An FLNG vessel is a floating natural gas processing plant. It performs a number of functions, including recovering natural gas from subsea reservoirs, processing the gas to remove impurities such as water, carbon dioxide, and other impurities, chilling the gas to liquefy it, and storing the liquefied natural gas in onboard tanks for delivery to specialized LNG tankers for distribution to markets worldwide. The FLNG unit will be located directly above the natural gas field, where it will transport gas from the field to the unit using risers. The unit will process the gas to produce natural gas, LPG, and natural gas condensate. Purified feed gas will be cleaned to eliminate impurities and then frozen to liquefy it before storage in the vessel's hull. Liquefied natural gas will be offloaded by the seagoing vessels, as well as other liquid by-products, for delivery to international markets. In contrast to traditional LNG terminals, where huge land-based plants are required, FLNG vessels eliminate the pipelines to take the gas onshore, constituting a cost-efficient way of developing remote or stranded gas fields.
FLNG vessels are used in various regions of the world where gigantic offshore natural gas reservoirs are found. Shell's Prelude FLNG, for instance, off the west coast of Western Australia, is probably the most renowned. With a 3.6 million tonnes per year (MTPA) production capacity of LNG, it is among the world's biggest and most complex FLNG operations to produce and liquefy natural gas in the field. The second significant deployment is Golar's own Hilli Episeyo, which was deployed offshore Campo Offshore in Cameroon. It has a capacity of 2.4 MTPA and is a great contributor to the monetization of the country's natural gas resources. It is known for its speed deployment and cost-effectiveness.
Responding to Malaysia, Petronas' PFLNG Satu has been a giant leap for FLNG technology, used to develop Kanowit field's gas. Having 1.2 MTPA capacity, the unit marks increasing adoption of floating LNG solutions in Southeast Asia. Similarly, Eni-operated Coral Sul FLNG off Mozambique is one of the world's largest FLNG units with 3.4 MTPA capacity. It will significantly boost Mozambique's LNG export capacity.
Along with traditional FLNG plants, hybrid ventures integrating FLNG technology with onshore processing are becoming the norm. LNG Canada, located in Kitimat, British Columbia, is a good example as it builds LNG export solutions based on potential synergies with FLNG technology. Thailand's Nao Siam FLNG, marketed by the PTT Exploration and Production Public Company, likewise aims to develop the country's LNG export capability while lessening reliance on land-based processing units. (1)
The leading players in the FLNG sector industry are major oil and gas players, shipbuilders, and engineering firms. Shell, Petronas, ExxonMobil, TotalEnergies, and Eni are a few companies that are leaders in establishing and operating FLNG projects. Shipbuilding giants Samsung Heavy Industries, Daewoo Shipbuilding & Marine Engineering, and Hyundai Heavy Industries have played key roles in constructing such advanced vessels. Additionally, engineering firms with experience in offshore energy solutions, such as TechnipFMC and KBR, assist in FLNG system integration and design and contribute to the future of the industry.
Of the fossil fuels, natural gas is amongst the cleanest-burning and offers a less harmful alternative to coal and oil. FLNG technology makes viable the efficient exploration of otherwise uneconomic offshore deposits of gas and thus is an essential element of the global energy transition. One of the principal environmental benefits of FLNG is that processing is done entirely at the gas field, thus avoiding the use of large pipeline networks, onshore compression facilities, and huge LNG processing facilities. This reduces the environmental impact by minimizing dredging, jetty building, and land-based infrastructure development, thus maintaining marine and coastal ecosystems. Secondly, FLNG units can be removed, refurbished, and relocated elsewhere once decommissioned, reducing long-term environmental impacts even further.
From an economic perspective, FLNG vessels are a cost-effective solution for the development of offshore gas fields that otherwise would be stranded due to the high cost of transporting gas to onshore facilities. This enables countries, particularly those in regions like East Africa, to monetize their natural gas resources economically. FLNG also has geopolitical advantages by bypassing the traditional territorial disputes that have frequently been generated when pipelines are built, such as in regions like Cyprus, Israel, and parts of Europe. Additionally, LNG is increasingly used as a direct fuel source without regasification, with economic and green options for road, rail, air, and sea transport.
Despite the many advantages of FLNG technology, there are a few challenges associated with it. The construction and installation of FLNG vessels consume enormous amounts of capital, often running into billions of dollars and capital-intensive processes. Additionally, the complexity of liquefaction and storage systems operating in harsh marine environments is critically risky from a technical perspective. Environmental concerns also play an important role, as governments and regulators are concerned about offshore gas production due to the potential to harm marine ecosystems (read further: EHS Risk Management: Calculating Offshore Risks).
Another significant issue is the small space on the vessels. The restricted deck area limits the capacity of feed gas that can be processed and stored, and FLNG units, therefore, suit gas streams with low content of inert gas and impurities. Approximately 50% of the deck area is typically occupied by pre-treatment of gases, and processability feasibility is determined in terms of impurity level in the feed gas stream. Impurities such as CO2, hydrogen sulphide, nitrogen, mercury, and acid gases dictate the scalability and efficiency of FLNG projects. These constraints necessitate careful planning and designing to optimize operations and enhance efficiency.
The future of FLNG vessels looks promising, driven by several factors. As nations transition to cleaner energy sources, they will play a vital role in meeting energy needs. Innovations in the technology, such as improved liquefaction efficiency and digital automation, will enhance their operational performance. Areas like Africa and Southeast Asia are increasingly considering FLNG solutions to unlock offshore gas reserves. Companies are exploring the potential for carbon capture and storage integration within FLNG vessels to align with global emission reduction goals. Golar LNG predicts that within the next five years, the number of FLNG units may nearly double. By 2030, it is estimated that there will be approximately 18 FLNG units globally, producing over 60 million tons of liquefied natural gas annually. Five FLNG units are operational worldwide, with an annual production of over 12 million tons.
Golar LNG Limited has signed an Engineering, Procurement, and Construction (EPC) agreement with CIMC Raffles for the construction of an MK II Floating LNG Production vessel, which will have a liquefaction capacity of 3.5 million tons of LNG per annum. The vessel is based on the conversion of the existing LNG carrier Fuji LNG, with a total project budget of $2.2 billion. It is scheduled for delivery in Q4 2027, making it the earliest available floating liquefaction capacity globally. Black & Veatch will provide its technology for the topside equipment and liquefaction process. With a delivered price of around USD 600 per ton of liquefaction capacity and an attractive Q4 2027 delivery, this FLNG order is positioned to offer prospective clients an attractive time-to-market to enable gas monetization while driving value for Golar. According to Golar LNG, the MK II design is an advancement of Golar's previous FLNG units, Hilli and Gimi, incorporating efficiency improvements and operational enhancements. Golar has already invested $300 million into the project, which is 63% complete. The agreement also includes an option for a second MK II FLNG unit to be delivered by 2028. (3)
See also our blog post about FPSO jobs.
What are the key benefits of FLNG vessels versus traditional onshore LNG plants?
FLNG vessels possess several fundamental advantages over traditional onshore LNG plants. Foremost among these is their ability to process natural gas in situ at the offshore field, eliminating the need for costly and long-distance pipeline infrastructure to transport gas onto land. Not only does this minimize project costs in total, but it also acts to mitigate environmental footprint through the prevention of large-scale onshore development. Besides, FLNG vessels provide operational flexibility because they can be transferred to other offshore blocks upon depletion of reserves. This allows for optimum resource use and reduces fixed onshore facilities' economic hazards. FLNG technology also enables countries with far-off-shore gas reserves to access international LNG markets, enhancing economic development and energy security.
What are the maintenance and operational challenges of FLNG vessels?
Although it has many advantages, FLNG vessels have many operational and maintenance problems. Due to the fact that space on board is very limited, all storage, liquefaction, and processing systems should be properly integrated with very advanced design and engineering solutions. Limited space also restricts the amount of feed gas to be processed at one time, and hence, FLNG units are more appropriate for gas streams with low inert gas and impurity levels. Harsh weather conditions offshore add additional challenges, including exposure to harsh weather and the need for highly skilled personnel to drive complex equipment. Maintenance activities may be more complex than in onshore facilities since accessing specialized repair shops in far-flung offshore locations is often logistically challenging. In addition, stringent environmental regulations require FLNG operators to adopt best practices in emissions reduction and marine ecosystem preservation by international standards.
FLNG vessels are an innovative breakthrough in the natural gas industry, enabling the economic and efficient development of offshore gas reserves. With their ability to unlock and monetize remote or stranded natural gas fields, those vessels play a key role in energy security and sustainability on a global scale. In a future where the world is moving towards lower-carbon fuels, FLNG vessels are an efficient and scalable solution that offers a bridge between fossil fuels and renewable energy resources. The continuous innovation of the technology, driven by industry innovators investing in efficiency improvements and environmental sustainability, will render them increasingly competitive. In addition, the geopolitical advantage, such as avoiding pipeline construction controversies, renders them an attractive option for most of the globe.
The FLNG market is expected to grow exponentially in the future, with improved adoption in emerging markets and technological progress driving enhanced efficiency. Governments and energy operators recognize the potential to provide economic returns while minimizing environmental disruption. As the industry develops further, ongoing innovation in automation, carbon capture, and emissions reduction will keep FLNG vessels a cornerstone of the world's energy industry for years to come. Despite the challenges of high capital outlays and complexity in operations, ongoing development and investment will ensure their sustained growth and relevance in an evolving energy environment.
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Natural gas - is a naturally occurring blend of gaseous hydrocarbons, primarily composed of methane (95%) and minor quantities of higher alkanes. It also contains trace amounts of carbon dioxide, nitrogen, hydrogen sulfide, and helium. Methane is a colourless and odourless gas and the second-largest contributor to global climate change after carbon dioxide. Since natural gas lacks a natural scent, odorants such as mercaptan, which has a distinctive rotten egg smell, are commonly added to facilitate leak detection and enhance safety (see also: .
Natural gas is classified as a fossil fuel, originating from the decomposition of organic material, mainly marine microorganisms, under high pressure and temperature in oxygen-deprived conditions over millions of years. The energy initially absorbed from sunlight by these organisms through photosynthesis is stored in the chemical bonds of methane and other hydrocarbons, making natural gas a valuable energy source. (4)
Sources:
(1) https://www.globenewswire.com/news-release/2025/02/05/3021262/0/en/Floating-Liquefied-Natural-Gas-FLNG-Market-Forecasted-to-Reach-USD-42-83-Billion-by-2029-Global-Industry-Growth-Driven-by-Technological-Advancements-and-Increased-Demand-for-Cleane.html
(2) https://www.oil-gasportal.com/floating-lng-flng-technical-challenges-and-future-trends/
(3) https://www.offshore-technology.com/news/golar-lng-cimc-epc-contract/
(4) https://www.eia.gov/energyexplained/natural-gas/