MODERN LNG CARRIER TECHNOLOGY REPORT
From containment to propulsion, subcooling and reliquefication.
The LNG shipping industry: defined by innovation
Containment systems, propulsion methods, and reliquefication systems are driving the evolution of Liquefied Natural Gas (LNG) carriers. While these technical developments help address new needs for charterers and shipowners, they also pose new challenges.
Key Figures
The history of LNG carriers
The LNG carrier industry today
Technologies reshaping the LNG carrier industry
Various technical developments are changing the face of the LNG carrier industry:
- Containment systems: developers of these systems have reduced guaranteed boil-off rates (BOR) by half.
- Engines and propulsion systems: Some technical solutions for minimizing methane emissions include engine cylinder design and combustion optimization; selective catalytic reduction (SCR) with exhaust gas recirculation (EGR); methane oxidation catalysts with EGR; hybrid EGR and alternative fuel approaches; and other flexibility and efficiency gains, such as gas cylinder cut-off by Everllence.
- Reliquefication and subcooling systems: technical challenges have now been addressed, positioning reliquefication as a well-established onboard technology today.
The question of boil-off
When the boil-off rate (BOR) is below the vessel’s propulsion and power requirements, boil-off must be forced to produce fuel for the ship, or fuel oil must be used as an alternative. The issue is now less prevalent due to environmental and regulatory considerations. Further reductions in speed-fuel consumption and in the use of fuel oil are expected.
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Bureau Veritas Marine & Offshore
“We support stakeholders by identifying suitable technologies and helping them make informed decisions that prioritize both safety and efficiency.”
GTT systems are in constant development
Gaz Transport and Technigaz (GTT) systems are strongly preferred by owners ordering new LNG carriers. New GTT systems are being developed to address market demand for operational flexibility and cost efficiency.
The latest GTT LNG carrier designs include 3-tank arrangements that reduce BOR and capital expenditures by removing a cofferdam and some cargo handling equipment.
Managing BOR and BOG
A key concern when building a new carrier is ensuring a strong global architecture. For that, owners and yards need to balance the right containment and propulsion systems with the adequate supporting equipment.
When it comes to the research and decision-making required to define the global architecture, BOR stands out as the central factor in selecting cargo containment systems. All modern LNG carriers are designed to burn the boil-off gas (BOG) from their own cargo as fuel, to meet both their propulsion and auxiliary plant requirements. The balance between natural BOG and speed always has a strong impact on ships’ operational conditions and efficiency. In today’s market conditions, which require vessels to operate at maximum efficiency at a wide range of speeds, this creates many challenges that must be addressed in the design phase.
Today’s cargo containment systems
- Mark III Flex+: developed by GTT, it is offered by Korean and Chinese yards for their standard LNG carriers. It has standard prefabricated support panels of reinforced polyurethane foam and plywood, and two independent full barriers. It achieves lower BOR than the Mark III thanks to its thicker insulation.
- NO96 Super+: the latest evolution of NO96 systems already installed onboard LNG carriers. Currently offered by the Hanwha Ocean and Hudong-Zhongua shipyards, its technology is suitable for cryogenic temperatures, with a total insulation thickness of 530 mm.
- NEXT1: standard 174,000 m3 LNG carriers equipped with this system produce less than 60 tons of BOG per day. It combines elements of the Mark III and NO96 technologies, and its primary barrier is a corrugated sheet of stainless steel. The secondary barrier is a very thin invar sheet.
- Type B systems (Moss and prismatic): these achieve a lower insulation performance than modern ships equipped with membrane systems and 2-stroke engines. They are suitable for partial filing levels, ship-to-ship transfer offshore, and more, when addressing high sloshing pressures. They have been extensively used in applications like LNG carrier conversions. Structural assessment is, however, a crucial concern.
- Type C systems: typically used in small-scale LNG carriers, they are structurally independent from ship and made of single-shell steel alloys. Although they generate more BOG than larger tanks, they offer the possibility of using pressure build up for boil-off management.
Frequently Asked Questions
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What are the new applications for LNG as fuel?
Over the last several years, a new generation of large container ships using LNG as fuel has appeared. One example is the CMA CGM SEINE delivered by Hudong-Zhonguhua Shipbuilding (HAZSY) in April 2025.
Bureau Veritas is involved in the development of this new generation of ultra-large container vessels, which require specific adaptations to address challenges, notably those related to critical sloshing.
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How does Bureau Veritas help reduce emissions and optimize designs?
Bureau Veritas has always been at the heart of the LNG industry. From the assessment of the Beauvais (France’s first experimental LNG carrier) in 1962, Bureau Veritas has achieved many classification firsts.
Bureau Veritas collaborates with major industry stakeholders, including shipyards, shipowners, charterers, GTT and original equipment manufacturers (OEMs).
We have been involved in most of the established technologies that may contribute to finding a path for decarbonization, such as traditional energy saving devices (ESD) or air lubrication systems (ALS).
Bureau Veritas also provides strategic support to assess the impact of recent regulations, as well as intentions for new build considerations and inclusion.
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What factors play a role in design optimization for LNG carriers?
A range of key parameters and performance indicators may play a role in design optimization. These include:
- Hull optimization and propulsion assistance to minimize propulsion power and fuel consumption.
- Optimization of auxiliary power needs.
- Emissions reduction, including methane slip.
- Boil-off management optimization aiming for zero gas combustion unit (GCU) usage.
- Heel management optimization during ballast passages, including cooldown preparations.
- Port and cargo operations time optimization.
- Pre-and post-refit preparations
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What is the structure of LNG carriers today?
LNG shipping is an exercise in balancing critical factors. Of particular importance is the relationship between containment and propulsion.
In today’s market, size, propulsion systems and cargo management require additional built-in flexibility to fulfil speculative orders covered by relatively short-term charter contracts. The dominant technology is currently membrane systems, with GTT systems dominating LNG containment. Moreover, 2-stroke dual-fuel powered ships are the prevalent technology.
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Spearheading the energy transition | Bunkering for More Sustainable Future | Alternative Propulsion and Future Fuels | OptiCARBON™ | ||||
| Liquefied natural gas (LNG) is the transitional fuel of choice for marine stakeholders as the world moves towards net-zero emissions. Global demand for LNG has led to huge investments in production, infrastructure and the international development of distribution networks, fueling increased demand for LNG shipping. | The shipping industry is reducing emissions and making the transition to a lower-carbon future. One of the key steps being taken in that transition has been the development of LNG-fueled shipping, and the rise of large LNG Bunkering Vessels. | To meet ambitious targets set by the International Maritime Organization for limiting emissions and environmental impact, many ship owners are turning to low carbon fuels and alternative propulsion methods. We break down the state of the technology and how we can help shipowners implement it. | OptiCARBON™ is an integrated platform for shipowners and operators designed to optimize fuel and tax costs as well as emissions management. Backed by the expertise of Bureau Veritas, the platform is a resource for maritime stakeholders working to perfect their emissions strategies. | ||||
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