Comparison
Steam, DFDE and two-stroke propulsion compared
Fleet size, capacity and build era for the three propulsion families that mark LNG shipping's generational shift. For how each system actually works and why the industry moved on, see the propulsion explainer series.
Operating carrier fleet by propulsion type
Counts and figures are operating vessels only, from Global Energy Monitor's carrier tracker.
| Steam turbine | DFDE / TFDE | Two-stroke dual fuel | |
|---|---|---|---|
| Operating carriers | 223 | 199 | 338 |
| Average cargo capacity | 141,681 m³ | 165,022 m³ | 172,723 m³ |
| Average delivery year | 2004 | 2015 | 2022 |
| Earliest still operating | 1977 | 2006 | 2010 |
| Most recent delivery | 2018 | 2025 | 2026 |
Browse the full carrier directory, which lists propulsion for every vessel, or read the propulsion explainer series for how each system works.
Today's order book
Vessels under construction, pre-construction or proposed — the clearest sign the shift in the table above is still under way.
| Family | Vessels on order |
|---|---|
| Two-stroke dual fuel (ME-GI/X-DF) | 250 |
| Not reported | 130 |
| Dual-fuel diesel electric (DFDE/TFDE) | 18 |
Common questions
Each answer stands on its own.
- Which propulsion type is largest in the operating fleet?
- Two-stroke dual fuel, already: 338 operating carriers against 223 on steam turbines and 199 on dual-fuel diesel electric (DFDE/TFDE). It overtook both older families despite entering service only from 2010.
- Is steam turbine propulsion still being ordered?
- No. Of 398 vessels under construction, pre-construction or proposed, 0 use steam. New construction has used dual-fuel or two-stroke machinery for years; the propulsion-steam explainer covers why steam lasted as long as it did.
- How dominant is two-stroke dual fuel in today's order book?
- 250 of 398 vessels not yet operating — nearly every one with a propulsion type reported. It is now the default choice for new LNG carrier construction.
- Are steam-turbine ships older on average, or just less efficient?
- Both. Operating steam carriers average a delivery year of 2004, against 2022 for two-stroke dual fuel, and steam is also the least thermally efficient of the three at roughly 28 to 30 per cent, against about 50 per cent for a modern two-stroke engine — see the propulsion explainers for the efficiency figures in full.
- Is this every carrier in the tracker?
- No — figures here are operating vessels only, and only the three families with a clear generational story: steam, dual-fuel diesel electric and two-stroke dual fuel. Diesel and unclassified propulsion, a small share of the fleet, are excluded from this comparison but are shown on the main carrier directory.
For the engineering and the efficiency numbers behind each system, start with Steam turbines and why they endured, then DFDE and TFDE and ME-GI and X-DF.