All technology topics
Propulsion
LNG Carrier Propulsion Systems
Steam turbine, dual-fuel electric and two-stroke dual-fuel concepts, and how each interacts with cargo vapour.
Educational data
Schematic placeholder
Layer 01
Cargo tank vapour
Layer 02
Fuel gas supply system
Layer 03
Main engine (dual-fuel)
Layer 04
Shaft line or electrical distribution
Layer 05
Propeller
What it is
- Propulsion on LNG vessels is chosen together with the boil-off strategy, because vapour can be a fuel.
- Steam turbine, DFDE/TFDE, ME-GI and X-DF represent different points in that trade-off.
Where it is used
- All propelled LNG vessels; non-propelled barges rely on tugs instead.
Key design characteristics
- Steam plant: simple vapour acceptance, lower thermal efficiency.
- DFDE/TFDE: electrical distribution with flexible load sharing.
- ME-GI: high-pressure gas injection on a two-stroke engine.
- X-DF: low-pressure gas admission on a two-stroke engine.
Benefits
- Modern two-stroke dual-fuel plants generally improve fuel efficiency over steam designs.
- Electric configurations support redundancy and flexible machinery arrangements.
Operational considerations
- Each concept has different auxiliary systems, gas supply pressure and maintenance requirements.
- Efficiency and emissions behaviour are design and operating-profile dependent.
Related vessel segments
Related glossary terms
Technical information
- Status
- Educational overview — editorial review required
- Seeded educational summary awaiting editorial and technical review.
- Last reviewed
- 15 September 2026
- Source status
- Sources pending editorial review.
Technical parameters are indicative and may vary by vessel design, generation, shipyard, operator and intended service.