Most Emission-Efficient Oil Tankers
Ships ranked by AER (Annual Efficiency Ratio) — grams of CO₂ emitted per tonne of deadweight carried one nautical mile (g CO₂/dwt·nm), the IMO carbon-intensity metric behind the CII rating — from official EU MRV emissions data for reporting year 2025. Lower is greener. Pick a segment and size class to see the greenest vessels first.
| # | Vessel | Size (DWT) | Built | Carbon intensity — AER (g CO₂/dwt·nm) | Grade |
|---|---|---|---|---|---|
| 652 |
SEACALM
IMO 9773753
|
112,119 | 2017 |
3.5
|
B |
| 651 |
AQUALOYALTY
IMO 9594664
|
115,594 | 2012 |
3.5
|
B |
| 653 |
NEELA
IMO 9593012
|
159,500 | 2015 |
3.5
|
B |
| 655 |
KAROLOS
IMO 9410208
|
162,418 | 2009 |
3.5
|
B |
| 654 |
CHRYSANTHEMUM
IMO 9417452
|
105,187 | 2009 |
3.5
|
B |
| 657 |
SEAFAITH
IMO 9843209
|
111,964 | 2020 |
3.5
|
B |
| 656 |
STEMNITSA
IMO 9693070
|
109,999 | 2013 |
3.5
|
B |
| 659 |
SFL LION
IMO 9664770
|
115,162 | 2012 |
3.5
|
B |
| 658 |
GREEN ATTITUDE
IMO 9808156
|
112,532 | 2018 |
3.5
|
B |
| 660 |
P. MONTEREY
IMO 9568172
|
105,525 | 2011 |
3.6
|
B |
| 665 |
HAFNIA GALATEA
IMO 9796975
|
109,990 | 2019 |
3.6
|
B |
| 668 |
BOCCADASSE
IMO 9829899
|
111,000 | 2018 |
3.6
|
B |
| 664 |
AL KHTAM
IMO 9823534
|
114,644 | 2021 |
3.6
|
B |
| 667 |
DIMITRIS P
IMO 9565950
|
157,740 | 2011 |
3.6
|
B |
| 663 |
VILAMOURA
IMO 9529293
|
158,621 | 2011 |
3.6
|
B |
| 662 |
PACIFIC SAPPHIRE
IMO 9893058
|
113,306 | 2021 |
3.6
|
B |
| 661 |
STI WINNIE
IMO 9696709
|
109,999 | 2015 |
3.6
|
B |
| 666 |
SEAVELVET
IMO 9843211
|
111,964 | 2020 |
3.6
|
B |
| 671 |
WHITE MOON
IMO 9588158
|
160,152 | 2012 |
3.6
|
C |
| 673 |
THORNBURY
IMO 9910533
|
112,066 | 2022 |
3.6
|
C |
| 670 |
KRITI HERO
IMO 9887308
|
158,005 | 2021 |
3.6
|
C |
| 669 |
BARBAROSA
IMO 9415399
|
164,746 | 2009 |
3.6
|
C |
| 672 |
SEARANGER
IMO 9759800
|
114,055 | 2017 |
3.6
|
C |
| 674 |
SEAVIGOUR
IMO 9774185
|
158,566 | 2016 |
3.6
|
C |
| 677 |
SAFEEN ELIZABETH
IMO 9524449
|
158,573 | 2011 |
3.6
|
C |
| 676 |
DREPANOS
IMO 9420643
|
107,467 | 2012 |
3.6
|
C |
| 675 |
MINERVA ELEFTHERIA
IMO 9787168
|
114,696 | 2018 |
3.6
|
C |
| 680 |
SEASPRITE
IMO 9711468
|
113,998 | 2015 |
3.6
|
C |
| 679 |
SEAMAJESTY
IMO 9601223
|
158,322 | 2012 |
3.6
|
C |
| 678 |
ELIAS TSAKOS
IMO 9724075
|
113,736 | 2016 |
3.6
|
C |
| 681 |
SEATRIBUTE
IMO 9857468
|
111,932 | 2020 |
3.6
|
C |
| 682 |
KLEON
IMO 9730945
|
109,999 | 2016 |
3.6
|
C |
| 684 |
SUEZ PROTOPIA
IMO 9380893
|
160,391 | 2008 |
3.6
|
C |
| 683 |
JAG LAKSHYA
IMO 9516117
|
157,641 | 2011 |
3.6
|
C |
| 686 |
DELTA SPIRIT
IMO 9419096
|
161,724 | 2010 |
3.6
|
C |
| 685 |
HAFNIA NESO
IMO 9800312
|
109,990 | 2019 |
3.6
|
C |
| 689 |
MARLIN HESTIA
IMO 9729233
|
74,260 | 2017 |
3.6
|
C |
| 688 |
KASOS
IMO 9800257
|
156,989 | 2018 |
3.6
|
C |
| 687 |
DECATHLON
IMO 9462926
|
158,475 | 2012 |
3.6
|
C |
| 693 |
DUBAI BEAUTY
IMO 9422548
|
115,382 | 2011 |
3.6
|
C |
| 696 |
SEA URCHIN
IMO 9886720
|
114,072 | 2019 |
3.6
|
C |
| 695 |
PALAMAS
IMO 9938042
|
115,286 | 2023 |
3.6
|
C |
| 694 |
PACIFIC DIAMOND
IMO 9893046
|
113,306 | 2021 |
3.6
|
C |
| 692 |
GREEN ADVENTURE
IMO 9927201
|
114,319 | 2022 |
3.6
|
C |
| 691 |
CAVALRY
IMO 9588146
|
160,095 | 2012 |
3.6
|
C |
| 690 |
PIS RINJANI
IMO 9792864
|
115,000 | 2019 |
3.6
|
C |
| 700 |
TOSKA
IMO 9996434
|
158,446 | 2025 |
3.6
|
C |
| 699 |
PRUDENT WARRIOR
IMO 9753545
|
149,995 | 2017 |
3.6
|
C |
| 698 |
NEW ABILITY
IMO 9361512
|
105,381 | 2008 |
3.6
|
C |
| 697 |
SEFERIS
IMO 9937024
|
113,839 | 2023 |
3.6
|
C |
Which engines power the greenest fleets?
The main engine is the single largest CO₂ source on board — typically well over 80% of a ship's emissions come from propulsion. We aggregated this ranking the other way around: every engine design is scored by the measured carbon intensity of the vessels carrying it, licensee-built units merged under their design brand. The verdict from the 2025 data — modern dual-fuel designs like MAN B&W's ME-GI and WinGD's X-DF families, together with EGR/SCR-abated and ultra-long-stroke G-type engines, consistently power the most emission-friendly ships in service.
AER (Annual Efficiency Ratio) = annual CO₂ emissions ÷ (deadweight × distance sailed), the IMO carbon-intensity metric used for CII ratings. It is built only from measured CO₂, distance and deadweight — not the self-reported cargo transport-work figure, which is unreliable. Implausible outliers (top 2% per segment) are excluded. Grade A–E reflects each vessel's rank within its segment. Source: EMSA THETIS-MRV.