, which were the world’s first megaships of their size on LNG. Other major carriers like Hapag-Lloyd, MSC, and Cosco have also ordered LNG-fueled container ships in the 13,000–15,000 TEU range. By count, there are over 50 LNG container ships in operation, ranging from feeder size up to the ULCS class, with more than 100 on order. These ships often ply Asia-Europe routes where bunkering hubs like Singapore, Rotterdam, and Shenzhen are available.

• Oil and Chemical Tankers: LNG-fueled tankers include crude oil tankers (Aframax and even some VLCCs on order), product tankers, and shuttle tankers for offshore oil fields. For example, Shell and Sovcomflot collaborated on a series of LNG-fueled Aframax tankers (about 114,000 DWT) which have been trading since 2018, primarily carrying oil in Northern Europe and the Baltic where they can bunker in Rotterdam or Russian ports. These ships each have a large deck-mounted LNG tank and use dual-fuel two-stroke engines. There are also specialized shuttle tankers in the North Sea (operated by companies like Teekay) using LNG combined with volatile organic compound (VOC) recovery systems to further cut emissions. As of 2024, roughly two dozen LNG-fueled oil tankers were in service, and many more (including several large crude tankers and many product tankers) are on order as the tanker sector embraces LNG for compliance with ECA rules and forthcoming carbon intensity norms.

• Bulk Carriers: Bulkers have been slower initially, but momentum is building. The mining company BHP, in partnership with shipowner Eastern Pacific, introduced five LNG-fueled Newcastlemax bulk carriers (around 210,000 DWT each) in 2022 to transport iron ore from Australia to China. These vessels bunker LNG in Singapore and have demonstrated the viability of LNG on long-haul bulk trades. Additionally, charterers like Rio Tinto and Vale have shown interest in LNG dual-fuel bulkers. By 2024 there were only a handful (under 10) large LNG-fueled bulk carriers in operation, but orders are increasing as charterers push for greener shipping of dry commodities. Numerous Kamsarmax and Capesize bulkers with LNG capability are on order in Chinese and Japanese yards for delivery through 2025–2026.

• Car Carriers (PCTCs): The car carrier segment has seen significant adoption of LNG. Vehicle carrier operators such as UECC (United European Car Carriers) were early adopters, with medium-size car carriers like Auto Eco and Auto Energy (3800-vehicle capacity, delivered 2016) running on LNG in the Baltic and North Sea. Building on that, newer large Pure Car and Truck Carriers (PCTCs of 7000+ vehicles capacity) are being built with LNG fuel to meet tight emissions standards on global routes. For instance, Japanese lines like NYK and K Line have several LNG-fueled PCTCs delivered or on order, and the Grimaldi Group in Italy is deploying LNG on its new roll-on/roll-off cargo ships. By 2024, around 10–15 LNG-powered car carriers were in service, with at least triple that number on the orderbook. This segment is motivated by both ECA compliance (many car carriers frequent U.S. and European ports) and pressure from automobile manufacturers for cleaner logistics.

• Cruise Ships and Ferries: The cruise industry made headlines with LNG in 2018 when Carnival Corporation introduced AIDAnova, the world’s first LNG-fueled cruise ship. Since then, multiple large cruise ships have entered service on LNG, including Carnival’s Mardi Gras, Costa Smeralda, P&O Iona, Disney Cruise Line’s Disney Wish, and Royal Caribbean’s upcoming LNG-powered vessels. These ships bunker mainly in European ports and at LNG cruise terminals (like Port Canaveral, USA, which established LNG bunkering specifically to fuel cruise ships). LNG virtually eliminates sulfur and soot from cruise ship exhaust, an important factor for public perception in tourist destinations. By the end of 2024, around 8–10 large cruise ships were LNG-fueled, and many more (over 20) are under construction for deliveries into the late 2020s, indicating that LNG will become a standard option for new cruise tonnage. In the ferry sector, LNG use started early in Norway (with car ferries such as Glutra in 2000, and many Norwegian coastal ferries and car-passenger ferries switching to LNG through the 2000s). Today, LNG-fueled ferries operate in Scandinavia, the Baltic, around the British Isles (e.g., the Isle of Man ferry Mannox on order), and parts of Asia. These vessels are often medium-sized and use pure gas engines, providing cleaner transport on short routes. There are also high-speed RoPax ferries in Asia (e.g., in Taiwan) using LNG. The cumulative number of LNG ferries worldwide is on the order of a few dozen, with continued newbuilding particularly wherever governments encourage lower ferry emissions.

• Offshore and Others: LNG has been adopted in some offshore service vessels (OSVs) – notably platform supply vessels working in the North Sea for Norwegian oil companies, which were among the earliest users of LNG in the 2010s to reduce emissions in sensitive Arctic environments. Companies like Equinor (Statoil) championed LNG PSVs, and now there are several such vessels in operation. Additionally, a few dredgers (e.g., DEME’s Minerva) and specialized ships like crane vessels have been built with LNG fuel capability. These illustrate that even niche vessel types can integrate LNG where it aligns with project or environmental requirements.

Geographical deployment: Initially, Europe (especially Norway and the North/Baltic Sea region) led LNG fuel adoption due to early environmental regulations and government support. Today, the deployment is truly global:

• In Asia, major bunkering centers such as Singapore, Busan (Korea), Shanghai and Zhoushan (China), and ports in Japan are regularly refueling LNG-fueled ships. Asian shipping companies are increasingly building LNG-fueled vessels for long-haul routes and also for regional trades. Japan in particular has taken up LNG for coastal shipping (fueling tugs, ferries, and even a coastal tankers) as part of a national program to cut shipping emissions.

• In Europe, the North Sea and Baltic remain key areas – for example, an LNG-fueled ship can travel from the Baltic, through the North Sea, and across the Atlantic with multiple opportunities to refuel (Zeebrugge, Rotterdam, and the Iberian Peninsula are all LNG bunkering points). The Mediterranean is also coming up to speed: the port of Marseille in France has an LNG bunker vessel to serve Mediterranean trades, and Italy and Spain both have increased LNG bunkering activity.

• In North America, the adoption was initially slower due to cheaper low-sulfur fuel availability, but it’s picking up. The United States has a few noteworthy examples: the two LNG-fueled container ships operated by TOTE between Jacksonville, Florida and Puerto Rico (the Isla Bella and Perla del Caribe launched in 2015–16) were among the first ocean-going LNG containerships. Also, several new LNG-fueled PCTCs (vehicle carriers) started calling at U.S. ports delivering cars with LNG as fuel, bunkering at Jacksonville (JAX LNG facility) or at West Coast ports where LNG bunkering is emerging (like in Vancouver, Canada for PCTCs serving the Pacific). Cruise ports like those in Florida now handle LNG bunkering regularly for cruise liners. In Canada, aside from coastal ferries in British Columbia using LNG, an innovative project is underway to use LNG in Great Lakes bulk carriers (with one such vessel already converted to dual-fuel and trading on the St. Lawrence Seaway).

• In the Middle East, Qatar has been a proponent both as a fuel supplier and user: Qatar Petroleum (now QatarEnergy) ordered over 100 new LNG carriers for its LNG export expansion, all with the latest dual-fuel engines (though those are LNG carriers, not in our main count, it highlights the country’s commitment). Additionally, UAE’s port of Jebel Ali and Oman’s Port of Sohar are gearing up for LNG bunkering to serve the many LNG-fueled ships transiting the region.

• Other regions like Australia and South America are still nascent in LNG bunkering, but some developments exist (Australia uses LNG-fueled platform supply vessels on the North West Shelf, and Brazil is exploring LNG for coastal shipping). As more ships come online, the network of LNG bunkering is expected to extend to more ports in these regions.

Recent growth and orderbook: The pace of deliveries of LNG-fueled ships hit a record in 2024, with roughly 160–170 new LNG-powered vessels delivered that year alone. This influx was led by container ships and car carriers, which had placed many orders in 2021–2022. The overall orderbook for LNG-fueled vessels (non-LNG carriers) now stands above 400 ships to be delivered in the next few years. This means the operational fleet could roughly double again by 2028, potentially reaching around 1,200 vessels or more, as forecast by industry coalitions. Many shipyards report that a significant portion of their current workload is for alternative-fuel capable ships, with LNG being the dominant choice in the near term. For example, all of the large container ships ordered by CMA CGM in recent years are LNG dual-fuel, and other container lines like Hapag-Lloyd have split some orders between LNG and methanol fuel, indicating a diversified approach. Tanker owners like AET and Shell-affiliated contracts have new LNG dual-fuel VLCCs and Suezmax tankers coming. Bulk owner Eastern Pacific has more LNG bulkers coming. Essentially, across all main vessel types, LNG is represented in the orderbook, reflecting broad acceptance.

Industry players and examples: A few examples of industry leaders:

• Shipping Companies: CMA CGM (France) – one of the largest operators of LNG-fueled ships, with a dedicated “Energy Transition” strategy centered on LNG; MSC (Switzerland) – the world’s largest container line, which after an initial pause is also ordering some LNG-fueled newbuilds; Carnival Corporation (USA/UK) – leading cruise lines under its umbrella pioneering LNG in cruise sector; Qatari LNG transport (Qatargas) – influencing LNG carrier and ship fuels; Eastern Pacific Shipping (Singapore) – privately-owned shipowner with one of the largest dual-fuel fleets spanning containers, bulkers, tankers, and even car carriers; Shell (UK/Netherlands) – not only chartering LNG-fueled tankers and carriers but also a major LNG bunker fuel supplier through its network; Sovcomflot (Russia) – early adopter in tankers and ice-breaking LNG-fueled ships for Arctic operations.

• Engine and Technology Providers: MAN Energy Solutions and Wärtsilä are two primary engine makers enabling LNG propulsion (MAN with ME-GI low-speed and 4-stroke DF engines, Wärtsilä with 4-stroke DF and in partnership with WinGD for X-DF low-speed). Their continuous R&D has improved performance and reduced methane emissions. Companies like Rolls-Royce (mtu brand) and Caterpillar (MAK) also provide medium-speed gas engines for smaller ship types. Tank and system manufacturers (like GTT for membrane tanks, or TGE, Wärtsilä Gas Systems, etc., for Type C tanks and fuel systems) are essential suppliers.

• Bunker Fuel Suppliers: Major oil & gas companies – Shell, TotalEnergies, BP, and bunker specialists like Titan LNG, Gasum (Nordic), and Pavilion Energy (Singapore) – have set up LNG bunker delivery services. They often own/operate the LNG bunkering vessels discussed in the next section. Their role has been crucial in building confidence that fuel will be available wherever LNG ships sail.

• Ports and Infrastructure: Ports such as Rotterdam, Singapore, Busan, and Fujairah (UAE) have positioned themselves as LNG bunkering hubs, investing in terminals and bunker vessels. Rotterdam’s Gate Terminal and Singapore’s SLNG terminal are examples of large import facilities now also serving bunkering needs. Smaller-scale LNG distribution is also growing (truck-to-ship bunkering is common in ports like Shanghai and Hamburg for certain vessels, though as volumes grow, ship-to-ship is preferred).

Notable vessel examples:

• CMA CGM Jacques Saadé (Container Ship): Entered service in 2020 as the flagship of CMA CGM’s nine 23,000 TEU LNG-powered giants. It operates on the Asia-Europe trade. It has a large 18,600 m³ membrane LNG tank enabling round-trip voyages. These ships helped prove that even the largest ships can reliably use LNG. They bunker via dedicated bunker vessels like Gas Agility in Europe.

• Hapag-Lloyd’s “Berlin Express” class (Container Ships): An example from 2023–24 of 13,000 TEU ships with dual-fuel engines, to be deployed on transpacific routes. They highlight that multiple carriers are now adding LNG tonnage.

• Pacific International Lines (PIL) “8000 TEU series” (Container Ships): PIL, a Singapore-based carrier, recently took delivery of LNG dual-fuel mid-size container ships, showing that even medium-sized operators consider LNG to maintain competitiveness and compliance in Asia.

• SCF Laika and sister Aframax tankers: Part of Sovcomflot’s “Green Funnel” series delivered 2018–2019, each 114k DWT crude/product tanker with a 1,100 m³ LNG tank. They trade primarily in Northern Europe and have consistently used LNG, with Shell providing bunkers. They demonstrated the feasibility in tankers and influenced others to follow.

• BW Magna (LNG-FSRU and transport): While LNG carriers are beyond our main scope, the interesting aspect is BW Group ordering LNG carriers with intent for them also to serve as bunkering tenders if needed – blurring the lines and showing synergy in the LNG supply chain.

• Costa Smeralda (Cruise Ship): A 180,000 GT cruise ship for Costa Cruises (Carnival Corp) launched in 2019, sailing in the Mediterranean on LNG. Its sister Costa Toscana and others bring LNG to the mainstream cruise market in Europe. Carnival has gone further to secure LNG bunker supply deals in ports like Barcelona and Marseille to fuel these ships.

• Disney Cruise Line’s LNG ships: Disney’s newest cruise liners (Disney Wish, Treasure) are LNG-fueled, indicating how even companies with strong family-friendly brands see marketing value in cleaner fuel (no smoke over the decks, better environmental image). They bunker in Port Canaveral, which had to adapt to accommodate LNG fueling via a dedicated barge.

• TOTE Orca Class (Container/RORO): The Isla Bella and Perla del Caribe, although in a niche Jones Act trade, were trailblazers in 2015 for using LNG on a commercial cargo service (between Florida and Puerto Rico). They showed significant emissions cuts, which was important for compliance in U.S. Caribbean ECAs. Their example is often cited in North America.

These examples and trends demonstrate that LNG-fueled ocean-going vessels are no longer experimental outliers; they form a growing, diversified part of the world fleet. With solid operational experience accrued (several million cumulative operating hours on LNG by 2024) and a supportive economic/regulatory case, this segment is expected to continue expanding in the near term. The following sections will explore the supporting ecosystem – namely, the LNG bunkering vessels that supply these ships – and the port support vessels that are also turning to LNG to improve local emissions.

LNG Bunkering Vessels

As the population of LNG-fueled ships has grown, so too has the need to efficiently deliver LNG to them. LNG bunkering vessels (often abbreviated LNGBVs) have become a vital component of the supply chain, enabling ship-to-ship refueling of LNG at sea or in port. These vessels are essentially small-scale LNG tankers outfitted specifically for transferring fuel to other ships, with enhanced maneuverability and safety systems for bunkering operations. This section covers the specialized technology of LNG bunkering ships, their economic and operational roles, environmental aspects of their use, regulatory considerations for bunkering operations, and the current global fleet and examples of such vessels in service.

Figure: The LNG bunkering vessel Gas Agility (center) refueling the LNG-powered ultra-large container ship CMA CGM Jacques Saadé (left) at the Port of Rotterdam. Gas Agility, delivered in 2020 and at 18,600 m³ capacity, is one of the world’s largest LNG bunkering vessels, enabling efficient ship-to-ship fuel transfer for large ocean-going vessels.

Technology and Design of Bunkering Vessels

LNG bunkering vessels are designed to load LNG from a supply terminal and then deliver it to client vessels with precision and safety. Key features of their technology include:

• Cargo Tanks: Bunkering vessels typically carry LNG in cylindrical Type C pressure tanks. These are durable, thick steel tanks that can withstand pressure buildup (usually allowing about 3–4 bar pressure) and thus can hold LNG with minimal boil-off for extended periods – useful since bunkering schedules can vary. The size of bunkering vessels ranges widely: early models were often 5,000–7,500 m³ capacity (suitable for fueling multiple smaller ships or a couple of large ships per trip). More recently, larger bunkering ships of 10,000–20,000 m³ have been built to serve very large fuel consumers. For instance, Gas Agility and its sister Gas Vitality (operated by TotalEnergies in Europe) have 18.6k m³ capacity via membrane tanks, allowing them to fill mega-containerships in a single operation. Most bunkering vessels have two to four separate tanks to provide flexibility in delivery (they can manage different parcels or perform partial deliveries more easily than one giant tank).

• Transfer Equipment: The heart of a bunkering vessel is its cargo transfer system. This includes LNG transfer hoses (usually cryogenic hoses, 6 to 8 inches diameter, with quick connect/disconnect couplings) and in some cases rigid loading arms for side-by-side transfers. The bunkering vessel uses specialized cryogenic pumps to push LNG through the hose to the receiving ship’s tanks. A typical flow rate might be 100–300 cubic meters per hour for smaller vessels, up to 1000+ m³/hour on the largest bunkering ships – meaning they can complete bunkering of, say, 4,000 m³ in a matter of 4–5 hours under ideal conditions. The hoses have breakaway couplings that will seal off if the vessels drift beyond a threshold, preventing spills. Bunker vessels usually connect to the client ship via manifold connections compatible with ISO standards (ensuring any LNG-fueled ship can accept fuel from any standard bunker vessel). In addition, the bunker vessel is equipped with vapor return lines: as it pumps cold LNG into the receiving tank, vapor in that tank is displaced and sent back to the bunker vessel to manage pressure. The bunker vessel either reliquefies this vapor or uses it as fuel for its own engines, resulting in a closed-loop transfer that minimizes methane release.

• Maneuverability and Station Keeping: Many LNG bunker vessels are built with high maneuverability to come alongside ships that may be at anchor or berth. They often have twin propulsion systems, bow thrusters, and even dynamic positioning (DP) systems on larger ones. This allows them to hold position tightly during bunkering, which is critical for maintaining hose connections and safety. Some bunkering operations happen while the receiving ship is loading cargo or at anchor, so the bunker vessel must keep station in potentially crowded or wind-exposed harbors. DP2 capability (redundant dynamic positioning) is found on several modern bunker ships.

• Safety Systems: As floating LNG facilities, bunker vessels follow safety protocols similar to LNG carriers. They have comprehensive gas detection and emergency shutdown systems. If sensors detect LNG or vapor leaks, the transfer can be halted and valves closed automatically. Water spray or dry chemical firefighting systems are in place around transfer stations in case of an LNG pool fire (though LNG fires are handled mostly by letting them burn off while cooling surroundings). The crew of bunkering vessels is thoroughly trained in handling cryogenic cargo and coordinating with receiving ships on safety checks (like verifying electrical isolation, communication links, emergency release procedures before starting transfer). Bunkering vessels often carry a range of emergency equipment, including hydraulic power packs for emergency disconnection of hoses and portable gas detectors to aid the receiving ship’s crew during operations.

• Propulsion of Bunker Vessels: Interestingly, many LNG bunkering vessels use dual-fuel or pure gas engines themselves, effectively making them LNG-fueled ships as well. This is practical since they always carry LNG cargo which can be used as fuel (either via pressure build-up gas or small onboard vaporizers). For example, Engie Zeebrugge (an early 5,100 m³ bunker vessel in Europe) was built with dual-fuel engines so it could run on boil-off gas during voyages. This aligns with their mission by minimizing their own emissions while providing clean fuel to others.

• Multi-functionality: Some bunkering vessels are designed as multi-purpose: they can act as feeder carriers transporting LNG to small terminals or satellite storage facilities when not bunkering ships. A few can also carry other products in separate tanks (for instance, one design contemplated carrying LNG and conventional fuel oil in different compartments, serving as a hybrid bunker ship, although LNG-only vessels are more common). In the developing market, flexibility is useful to maximize utilization of these assets, as pure bunkering demand might not always fill their schedule initially. Over time as LNG bunkering demand grows, these vessels dedicate more fully to bunker operations.

Representative designs: Early examples include the 2017-built Engie Zeebrugge (now renamed Kairos after changing hands) which was stationed in Zeebrugge, Belgium, and served North Sea/Baltic ports; it has twin type C tanks and a bunker boom that connects to receiving ships. Another notable vessel is Coral Energy, which was originally a small LNG carrier but used for bunkering in some cases – showing that small LNG carriers (under ~10,000 m³) can sometimes double as bunker ships with some modifications.

Modern vessels like Gas Agility use membrane tanks (technological borrowing from large LNG carriers) to maximize capacity without a high profile, and are fitted with dual-fuel electric propulsion for fine control. A different approach is used in the USA: the first U.S. LNG bunkering vessel was actually a barge, Q-LNG 4000, delivered in 2020. It’s an articulated tug-barge (ATB) unit – a barge with 4,000 m³ LNG capacity paired with a dedicated tug, used for bunkering LNG cruise ships in Florida. ATBs can be a cost-effective solution in some cases (since barges are simpler without self-propulsion and U.S. Jones Act trade often uses barges).

Transfer modes: LNG bunkering vessels enable ship-to-ship (STS) transfer which has become the preferred mode for fueling large ships, as it can take place at anchor or at berth without the need for the receiving vessel to be next to a fixed terminal. STS bunkering can occur alongside (bunker vessel moored outboard of the ship at berth) or in some cases, underway at very slow speed (though that’s rare; most often both are stationary). Before these vessels were available, LNG-fueled ships relied on truck-to-ship bunkering or shore terminals. Trucks are feasible but inefficient for volumes above a few hundred cubic meters (multiple trucks needed, sequential unloading). Shore-based bunker stations (like in some ferry terminals in Norway or the dedicated cruise LNG bunker terminal in Port Canaveral) are useful but limited to that location. The advent of LNGBVs means a port can service ships anywhere within harbor limits or even outside the port. It also allows flexible scheduling – the bunker vessel can meet a ship at anchorage immediately when it arrives, rather than the ship having to go to a terminal slot.

Economic and Operational Role

LNG bunkering vessels represent a significant investment (a mid-size LNGBV can cost on the order of $30–50 million or more, depending on size and sophistication), so their economics are tied to the development of LNG as marine fuel and the utilization of these assets:

Demand and utilization: The primary driver for a bunkering vessel’s economics is the volume of LNG it delivers. As more LNG-fueled ships operate in its service area, demand for its fuel transfer services increases. Many early LNGBVs were commissioned under long-term charter or partnership between fuel suppliers and ship operators to ensure there was a baseline demand. For example, Gas Agility was chartered by TotalEnergies and positioned to specifically fuel nine CMA CGM mega-containerships on a regular schedule in Rotterdam; this guaranteed regular use. Similarly, FueLNG Bellina (a 7,500 m³ bunkering vessel in Singapore) had arrangements to fuel Shell-chartered tankers and other vessels calling Singapore. High utilization (performing frequent bunkering operations per month) is key to covering their operating costs and providing a return on investment.

Fee structure: Bunkering vessels typically earn revenue through a combination of fuel margin (if they are selling the LNG as well) and/or a service fee. Some are operated by fuel suppliers who both source LNG and deliver it, selling LNG to end users at an agreed price per ton including delivery. Others might be common carriers, delivering LNG that the receiving ship’s owner has procured separately (in which case a per-cubic-meter delivery fee or charter hire is charged). The business models vary: oil majors often integrated vertically (own the LNG, own or lease the bunker vessel, sell a package to the ship operator). Independent operators might charter the vessel to a supplier on a long-term basis.

Port integration and scale: Bunkering vessels can serve multiple ports in a region. For example, one vessel in the Baltics might load LNG at a terminal in Lithuania or Zeebrugge and then bunker ships in a range of ports around the Baltic and North Sea. This means their operation is often coordinated with multiple port authorities and they need bunkering permits in each locale. While this adds complexity, it increases their customer base. A well-placed LNGBV can monopolize a region’s LNG bunkering market if it’s the sole provider initially, but as demand rises often additional competitors or larger vessels join. Over time, multiple LNG bunker vessels may operate in large hubs (Rotterdam already has several, Singapore has licensed multiple operators, etc.), potentially leading to competitive pricing and more flexible scheduling for ship owners.

Cost considerations: Operating costs for an LNG bunkering vessel include crew, maintenance, boil-off management (if any LNG naturally evaporates, though usually minimal due to short voyages and pressure tanks), port fees, and fuel for its engines (which often comes from its cargo boil-off gas, making fuel cost low aside from lost cargo value). These vessels generally have small crews (they’re like small tankers, maybe 10–14 crew) and short voyages, so daily operating costs are modest relative to larger ships. The major cost is the amortization of the vessel’s capital cost. Therefore, ensuring sufficient throughput (volume delivered) is critical. In the initial years, some LNGBVs were underutilized as ship numbers were low, but many received financial support. For example, the EU co-funded a portion of the construction of several European bunker vessels under its environmental programs to kick-start the market.

Economic benefits to ports and shipping: For ports, having an LNG bunkering vessel service is a competitive advantage to attract the burgeoning traffic of LNG-fueled ships. Ports often facilitate the introduction by streamlining regulations or even co-investing. The presence of such vessels reduces the turnaround time for LNG-fueled ships (they don’t have to detour to an LNG terminal or rely on slow truck fueling). It thus makes LNG-fueled ships more operationally convenient, indirectly spurring more shipping companies to consider LNG. In essence, the bunkering vessel is an enabling infrastructure—like a mobile fuel station—that underpins the whole LNG fuel ecosystem.

Fleet development and scaling: Initially, smaller and fewer bunkering vessels made sense when ship numbers were limited. Now, with greater fuel demand, there is a trend to build larger capacity bunkering ships, which benefit from economies of scale (deliver more fuel per trip, reducing cost per unit delivered). However, bigger isn’t always better if the port has draft or size constraints or if customers are scattered. We see a mix: 18,000 m³ giants for mega hubs, but also smaller 3,000–8,000 m³ vessels for secondary ports or more niche operations (e.g., an LNG bunkering barge in a river port might be 1,000 m³ to fuel inland waterway vessels or ferries).

Flexibility and multi-fuel future: A thought on future-proofing: some LNG bunker vessel designs are being future-adapted to potentially handle other low-carbon fuels like ammonia or methanol if needed (though that’s a different chemical, the tanks and equipment would differ). But a number of analysts believe these bunker vessels could also in the future deliver bio-LNG or synthetic methane. Since those are molecularly the same as LNG, nothing would change technically – the same vessels can handle renewable versions of LNG, which means investing in an LNG bunkering fleet now is seen as a long-term bet that will pay off even as fuel content changes. So their economic life could extend well beyond fossil LNG if they pivot to renewables supply, giving confidence to investors.

Environmental and Safety Impacts

LNG bunkering vessels themselves contribute positively by enabling the environmental benefits of LNG for other ships. However, they also must be operated safely to prevent any LNG-related incidents. Key points on environment and safety include:

• Emissions from bunkering vessels: As mentioned, most LNGBVs use LNG fuel for their own propulsion or power, meaning they have a low emissions footprint (they too emit almost no SOₓ, minimal NOₓ, etc.). This is beneficial since these vessels often operate in port areas where emissions matters. The fact that bunkering vessels aren’t adding pollution while fueling “clean” ships helps ensure the overall environmental benefit of the LNG fuel chain isn’t offset by the service craft. Their greenhouse gas emissions are also lower than equivalent oil-fueled bunker barges. Additionally, by optimizing bunkering, they might reduce the need for LNG-fueled ships to detour or idle (which would waste fuel), indirectly cutting emissions further.

• Methane emissions during bunkering: A critical environmental aspect is controlling methane releases during the transfer process. Modern bunkering procedures aim for zero routine venting. The use of vapor return lines means vapors displaced from the receiving tank go back to the bunker vessel. Bunkering vessels often have onboard reliquefaction or compressors to re-liquefy or store that gas. If they can’t reliquefy, they may use the vapor in their engines (basically using it as fuel rather than venting). During cooldown of lines (pre-transfer), some small amounts of gas can be flared or vented if not captured, but new techniques minimize this (e.g., keeping lines cold between operations when feasible, or using inert gas to push out LNG instead of venting methane). As the industry matures, the expectation is that methane slip in bunkering operations remains extremely low. It’s important because a visible LNG vapor release could harm perception and waste fuel. So far, bunkering operations globally have had an excellent record with very few incidents of methane release beyond trace amounts.

• Safety record: LNG bunkering, when done according to procedures, has proven safe. Over the past years, thousands of LNG bunkering operations (truck and vessel) have occurred without major safety incidents. Bunkering vessels undergo regular emergency drills and are often required to have an exclusion zone around them during transfers (for example, other ship traffic may be kept a certain distance away, and non-essential personnel cleared from open decks nearby). Ports coordinate closely: often a bunkering permit for each operation is needed from the harbor master until it becomes routine. Many ports have published LNG bunkering safety frameworks.

• Incident response: In the unlikely event of an LNG leak or spill on water, LNG will rapidly evaporate forming a gas cloud that is initially very cold and heavier than air, then warms and rises. Bunkering vessels carry safety gear to manage such a scenario, such as water sprayers to dissipate the gas cloud and gas detectors to monitor dispersion. If a fire occurred (e.g., at the manifold), dry powder extinguishers specifically rated for LNG are used – water is generally used only to cool surfaces, not extinguish LNG fires (due to risk of spreading). The crew of bunkering vessels are drilled in immediate shutdown and disconnection to stop flow if any anomaly is detected. Quick-release mechanisms can seal hoses in milliseconds to isolate fuel flow.

• Environmental benefit vs. alternatives: It’s worth noting that by facilitating LNG fueling, bunkering vessels indirectly contribute to large reductions in harmful emissions (as detailed for ocean-going ships). If LNG bunkering vessels were not available, more LNG ships would have to rely on trucking (which might produce more road congestion and slight emissions from trucks) or onshore terminals (which might limit the flexibility and possibly cause ships to consume extra fuel waiting). So in the bigger picture, these vessels are an enabler for positive environmental outcomes in shipping.

• End of life and re-purposing: If some day LNG demand were to decline (post transition to hydrogen or etc.), bunkering vessels could potentially be repurposed as small LNG distribution ships for remote power generation or even converted to carry other cryogenic fuels. For example, studies have looked at whether LNG tanks could be used for liquid CO₂ or ammonia transport – not straightforward, but some parts of the investment could be repurposed rather than scrapped, meaning their environmental lifecycle might extend.

• Local community factors: Some ports initially faced public concern about LNG bunkering (fear of gas explosions, etc.). The presence of purpose-built bunkering vessels, operated by experienced crews, has helped alleviate such concerns, along with transparent safety practices. Ports often engage in community outreach about LNG safety. For instance, when the first bunkering vessel started in a port, demonstrations and info sessions were held to show how safely LNG is handled (flame tests, etc.). Over time, as operations continue incident-free, local acceptance grows and environmental groups often acknowledge the air quality improvements.

Regulatory and Operational Framework for Bunkering

Regulations around LNG bunkering vessels involve maritime safety as well as adherence to port and environmental rules:

• Vessel regulations: As seagoing ships carrying LNG, bunkering vessels must comply with the IMO’s International Gas Carrier (IGC) Code (since they carry LNG as cargo). They are essentially small LNG tankers, so they are built and certified under IGC Code which dictates design of LNG tankers. Additionally, when transferring LNG as fuel, they and the receiving ship fall under the purview of the IGF Code during that operation. Class societies give them special notations like “LNG Bunker Vessel” and verify that transfer arrangements meet both codes. They also must have approved LNG bunkering manuals and emergency manuals.

• Bunkering operation regulations: Most ports have developed LNG bunkering checklists and rules often derived from ISO guidelines or SGMF’s (Society for Gas as Marine Fuel) recommendations. Typically, before each bunkering, a checklist is completed jointly by the bunkering vessel Master (or officer in charge) and the receiving ship’s Master/Chief Engineer. This covers communications, emergency stop signals, ventilation on, no ignition sources, ESD systems tested, weather condition checks, etc. Once both parties and the port authority agree, permission to commence transfer is given. Regulations require constant monitoring; a common requirement is that a dedicated bunker supervisor on each vessel has no other duties during the operation. Port state control or harbor officials might occasionally observe operations for compliance.

• Licensing: Ports usually license specific companies to conduct LNG bunkering. For example, Singapore and Rotterdam have licensing regimes to ensure only qualified operators (with approved vessels and trained crew) do the job. These often involve compliance audits and proving of capabilities. Bunkering vessels also need to coordinate with traffic control – often bunkering is disallowed when lightning is present (due to risk of igniting vapors, albeit low), or when excessive waves could hamper the alongside position.

• International harmonization: Efforts have been made to harmonize procedures internationally so that an LNG bunkering vessel from one region could operate in another without confusion. The International Association of Ports and Harbors (IAPH) has promoted common guidelines. Mariners of bunkering vessels also have training requirements analogous to those on LNG carriers plus specific bunkering management training.

• Customs and tax: On economic regulatory side, LNG fuel is often subject to different import/export treatments than LNG as cargo. Some jurisdictions treat LNG bunker fuel as a duty-exempt export (like traditional bunker fuel). Bunkering vessels need to handle the customs paperwork accordingly when they load LNG at a terminal (it might be considered an export to international waters). This is typically handled by fuel suppliers but is a part of the operations that had to be sorted out, especially when moving fuel between countries in Europe or similar.

• Counting towards infrastructure targets: Government policies, such as the EU’s mandate for core ports to have LNG bunkering, have been satisfied in many cases by the introduction of an LNG bunkering vessel serving that port (as opposed to building a fixed LNG station). So regulators consider an LNGBV as fulfilling a port’s obligation to provide LNG fuel, given it effectively is part of the infrastructure network. This has spurred some public co-financing as mentioned.

• Emergency preparedness: Regulations usually require ports to have emergency response plans specifically for LNG bunkering incidents. Bunkering vessel operators coordinate with local fire departments and spill response teams, even though an LNG spill scenario is different (evaporative). Joint exercises are sometimes conducted, e.g., practicing a rescue or fire response during a simulated LNG leak. The regulatory oversight by both maritime authorities and local safety bodies ensures that bunkering vessels integrate into the port safety matrix.

Fleet and Key Examples

The global fleet of LNG bunkering vessels has expanded quickly over the last few years, mirroring the growth of LNG-fueled ships. Here are some figures and notable examples:

Fleet growth: In early 2019, there were only about 6 dedicated LNG bunkering vessels operating worldwide. By the start of 2022, this had grown to roughly 30–35 in operation, and it continued to rise through 2023 and 2024. As of late 2024, over 60 LNG bunkering vessels are in service globally. Industry sources project that this number will continue to climb, potentially reaching around 90–100 within a couple of years, given vessels on order. The growth rate (~20% increase per year recently) aligns with the increasing fuel volumes needing distribution. Additionally, beyond those in operation, dozens more are on order or under construction. For example, Japan is building more bunkering vessels for its ports (after its first, Kaguya, started in 2020), and new orders have been placed in China and South Korea to serve Asian demand.

Geographic deployment:

• Europe: The largest number of LNGBVs currently operate in Europe, which was an early adopter. Northwest Europe has several in the Amsterdam-Rotterdam-Antwerp (ARA) range and the Baltic. Examples: Kairos (7,500 m³, serving Baltic since 2019), Coral Methane (a small LNG carrier repurposed, sometimes bunkers in Scandinavia), Gas Agility and Gas Vitality (each 18,600 m³, operating out of Rotterdam and Marseille respectively under TotalEnergies to supply containers and cruise ships). Shell operates the Cardissa (6,500 m³) in Europe (though Shell has reportedly replaced Cardissa with a new vessel Gas Revolution for operations going forward, demonstrating fleet renewal). The UK’s first LNGBV, Britannia Seaways (chartered by Gasum), operates in Northern Europe as well. These vessels can roam; for instance, Kairos initially in the Baltic was later redeployed to serve elsewhere as needed.

• Asia: Singapore has two notable bunkering vessels: FueLNG Bellina (7,500 m³, joint venture of Shell and Keppel) and Pavilion Energy’s LNGBV (12,000 m³, delivered in 2023). Japan’s Kaguya (3,500 m³) operates in Tokyo Bay, fueling LNG ferries and soon larger vessels; it was built by Kawasaki Heavy and is run by a JV of MOL and public bodies. China launched its first bunkering vessel Hai Gang Wei Lai in 2022 (around 8,500 m³) serving the Yangtze delta region, and more are planned for major Chinese ports as China embraces LNG especially for large container ships they build for export clients. South Korea’s Daewoo Shipbuilding built a 7,500 m³ bunkering vessel SM Jeju LNG 2 which can bunker ships around Korean ports and also serve as small-scale LNG carrier domestically. Hong Kong will soon receive two 8,000 m³ bunker vessels to refuel LNG-fueled gas carriers calling at its new LNG import terminal and other ships.

• Middle East: Avenir Allegiance (7,500 m³) was delivered to serve the Middle East/Gulf region, the first of its kind there. Also, a larger 20,000 m³ bunkering vessel for Qatar is on order, aligning with Qatar’s huge new LNG-fueled fleet build-out.

• Americas: In North America, the approach has been different (barge solutions). The Q-LNG 4000 ATB bunkers cruise ships like Carnival’s LNG vessels in the Gulf of Mexico and also refueled an LNG-powered car carrier on its way through the Panama Canal. A second similar LNG bunkering barge, Clean Canaveral (also around 5,400 m³, an ATB), entered service in 2022 to support operations in Florida and the East Coast. On the U.S. West Coast, one LNG bunker barge is planned to supply ships in Southern California by 2025, as the first transpacific LNG container ships start calling there. Outside the U.S., Canada’s Vancouver has a small bunkering barge that fuels LNG ferries and will support ocean-going ships; in South America, Buenos Aires received some LNG bunkering by truck for a domestic ferry, but no dedicated vessel yet.

• Others: Several vessels under the Avenir LNG umbrella (a small-scale LNG distribution company) serve dual roles in places like the Mediterranean and Asia – e.g., Avenir Accolade (offering bunkering in Malaysia) and Avenir Aspire (in the Mediterranean). These vessels highlight how small-scale distribution and bunkering overlap.

Notable bunkering vessels:

• Engie Zeebrugge / Kairos: The world’s first LNG bunkering vessel, 5,100 m³, launched in 2017. It established operational procedures now standard. Initially fueling LNG-fueled car carriers in Zeebrugge for UECC and ferries for Brittany Ferries, it proved the concept. It was then renamed Kairos and moved to the Baltic Sea under charter to Linde/Gasum, fueling ships like ferries and tankers in Northern Europe.

• Gas Agility: Mentioned earlier with an image, its significance is being the largest and fueling the largest containerships. It carries enough LNG to fuel two ULCS on one load. Owned by Mitsui O.S.K. Lines and chartered to TotalEnergies, it operates mainly in Rotterdam but also travels to the French North Sea ports when needed. It and its sister Gas Vitality (stationed in the Mediterranean) represent the state-of-the-art, with membrane tanks and high transfer rates to minimize port time for clients.

• FueLNG Bellina: Asia’s first LNG bunkering vessel (aside from some Japanese small ones), delivered in 2021. It quickly ramped up operations in Singapore, fueling a variety of ships including tankers, a large FPSO on LNG trial, and even harbor craft. Singapore aims to use such vessels to supply 1-2 million tons of LNG bunker by 2030 annually, and Bellina was a key starting asset.

• Kaguya: A relatively small but symbolically important bunkering vessel, because it demonstrated Japan’s commitment. It has a semi-pressurized tank and serves both coastal ferries and occasional larger ships in Tokyo Bay. The learnings from Kaguya will feed into bigger vessels Japan is building to fuel its coming LNG cruise ships and cargo ships.

• Titan LNG’s FlexFueler barges: In the Amsterdam-Rotterdam-Antwerp area, a slightly different approach: small LNG bunker pontoon-barges (named FlexFueler 001 and 002) stationed in Amsterdam and Antwerp. These have around 1,400 m³ capacity and are positioned in port to provide flexible, quick fueling for inland and coastal vessels. While not seagoing, they highlight that even barge-based solutions are used in busy ports to complement the larger seagoing bunker ships.

Utilization examples: By 2024, many bunkering vessels were performing dozens of operations per year. SEA-LNG (industry coalition) reported that global LNG bunker volume reached around 4.7 million m³ in 2023 and was expected to hit ~7 million m³ in 2024, much of it delivered by bunker vessels. For instance, the port of Singapore alone delivered about 50,000 tons of LNG bunker in 2024 through its vessels, a number climbing as more ships call. Every successful refueling builds confidence and normalizes LNG as just another bunker fuel option.

Industry players: Key operators of LNG bunkering vessels include major fuel suppliers like Shell (operating in multiple regions), TotalEnergies, Gasum (in Nordics), Pavilion Energy (Singapore), and emerging specialized firms like Titan LNG (Europe) and Avenir LNG. These companies often work in partnership with shipowners: e.g., NYK Line not only runs cargo ships but also co-owns a bunkering vessel in Japan, and Mitsui OSK does similarly. This vertical involvement ensures alignment of interests (secure supply for their own LNG-fueled ships and a business opportunity in fueling others).

In summary, LNG bunkering vessels are the linchpin of the LNG fuel supply chain, effectively bringing the “fuel station” to the customer in a port or at sea. Their proliferation across key maritime hubs has underwritten the rapid expansion of LNG-fueled shipping, and their continued evolution (in size, efficiency, and geographic spread) will dictate how convenient and widespread LNG bunkering becomes. As LNG usage continues to grow, these vessels will be ever more common sights in ports, analogous to the traditional bunker barges of the oil era but delivering a cleaner product.

LNG-Fueled Port Support Vessels (Tugs and Service Craft)

Port support vessels – especially harbor tugboats – are critical for assisting ships in berthing, maneuvering within harbors, and performing various marine services. Traditionally, tugs have been powered by high-speed diesel engines that produce significant emissions close to shore. In pursuit of cleaner port operations and reduced local pollution, some ports and operators have begun deploying LNG-fueled tugs and related support craft. While fewer in number compared to ocean-going ships, these vessels showcase LNG’s viability even at smaller scales and in intense duty cycles. This section examines the technology of LNG-fueled tugs, their economic rationale (often tied to port policy and community benefits), environmental performance in port contexts, regulatory considerations for small craft, and current examples around the world.

Technology and Operation of LNG-Fueled Tugs

Harbor tugs present a different set of design challenges for LNG fueling than large ships due to their size constraints and operating profile:

• Engine and propulsion: Tugs require very high power in a compact vessel to achieve strong bollard pull (the pulling/holding force needed to maneuver large ships). Many modern tugs use two engines driving azimuth thrusters (360-degree steerable propellers) for maximum maneuverability. In LNG-fueled tugs, those engines can be dual-fuel or pure gas spark-ignition engines. For example, some LNG tugs use medium-speed dual-fuel engines (like Wärtsilä 34DF series) capable of running on LNG with diesel pilot, or spark-ignited high-speed gas engines (like Rolls-Royce mtu 4000 series gas engines). These engines are typically in the few-thousand kW range each. Importantly, because tugs often operate in short bursts of very high power (when pushing or pulling a ship) followed by idle or transit periods, having responsive engine performance on gas is crucial. Manufacturers have fine-tuned gas engine controls to handle rapid load changes, and some tug designs incorporate hybrid-electric systems to help. For instance, the new tug JMS Sunshine in Singapore is an LNG-hybrid: it runs primarily on LNG engines but also has a sizeable battery that can deliver peak power or allow low-speed electric maneuvering. This hybrid approach both improves response and further reduces emissions/noise when idling.

• Fuel storage on a small hull: Tugs are generally between 25 and 35 meters in length. Fitting an LNG tank in such a compact vessel is challenging as space is at a premium (tugs need to be short to fit in tight berths and have low draft). The typical solution has been to use Type C pressure vessels, often spherical or cylindrical tanks, placed in the aft part of the tug above the engine room. For example, one of the world’s first LNG tugs, Borgøy (built for operations in Norway in 2014), had a single approximately 80 m³ LNG tank located at the back of the vessel, housed in a visible steel enclosure. An 80 m³ tank might fuel the tug for a week or more of operations, depending on usage. Another tug, Sakigake in Japan, similarly had a 40 m³ cylindrical tank on deck. These tanks are small compared to those on large ships, but they are sufficient given tugs’ short range needs (they can refuel at their home port easily).

• Bunkering methods for tugs: Typically, LNG tugs refuel via truck-to-ship bunkering or shore facilities, since having an LNG bunker vessel for a single port’s tugs is not economical unless many other ships use it. For instance, the Port of Yokohama in Japan would bring LNG tank trucks to the pier to fill Sakigake. In Norway, small shoreside LNG stations exist where ferries or tugs can come alongside and bunker (these are fed by local LNG storage tanks). The fueling procedure for a tug is short – given the small volume, a couple of trucks might suffice. In some cases, tugs could potentially refuel from an LNG bunkering vessel if coordinated while that vessel is in port for other operations, but in practice trucks have been common for port crafts. Bunkering frequency depends on tank size and usage; an LNG tug might need to refuel every few days to weekly.

• Safety adaptations: The IGF Code and class rules cover tugs as well, but there are some special considerations. For example, the LNG tank on a tug is often quite exposed; it’s built with a robust double shell and often positioned such that collision risk is minimized (perhaps near the centerline and not at the extreme stern). Tugs often operate with crew onboard at all times, so accommodations and engine spaces are in close proximity – requiring good ventilation and gas detection throughout. The tug’s design must account for the high probability of impact and external fire (since they work near other ships and terminals). As such, their LNG systems are extremely rugged, often more so proportionally than in a big ship (because the relative risk of collision in a tight harbor is higher). Class rules for tug boats on gas ensure, for instance, that the LNG tank and pipes are shielded from potential contact with towing lines or other equipment.

• Operating profile: LNG-fueled tugs are meant to do the same jobs as any tug – towing, pushing, firefighting (some have FiFi systems), etc. On LNG, they can achieve the same power output. HaiSea Kermode, a new LNG dual-fuel tug in Canada, boasts over 100 tonnes bollard pull purely on gas – matching or exceeding conventional diesel tugs of similar size. Achieving instant power is critical in tug work; if gas engines have any lag, hybridization with batteries (as done in Singapore) is a clever solution that ensures no compromise in capability.

• Other port vessels: While tugs are the focus, it’s worth noting some ports also considered LNG for patrol boats or service vessels. One example is an Italian port authority vessel that was LNG-fueled, and there have been concepts for LNG-powered dredgers or workboats. These remain rare; the predominant port application so far is tugs.

Economic Considerations for Ports and Operators

The move to LNG in harbor craft is often driven by factors beyond pure fuel cost savings, as diesel for tugs is relatively cheap (marine diesel, and consumption is much lower than a large ship). Key economic considerations include:

• Environmental compliance and incentives: Many ports and local governments have introduced environmental requirements or incentives for harbor craft. For example, in California, new regulations require drastic emission reductions for harbor tugs and ferries, pushing toward hybrid-electric and could allow LNG as a compliance pathway (though California has leaned more to electrification for harbor craft due to zero-emission goals). In Europe, ports like Rotterdam and Hamburg have offered reduced port fees for tugs that have cleaner emissions or have provided grants via EU programs for demonstration projects. If an LNG tug helps a port meet its air quality targets or avoid fines for non-attainment (in air pollution controlled areas), that benefit might justify subsidizing the cost difference.

• Capital investment and partnerships: LNG tugs are more expensive than standard tugs, primarily due to the fuel system and perhaps additional complexity like a dual-fuel engine or hybrid system. The premium could be on the order of 10-30% more. Many ports have mitigated this via partnerships. For instance, the first LNG tugs in Norway (like Borgøy) were partially funded by the charterer (Statoil) and by Norway’s NOx Fund (an industry-environment fund that sponsors emission reduction projects). In Japan, Sakigake was supported by Japan’s Ministry of Environment as a demo case, offsetting costs. In Singapore, the development of JMS Sunshine (the LNG hybrid tug) was part of a grant by the Maritime and Port Authority under its Green Port initiatives. These financial assists are critical because tug operators (often private companies contracted by ports or shipping lines) might not see enough direct fuel savings to justify the investment otherwise, since LNG and diesel price differences for small volumes can be minor or even unfavorable after adding LNG logistics cost.

• Fuel cost and availability: Unlike large ships, tugs do not consume huge fuel volumes, so they don’t stand to save millions on fuel even if LNG is cheaper per unit. What matters more is price stability and availability. If a port has LNG available (e.g., if it’s already supplying big ships, then piggybacking for tugs is easier), then fueling tugs is straightforward. If not, trucking LNG to one tug might be costly on a per-unit basis. Some early LNG tugs in remote areas faced high LNG delivery costs, making operational costs higher than diesel initially. But as more usage emerges, those costs come down. A tug operator will compare the lifecycle costs: LNG may require additional training, perhaps slightly higher maintenance for the gas system (though engine maintenance could be lower thanks to cleaner combustion), and the logistic cost of getting LNG fuel delivered routinely. In some cases, ports lock in long-term LNG supply contracts for their tugs to ensure cost parity or better with diesel. For example, the port authority might negotiate with a nearby LNG terminal for a small allocation at a reasonable rate, or even use boil-off gas from an import terminal.

• Operating efficiency and image: Ports often operate tugs as part of their service offerings. If they can tout an LNG-fueled tug fleet, it enhances the port’s image as green and innovative, potentially attracting customers (especially cruise lines or certain cargo owners who care about full supply chain emissions). While hard to quantify, this reputational benefit is factored into decision-making in an era where sustainability reports and carbon footprint of logistics are increasingly scrutinized by investors and shippers.

• Lifecycle and future readiness: A tugboat can last 25-30 years. Investing in LNG now may protect the tug from future emissions restrictions that could otherwise require retrofits. For example, if down the line cities ban combustion engines in harbors or heavily tax fossil fuels, an LNG tug might be considered more acceptable or could possibly convert to bio-LNG or even hydrogen (there are theoretical concepts to convert gas engines to hydrogen blend). Some tug operators consider LNG a bridging step that, combined with hybrid tech, could later transition to 100% hydrogen or ammonia if engines are upgraded, essentially keeping the hull in service while changing fuel as technology allows.

In sum, the economics for LNG tugs are not typically about immediate fuel savings (as with big ships) but about strategic positioning for environmental compliance, port policy alignment, and benefiting from any grants/incentives – effectively lowering the real cost difference through external value capture.

Environmental and Community Impact

Harbor tugs operate right in port, often near city centers or coastal communities, so their emissions (or lack thereof) have a direct local impact:

• Local pollution reduction: One LNG-fueled tug can significantly reduce air pollutants in the port compared to a conventional tug. For example, one modern tug engine on diesel could emit NOₓ and particulate matter equivalent to hundreds of trucks due to its high power output and frequent ramp-ups. LNG eliminates almost all SOₓ and PM from tugs, which is a boon for nearby neighborhoods suffering from port emissions. NOₓ from LNG tugs is also greatly reduced, meaning less ground-level ozone and smog formation in port cities that are already emission hotspots. Ports such as Los Angeles/Long Beach have documented that harbor craft contribute a notable share of port NOₓ and PM emissions; converting some of those to LNG (or hybrid) can help meet clean air goals.

• GHG emissions: On a per vessel basis, a tug emits far less CO₂ annually than a large ship (because of fewer operating hours and lower total fuel burn), but it’s still a contributor. LNG tugs will have lower CO₂ emissions (maybe ~20% less) than diesel tugs. Notably, though, ports seeking carbon neutrality value every bit of reduction. Also, since tugs operate exclusively in a small area, their emissions are counted in local inventories (whereas a ship spends most time on the high seas). Thus, a port can directly reduce its scope 1 emissions by switching its service craft to LNG or other cleaner fuels. This is beneficial for port authorities under pressure to decarbonize operations.

• Noise and vibration: LNG engines can reduce noise pollution. For tug crews and people near the docks, LNG-fueled engines and hybrid drives can be quieter, especially if the tug can maneuver at low loads on batteries (like in Sunshine’s case). This is an often overlooked but positive effect – quieter tugs mean less disturbance to marine life (dolphins, etc., in port waters) and to residents near the water.

• Spill risk: Tugs occasionally have accidents (collisions, sinking) given their risky maneuvering tasks. A sunken tug with diesel on board can release bunker oil into the water, causing pollution in a confined harbor. An LNG tug carries fuel that if accidentally released would evaporate rather than pollute the water or shoreline. In that sense, LNG tugs reduce the risk of environmental damage from fuel spills in ports. That said, a large LNG leak in a harbor could pose immediate safety hazards (fire/explosion risk) until it dissipates, so it’s a trade-off – less chronic pollution risk, but need to manage acute flammability risk, which is done through design and procedures as discussed.

• Community and stakeholder acceptance: Communities around ports often campaign for cleaner port operations due to health concerns. Adopting LNG tugs can be part of port authority initiatives to show responsiveness to these concerns. For example, the Vancouver port’s decision to bring in LNG-hybrid tugs aligns with the city’s aspirations for cleaner air. In Japan, the operation of Sakigake in busy Tokyo Bay was in part to demonstrate to the public that even heavy-duty workboats can transition to cleaner fuels, supporting national emission reduction commitments. So LNG tugs serve as visible ambassadors of green port strategy. Crew members too often take pride in operating cleaner vessels, which aids morale and recruitment (seafaring is evolving to attract talent interested in sustainability).

• Challenges: methane slip in tugs: One might wonder if the methane slip issue is notable in tugs. Tugs typically use medium or high-speed gas engines which are often spark-ignited with very low methane slip (similar to land-based gas engines that meet strict emissions). Additionally, because tugs operate in highly scrutinized areas, designers ensure methane slip is minimal to avoid any question of local greenhouse gas release. It’s likely that, due to the focus on local air quality, slight differences in GHG weren’t a deciding factor for initial projects – the immediate removal of NOx/PM/SOx was the main driver. However, port authorities are generally aware that any technology adopted should align with long-term climate goals as well.

• Operational experience and feedback: Environmental feedback from early adopters is positive. For instance, after a period of operation of LNG tugs in Norway, it was reported that engine rooms were much cleaner (less soot deposits) and crew health incidents possibly improved due to better air on deck (no diesel fumes). These qualitative improvements reinforce continuing or expanding such initiatives.

Regulatory and Port Policy Aspects

• Safety regulations: Small LNG-fueled craft like tugs still fall under the IGF Code and class rules. Given their special nature, some flag administrations and class societies have issued supplemental guidelines for gas-fueled tugs. These include handling of bunkering in port (often requiring that a tug not perform other duties during refueling and that it refuels at a designated safe spot away from traffic). Port regulations may require that during bunkering of an LNG tug, other operations in the immediate vicinity (like loading of nearby ships) pause, though due to small quantity this is usually a brief interruption.

• Operational constraints: Ports generally incorporate LNG tugs into their emergency response planning. If an LNG tug has an incident (leak or fire), port fireboats and emergency teams are prepared specifically for LNG scenarios. Tugs themselves sometimes are equipped with firefighting capability (FiFi systems) and could assist in an LNG emergency of another vessel; ironically, an LNG-fueled FiFi tug might be the one responding to a fire on an LNG carrier or terminal, which is a scenario considered in drills (the tug’s own LNG systems are extremely well protected to be able to operate in a fire zone).

• Port bylaws and incentives: Some ports have created rules that any new tugs serving the port must be low-emission. For instance, the Port of London Authority signaled that future harbor craft should be hybrid or alternative fuel. In such cases, bidding for tug service contracts may even include extra points for LNG or hybrid capability. Port authorities that own tugs directly can simply decide their fleet renewal will be LNG or hybrid (like Singapore’s PSA Marine did). Incentives may include co-funding the cost difference for private tug operators if they agree to invest in LNG units – similar to truck replacement programs in ports, but here for marine craft.

• Training and crew qualification: Similar to larger ships, tug crew need training on LNG safety. Because a tug has a small crew (maybe 4 to 6 persons including captain and engineers), each person might take on multiple roles (the engineer might be the designated LNG officer, etc.). Ensuring such crew are trained to STCW gas-fueled standards is important. Port state control in theory could inspect harbor tugs for proper certification, though since tugs usually don’t voyage internationally, it’s more of a flag state and port authority oversight. So far, tug companies have taken this seriously – for example, before JMS Sunshine began operations in Singapore, its crew underwent extensive training including simulator runs and working with the LNG bunkering trucks that would fuel it.

• Interoperability: If an LNG tug from one port were to be chartered to another port, some regulatory differences might be encountered (like different refueling methods or slight differences in local laws). However, since these are so few and usually stay in one region, this hasn’t been a big issue yet. It may come up as more ports have one or two LNG tugs and sometimes share them for salvage or special operations.

Current examples and projects:

• Borgøy and Bokn (Norway): Delivered in 2014, these were the world’s first LNG-fueled tugs. Operated by Buksér og Berging, they primarily serve a Statoil (Equinor) terminal. They have Wärtsilä dual-fuel engines and about 65 tons bollard pull. These proved the concept in a cold environment and showed reliability in daily ops. They bunker from a small LNG terminal locally. Their success paved the way for others.

• Sakigake (Japan): Entered service in 2015 in Yokohama for NYK Line’s tug subsidiary. It has twin Yanmar dual-fuel engines and ~50 ton bollard pull. Sakigake performed well for 8 years; by 2023 it carried out its final LNG bunkering as it is slated to be converted to an ammonia-fueled tug as an experiment, which shows the forward-looking approach: use LNG now, aim for zero-carbon fuel next. Meanwhile, Japan built a second LNG tug Ishin (MOL’s tug, 2019) with similar specs, which has been bunkering with “carbon-neutral LNG” (LNG with offsets) and even did a bio-LNG trial in 2021.

• HAISEA Warrior & Kermode (Canada): In 2023–2024, five new tugs were built for the LNG Canada export terminal in Kitimat, BC. Three are battery-electric (for harbor moves) and two are LNG dual-fuel for escort duties (longer distance towing of LNG carriers through fjords). HaiSea Kermode and HaiSea Warrior are among the most powerful dual-fuel tugs built, with 100+ ton bollard pull, designed by Robert Allan Ltd and built by Sanmar in Turkey. They can sail on LNG all day and only use diesel as backup. These serve an LNG export terminal, which makes a strong statement of using the very product (LNG) they export to also fuel their support vessels. It helps LNG Canada project advertise reduced emissions in its operations.

• JMS Sunshine (Singapore): Delivered 2023, the first LNG-hybrid tug. Owned by Seatrium (formerly Sembcorp Marine) and operated by its subsidiary, it serves the Port of Singapore. Sunshine has two 16-cyl mtu gas engines plus batteries, giving it fine control and low emissions. It’s seen as a prototype for converting more of Sembcorp’s fleet of tugs to hybrid LNG in coming years. Sunshine was also interestingly bunkered by truck initially (Pavilion Energy did truck-to-ship fueling since Singapore’s bunkering vessel focuses on bigger ships). The port has expressed interest in all new harbor craft being low or zero emission by 2030, and Sunshine indicates LNG can play a role for the heavier end of harbor craft alongside electric solutions.

• Drydocks World LNG Tug (Dubai): The first LNG tug in the Middle East is under construction (as of 2024) by Drydocks World, in partnership with Wärtsilä, for Dubai port operations. It will also have some advanced design features. Its introduction will coincide with the UAE’s push for greener shipping in the region.

• Svitzer TRAnsform project: Maersk’s towage arm Svitzer had a project to develop an LNG tug (coined TRAnsform) about a decade ago, but Svitzer later diverted to testing battery and recently methanol tugs. Nevertheless, knowledge from that project influenced others. Svitzer did employ for a time the dual-fuel tug EcoTow in the UK (converted to run partly on LNG via a truck-fed system), but it was more a trial. Svitzer’s current focus is on methanol (another low-flashpoint fuel), showing that different companies choose different strategies.

Future outlook for port vessels: The uptake of LNG in tugs has been measured, as many ports are also eyeing fully electric or hydrogen for harbor craft to achieve zero emissions. LNG may not become the dominant harbor craft fuel globally, but in the near term it provides a practical way to slash emissions for the most powerful tugs that battery tech can’t yet fully support. We might expect LNG to power tugs especially in conjunction with LNG infrastructure (LNG terminals, or ports with lots of LNG-fueled large ships calling). In those contexts, synergy makes sense – the bunkering gear is there to fuel big ships, so fueling a small tug is minor extra effort. Meanwhile, completely green alternatives for tugs (like hydrogen fuel cells) are still experimental, giving LNG a window of opportunity over the next 5-10 years to cover the gap and cut emissions significantly. If those greener techs mature, some LNG tugs might eventually be retrofitted or phased out, but until then, they serve an important role in greening port operations.

Conclusion and Outlook

The rise of LNG as a marine fuel marks one of the most significant shifts in maritime propulsion in decades. Across ocean-going vessels, bunkering infrastructure, and port service craft, LNG has established a firm foothold, delivering tangible benefits in emissions reduction and compliance. This comprehensive review has highlighted that LNG is not a one-dimensional solution but rather a multifaceted pathway that involves new technologies, operational practices, investments, and collaborations across the maritime value chain.

Current status (2025): In summary, LNG-fueled vessels have transitioned from niche pioneers to a mainstream option:

• The global fleet of LNG-powered ships (excluding LNG carriers) now numbers in the many hundreds and spans virtually all commercial ship types. Adoption has been especially robust in sectors like container shipping, car carriers, and cruise lines for newbuilds, while retrofits of existing ships to LNG have been less common (due to complexity and cost). LNG bunkering infrastructure has rapidly expanded to match this fleet growth, with over 60 bunkering vessels in operation and nearly 200 ports offering some form of LNG bunkering service. LNG-fueled harbor tugs, while still few, demonstrate commitment to port-area emission reductions and will likely increase in ports where air quality is a pressing issue.

• Technologically, the industry has proven that LNG propulsion can meet the rigorous demands of deep-sea voyages and high-power maneuvers alike. Engine manufacturers have refined dual-fuel engines to improve efficiency and cut methane slip, and class societies along with the IMO have provided a robust regulatory framework that has thus far ensured safe operations. The combination of reliable technology and safety standards has given ship owners and financiers confidence to invest in LNG-capable tonnage without compromising performance or safety.

• Economically, while the case for LNG can vary with fuel prices, many shipping companies have determined that the long-term advantages (regulatory compliance, avoidance of sulfur and carbon surcharges, potential fuel savings, and market preferences) justify the initial costs. Notably, the integration of environmental externalities – like emission control area compliance costs and impending carbon pricing – has tipped the scales in favor of LNG in numerous analyses. The continuing orders for LNG-fueled ships even amid fluctuating gas prices indicate a strategic view that values fuel flexibility and compliance headroom. For ports and bunkering providers, LNG has opened a new market and revenue stream, aligning with broader energy transitions as many gas suppliers see marine LNG as a growth segment that complements their core LNG businesses.

• Environmentally, LNG has delivered on its promise of significantly cleaner exhaust in terms of air pollutants. Ports with frequent LNG vessels are observing reductions in sulfur and particulate emissions, contributing to healthier air for workers and residents. Greenhouse gas emissions are moderately reduced per voyage, and importantly, LNG vessels serve as a platform for further improvement – for instance, blending bio-LNG or synthetic methane when available can incrementally reduce their carbon footprint without new hardware. The concept of an “LNG pathway” to decarbonization is being actively pursued: in 2024, we saw the first instances of ocean-going ships bunkering a blend of bio-methane with LNG, and some LNG-fueled ships have been certified as carbon-neutral voyages when using such blends plus offsets. These are early steps, but they demonstrate that the infrastructure and ships being built now are not incompatible with the ultimate goal of zero emissions; rather, they can be part of that journey.

Challenges and considerations ahead: Despite the successes, LNG is not a panacea for all challenges, and the industry remains cognizant of certain challenges:

• Methane emissions control: Continued focus is needed to ensure methane slip from engines and any leakage in the supply chain is minimized. The industry is moving in the right direction, with engine innovations and better practices, but regulators may impose stricter requirements in the future. Proactive measures by shipowners and fuel suppliers to use best available tech will be critical to maintain LNG’s environmental credibility.

• Competition from other fuels: LNG is one of several contenders in the maritime fuel transition. Competing alternative fuels like methanol (derived from natural gas or potentially green methanol from renewable sources) and ammonia (a zero-carbon fuel, though still in development for use) are attracting interest. Some shipowners are hedging bets by ordering a mix of LNG-fueled and methanol-fueled newbuilds. The ultimate winners may vary by segment – for instance, some expect that by the 2030s, truly carbon-free fuels (ammonia, hydrogen) might start to take a share, especially if carbon regulations become very stringent. LNG enjoys a head start and large existing base, and its proponents aim to maintain momentum by emphasizing its immediate availability and pathway to renewables. However, LNG infrastructure could possibly be repurposed for other fuels (e.g., liquid hydrogen or ammonia terminals) in a post-2040 scenario if the world pivots. Thus, stakeholders are keeping an eye on ensuring infrastructure investments remain adaptable and that LNG-fueled ships possibly have “fuel readiness” options for conversion if needed.

• Economic volatility: The events of 2022 with skyrocketing gas prices served as a stress test. Some LNG-fueled vessels did temporarily switch to oil fuels when LNG became extremely expensive in certain regions. It underscored that fuel flexibility (the ability to burn diesel if needed) is an important feature of dual-fuel ships. Over the long term, with more diversified LNG supply and perhaps more stable pricing (especially as the market matures with bunkering contracts, etc.), the hope is to avoid such extremes. Ship operators will likely secure more long-term LNG fuel contracts to buffer spot market swings. In addition, growth of LNG as fuel could decouple it somewhat from general natural gas markets, as new production might be dedicated specifically to transport (some gas producers have considered projects for bio-LNG or synthetic LNG dedicated to shipping which would have different economics).

• Infrastructure gaps: While major ports are well-equipped, some secondary routes and ports still lack LNG bunkering. This could constrain certain trading patterns. For example, currently an LNG-fueled ship on a South America to Africa route might find limited refueling options. International cooperation and investments (perhaps via development banks or public-private partnerships) might be needed to broaden the geographic availability, especially in developing regions, to ensure LNG-fueled shipping can truly be global. The pace at which this happens could influence how attractive LNG is for tramp trades versus liner trades which can concentrate on known ports.

Outlook:

In the near-to-mid term (2025–2030), LNG is poised to continue growing as a marine fuel. The existing orderbook indicates a steady flow of new LNG vessels through at least 2027. By 2030, it’s conceivable that LNG-fueled ships could make up around 15-20% of the world’s newbuilding fleet in terms of tonnage (some forecasts suggest even higher, given nearly half of newbuilding tonnage in 2024 was ordered with alternative fuel capability and LNG had the lion’s share of that). As older ships are retired, the share of the operating fleet that is LNG-capable will correspondingly rise.

During this period, we will likely see:

• More integration of bio-LNG into the fuel mix. Perhaps small percentages initially (5-10%) becoming available at key bunkering ports, enabling shipping companies to claim further emissions reductions. Some dedicated bio-LNG production plants might be built in Europe or North America, tied to shipping demand.

• Technological refinements such as onboard carbon capture combined with LNG engines on some ships (a few pilot installations are underway to capture CO₂ from engine exhaust; if successful, an LNG-fueled ship with carbon capture could drastically cut net GHG emissions, albeit with added cost and complexity).

• Continued entry of larger LNG bunker vessels and possibly consolidation of bunkering operations for efficiency. We might also see standardized pricing indices for LNG bunker fuel emerge (similar to how VLSFO and MGO have benchmark prices), adding transparency and trust in the market.

• More port support adoption where appropriate: possibly a few more LNG tugs in big ports like Rotterdam or Busan as interim steps until full electrification is viable; and potentially LNG use in other port equipment (some ports consider LNG for rubber-tired gantry cranes or yard equipment, although electrification is more common there).

Beyond 2030, the trajectory will depend heavily on global decarbonization policy and technology breakthroughs. LNG could either plateau as zero-carbon fuels take over new investments, or it could co-evolve if bio/synthetic versions scale up and are accepted widely, thereby giving existing LNG assets a long lease on life. Given shipping assets last decades, even in a scenario where no new LNG ships are ordered after, say, 2040, we would still see LNG-fueled ships operating into the 2050s. Therefore, the investments made now in LNG are likely to have multi-decade impacts.

One promising outlook for LNG is that it may become a legacy clean fuel – similar to how some land transport has CNG or LNG trucks as a bridge until electrification, shipping’s LNG phase might stretch for a significant transitional period. If managed correctly, it will have achieved a substantial cut in pollutants and some GHG reduction during a critical time when the industry needed to move off high-sulfur residual fuel. And importantly, it buys time for the development of the next generation of fuels without slowing progress toward cleaner air and somewhat lower carbon footprint in the interim.

In conclusion, LNG-fueled vessels, bunkering systems, and port craft form an interconnected ecosystem that is reshaping maritime energy use. The technology is proven and deployment is accelerating. Economic and regulatory drivers remain generally favorable, although vigilance is needed to navigate market fluctuations and environmental concerns. Ports and shipping companies that have embraced LNG are reporting positive results and building expertise that could be transferable to future fuels as well. The experience gained with LNG – in handling cryogenics, managing dual-fuel systems, coordinating multi-party fuel supply – is invaluable groundwork for whatever comes next, be it hydrogen, ammonia, or something unforeseen. Therefore, LNG’s legacy in shipping will likely be both the immediate improvements it delivered and the foundation it laid for the industry’s ongoing journey toward sustainability.

The maritime sector tends to be conservative and risk-averse, but the rollout of LNG as a fuel has shown that with the right mix of caution and ambition, transformative change is possible. LNG-fueled vessels have moved from concept to reality, and now from novelty to normalcy on the world’s shipping lanes. As we look ahead, stakeholders will continue to monitor performance, share best practices, and innovate around LNG operations, all while keeping an eye on the horizon for the next evolution. In the meantime, the “LNG decade” underway is steering international shipping onto a cleaner course and stands as a tangible example of industry-wide adaptation in the face of global environmental challenges.

References

1. Clarksons Research (2025). Green Technology Tracker – Full Year 2024. Clarksons Research press release, 3 January 2025. (Summarizes 2024 alternative-fuel ship orders and fleet statistics, highlighting LNG as the dominant choice with 641 LNG-fueled ships in operation by end 2024 and a record number of new LNG ship orders.)

2. SEA-LNG Coalition (2025). “View from the Bridge” – 2024 Year in Review. SEA-LNG, January 2025. (Industry coalition report noting 33% annual growth in LNG-fueled vessels to 638 ships, expansion of LNG bunkering infrastructure to 198 ports and 60+ bunkering vessels, and progress in bio-LNG and e-methane developments.)

3. DNV – Alternative Fuels Insight (2025). Data summary as reported in Offshore Energy, 10 January 2025. (Provides updated figures on LNG-fueled fleet growth, including 169 LNG-fueled ships delivered in 2024, total 641 in service, and increase of LNG bunker vessels from 52 to 64 during 2024.)

4. Reuters (2024). “Steep discounts, new vessels spur demand for LNG to power ships.” Reuters News, 25 April 2024, by Jeslyn Lerh. (News article detailing LNG bunker price trends in 2024 with LNG fuel in Singapore at ~$100/ton cheaper than VLSFO, expected growth in LNG bunker volumes, and industry comments on emissions reductions ~20-30% with LNG.)

5. SEA-LNG (2019). Life Cycle GHG Emissions Study on the Use of LNG as Marine Fuel. SEA-LNG and SGMF report, April 2019. (Definitive study on emissions showing up to 21% reduction in GHG on a well-to-wake basis for LNG vs HFO, and significant reductions in local pollutants – virtually zero SOx, ~90% less NOx and PM – depending on engine technology.)

6. International Maritime Organization (2016). IMO IGF Code (International Code of Safety for Ships using Gases or other Low-Flashpoint Fuels). (Regulatory code outlining mandatory safety requirements for LNG-fueled vessels effective 2017, covering ship design, construction, equipment, operations, and training for gas-fueled shipping.)

7. Port of Rotterdam Authority (2020). Press release: “World’s largest LNG bunkering vessel arrives in Rotterdam – Gas Agility.” (Announcement of the deployment of Gas Agility, an 18,600 m³ LNG bunker vessel, including its specifications and role in servicing CMA CGM’s LNG container ships.)

8. Sanmar Shipyards (2023). “Sanmar delivers Canada’s first LNG-powered tug to HaiSea Marine.” News release, 11 Dec 2023. (Describes the delivery of the LNG dual-fuel tug HaiSea Kermode, its design (RAstar 4000-DF), 100+ ton bollard pull capability, dual-fuel engines meeting Tier III, and the environmental goals for its operation in British Columbia.)

9. Rolls-Royce Power Systems (2024). Press release: “First LNG tugboat with hybrid system goes into operation in Singapore – JMS Sunshine.” May 24, 2024. (Provides details on the JMS Sunshine tug, including its mtu gas engines, hybrid battery system, emissions performance (NOx and PM below detectable limits), and significance for the Port of Singapore.)

10. Lloyd’s Register & Port Authority Publications (2023). Various port and industry reports on alternative fuels infrastructure. (Collectively, these provide context on regulatory initiatives like the EU’s Alternative Fuels Infrastructure Regulation and port-level strategies to accommodate LNG bunkering as part of wider decarbonization efforts.)

11. Shell PLC (2025). Corporate report excerpt on LNG bunker deliveries. (Notes that Shell delivered a record volume of LNG as marine fuel in 2024, indicating growing consumption by the global fleet and Shell’s investment in bunkering vessels and supply chains.)

12. NYK Line (2023). News release: “LNG-fueled Tugboat Sakigake Conducts Final LNG Bunkering (to be converted to ammonia-fueled).” 26 July 2023. (Highlights the successful operation of Japan’s pioneering LNG tug Sakigake since 2015 and its planned conversion to ammonia fuel, illustrating the concept of using LNG as a bridge to future fuels.)

13. Bureau Veritas (2020). “LNG Bunkering – Technical and Operational Advisory.” (Industry technical guidance document summarizing best practices for LNG bunkering operations via truck, shore, and bunker vessel, as well as safety management and operator training requirements.)

14. Gasum & Titan LNG (2022). Company communications on LNG bunkering services. (Give insights into the operation of LNG bunker vessels like Kairos and FlexFueler barges, including their capacities, typical clients, and expansion of services to new ports.)

15. International Association of Ports and Harbors (IAPH) & SGMF (2021). LNG Bunkering Checklists and Guidelines. (Standardized operational checklists used globally to ensure safe and consistent LNG bunkering procedures between bunker vessels and receiving ships.)

16. Equinor (2019). Case study on LNG-fueled offshore vessels. (Discusses the rationale and results of using LNG-fueled shuttle tankers and platform supply vessels in Norwegian waters, including emission reductions and operational performance in practice.)

17. Carnival Corporation (2021). Sustainability Report – Marine Fuel Transition. (Details Carnival’s experience with LNG on cruise ships, the logistics of bunkering at various ports, and the passenger and environmental benefits observed.)

18. SEA-LNG (2024). “Focus on practicality drives LNG pathway growth in 2024.” SEA-LNG press release, 23 Jan 2025. (Emphasizes that LNG is providing immediate decarbonization benefits now, with plans for integrating bio-LNG and eventually renewable e-methane by 2026, reinforcing LNG’s role in a multi-fuel future and contributions toward 2050 targets.)

19. Maritime and Port Authority of Singapore (2022). Green Port Programme details. (Outlines incentives such as harbor craft grants and fee reductions that facilitated the development of LNG bunkering and LNG-fueled tugs in Singapore, exemplifying how policy supports adoption.)

20. LNG Industry Journal (2023). “Global LNG bunkering fleet update.” (Industry journal article summarizing the number of LNG bunkering vessels in operation and on order, trends in vessel size and design, and emerging regions entering the LNG bunkering market.)