As the global shipping industry accelerates its low-carbon transition, LNG-powered vessels have become a mainstream trend. One of the core systems supporting that trend is the FGSS (Fuel Gas Supply System).
Whether the project is a newbuilding or a retrofit, the FGSS plays a decisive role. So what exactly separates the two in technical and service terms? This article sets out a systematic comparison.
1. The role of the FGSS on board: more than a "gas supply system"
The FGSS is not merely a piece of gas supply equipment. It is an integrated system spanning safety, control and energy conversion, and its reliability directly determines the stability and safety of the whole gas-fuelled propulsion plant.
Its main functions are:
- Fuel conversion core: LNG is taken from cryogenic liquid storage and delivered to the main engine or generators in a stable condition after pressurisation, vaporisation and pressure regulation.
- Safety control hub: gas detection, ESD emergency shutdown, ventilation and explosion-protection systems are integrated to keep the entire process safe.
- Emission compliance: working together with the dual-fuel main engine, the system supports IMO emission requirements such as EEDI and CII.
- System integration platform: the FGSS works closely with the main engine and generator systems, the IAS control system, the GVU and BOG handling systems.
2. Newbuilding projects: system planning and standardised construction
In a newbuilding project the FGSS is brought into the overall vessel planning framework from the design stage, which brings clear advantages.
Design stage
- P&ID review and optimisation
- Optimisation of the 3D arrangement design
- Support for classification society submission
- HAZID / HAZOP risk assessment
Construction and commissioning stage
- Supply and coordination of key equipment
- On-site installation guidance
- Confirmation of control logic
- Commissioning of key equipment (cryogenic pumps, cryogenic valves, BOG compressors and similar)
Gas trial and delivery stage
- Drying and inerting, cooling down and LNG bunkering support
- Cold and hot commissioning
- Support during the gas trial
- Crew operational training
Characteristics of newbuilding projects: a high degree of design freedom, rational spatial arrangement, technical risk that can be controlled in advance, and smoother system integration.
3. Retrofit projects: a test of engineering experience and risk control
Compared with newbuildings, retrofit projects are more demanding. Converting a conventional oil-fuelled ship to LNG propulsion means adding to an existing structure.
Feasibility study
- Structural and strength assessment
- Stability calculations
- Analysis of space conversion options
Engineering design
- LNG fuel tank arrangement and structural reinforcement
- Re-planning of piping routes
- Control system upgrade and integration
Site implementation
- Matching the system to the existing main engine
- Compatibility testing
- Gas trial and certification
Characteristics of retrofit projects: restricted space, complex compatibility issues, tight schedules and many uncertain site factors — all of which test the experience and execution capability of the team.
Conclusion: integrated service capability is the key
As emission reduction pressure on shipping continues to grow and the number of LNG-powered vessels keeps rising, both the newbuilding and the retrofit FGSS markets are developing rapidly. In this environment the market needs service teams that can offer:
- Design and drawing review capability
- On-site installation and commissioning capability
- Risk assessment and problem-solving capability
- Training and long-term service support
Tecway has an experienced FGSS service team that has taken part in and successfully completed numerous newbuilding and retrofit projects, building up solid engineering practice along the way.
Drawing on a mature technical framework and proven site implementation capability, we provide whole-life technical support for FGSS projects, covering design optimisation, installation guidance, commissioning support, risk control and long-term operation and maintenance, so that projects are delivered safely, run stably and continue to create value.
Contact us
Pillar Liu | Technical Director
Email: pillar.liu@tecwayintl.com
About Tecway
Tecway International Limited was founded in Hong Kong in 1993 and is a leading technical consultant and quality agent for the global maritime industry. Over more than three decades it has built five core business areas: marine equipment, petrochemical storage and transport, diesel and gas engines, marine technical services and maritime consultancy, serving markets across China, Southeast Asia, the Middle East and Europe.
Tecway is a specialist team focused on green shipping and maritime consultancy services, addressing the core needs of shipping companies in their low-carbon transition with EU ETS and FuelEU compliance consulting, shipping green hydrogen project support, smart-ship dry-docking, export solutions for Chinese-made marine equipment and FGSS services.