ecoFGSS-FLEX®
Today’s fuel decision should not become a fuel constraint in the future
Shipowners need a credible route to lower-emission propulsion without committing the vessel to an immature fuel pathway too early. ecoFGSS-FLEX® extends Babcock LGE’s established fuel-gas engineering into ammonia, providing a safe and practical route to ammonia fuel while retaining the flexibility to manage changing fuel availability and vessel requirements.
Download ecoFGSS-FLEX® brochureLNG -162°C
Ethylene -104°C
Ethane -89°C
CO₂ -55°C
LPG -48°C
Ammonia -33°C
Ammonia can change the vessel’s emissions pathway, but it also changes the risk
Ammonia offers a route to marine propulsion without carbon in the fuel molecule, but adopting it creates new engineering challenges around toxicity, containment, fuel conditioning, releases, interfaces and crew safety.
At the same time, owners are making vessel decisions before ammonia supply chains, bunkering infrastructure and fuel availability are fully mature in every trading region.
The customer problem is therefore not simply how to supply ammonia to an engine. It’s how to introduce a new fuel safely without making the vessel dependent on assumptions that may change over its operating life.
Build the ammonia capability on proven fuel-system engineering
ecoFGSS-FLEX® is based on Babcock LGE’s established ecoFGSS® LPG fuel-gas architecture and applies more than 50 years of Babcock LGE ammonia-handling experience.
The system has also been developed in close collaboration with leading ammonia dual-fuel engine manufacturers, allowing the fuel-supply architecture to be engineered around the requirements of the propulsion system as well as the properties of ammonia.
Proven fuel-system principles. Applied to a more demanding molecule.
Do not force today’s vessel decision to predict tomorrow’s fuel market
The original ecoFGSS-FLEX® concept was developed to give owners flexibility between LPG and ammonia fuel pathways, allowing the vessel to adopt ammonia when engine technology, fuel availability and supply infrastructure are established.
That flexibility matters because fuel strategy is now an investment decision as much as an engineering one. A vessel may operate for decades while the relative availability, cost and regulatory treatment of marine fuels continue to change.
The system should keep the fuel pathway open rather than turn uncertainty into stranded capability.
With ammonia, release management is part of the fuel system
Ammonia’s toxicity means that normal operating releases, purging and abnormal conditions cannot be treated as secondary details.
ecoFGSS-FLEX® is designed around the safety and environmental requirements of ammonia fuel use and integrates with wider vessel systems so that containment, isolation, conditioning and release management are considered together.
For the customer, the value is not simply compliance. It’s confidence that the fuel system has been engineered around the behaviour of ammonia from storage through to the engine interface.
Recover the ammonia instead of treating every release as waste
ecoVARS®, Babcock LGE’s patented vented ammonia recovery system can be integrated with ecoFGSS-FLEX® and the cargo handling system.
ecoVARS® can recover up to 90% of ammonia vapour that would normally be vented during engine purging operations and return it to the fuel storage tank. That converts a release-management requirement into economic, operational, safety, and environmental value.
Up to 90% recovery
Ammonia vapour from engine purging operations can be recovered and returned to the fuel storage tank under the stated ecoVARS® design basis.
Lower product loss
Recovered ammonia remains available as fuel rather than being treated only as a release stream.
Reduced release burden
Less ammonia requiring downstream treatment or discharge supports safer and cleaner operation.
Integrated architecture
Fuel supply, cargo handling and release recovery can be engineered as connected parts of the vessel gas system.
Contain it. Recover it. Return it to useful service.
Remove carbon from the fuel, then engineer the system that makes it useable
ecoFGSS-FLEX® enables the vessel to use ammonia safely and reliably, turning the fuel’s decarbonisation potential into a practical propulsion option.
Fuel supply cannot be separated from the vessel systems around it
Ammonia fuel supply interacts with storage, cargo handling, ventilation, release recovery, controls, safety systems and the engine.
Engineering these interfaces together reduces the risk that independently developed packages create conflicting requirements late in the vessel design.
Fewer unresolved interfaces
Fuel conditioning, safety, recovery and engine requirements can be considered within one system architecture.
One design philosophy
The same ammonia-handling principles are applied across cargo and fuel where Babcock LGE provides both scopes.
Engine collaboration
The fuel system is developed around the requirements of ammonia dual-fuel engine technology.
Clearer accountability
Integrated design reduces ambiguity at the interfaces that matter most during commissioning and operation.
For a new fuel, interface control is part of risk control
Optionality with engineering confidence
Decarbonisation pathway
Enable ammonia as a propulsion option as owners work towards lower lifecycle GHG (green house gas) intensity.
Fuel optionality
Avoid forcing a long-life vessel to depend on one fuel-market assumption made at the time of order.
Safety by design
Engineer containment, conditioning, releases and engine interfaces around the properties of ammonia.
Recovered product
With ecoVARS®, recover up to 90% of ammonia vapour that would normally be vented during engine purging operations.
For the shipowner, ecoFGSS-FLEX® is not simply an ammonia fuel skid. It’s a way to make a future-fuel decision without separating decarbonisation, safety and asset flexibility.
ecoFGSS-FLEX® builds on Babcock LGE’s established ecoFGSS® LPG fuel-gas system and decades of ammonia cargo-handling experience.
That matters because the safest route for new fuels is not to make every part of the system new at the same time. The architecture combines proven gas-system engineering with the additional requirements created by ammonia.
Innovation where ammonia demands it. Proven engineering where it does not.
Proof
2023
Lloyd’s Register AiP for ecoFGSS-FLEX®
2024
Lloyd’s Register AiP for ecoVARS®
2024
First commercial ecoFGSS-FLEX® contract
2025
Inaugural ammonia FGSS award announced
ecoFGSS-FLEX® received Lloyd’s Register (LR) Approval in Principle in 2023 for compliance with LR requirements for ships using gases or other low-flashpoint fuels, including ammonia.
Babcock LGE’s first commercial ecoFGSS-FLEX® contract was announced in July 2025 for four Medium Gas Carriers for Trafigura, being built at HD Hyundai Mipo.
Through-life support
A new fuel needs learning after the vessel leaves the shipyard
Early ammonia-fuelled vessels will generate valuable operational learning around fuel behaviour, maintenance, controls, crew interaction, and system performance.
Babcock LGE’s through-life model includes onboard engineering support, remote support and data analytics, training, system health-checks, dry-dock support, retrofit and upgrades.
That creates a route to carry learning from first operation into continued system development rather than treating commissioning as the end of the engineering relationship.
Engineer to engineer, through the transition and through the life of the vessel.
Make ammonia useable without making the vessel inflexible
ecoFGSS-FLEX® gives shipowners a practical route into ammonia propulsion by combining established fuel-system engineering, ammonia-handling experience, integrated safety and future-fuel flexibility.
The question is not simply whether the vessel can burn ammonia. It’s whether the vessel can adopt it safely, recover what would otherwise be lost, and retain the flexibility to respond as the fuel market develops.
Tell us the fuel strategy. We’ll bring the engineering.
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