Well to Wake vs Tank to wake emissions for ICE

Hi, all can you share real time case study for life cycle emissions of Fossil fuel, for ships.
Presently EEXI, CII, is only considering the Tank to wake emissions, and there is no concern on Well to wake emissions. If suppose Tank to wake emissions are less that is if ICE is used efficiently & Workdone/co2 emissions for particular ship is good, but the well to tank emissions is very high, in same ship , how this can be demonstrated by real-time example case studies .

If any one can assist on this


Fuel EU maritime takes into consideration the well to wake emissions.

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Can you pls share any case studies of Situations where Well to tank emissions & tank to wake emissions, if we combine together well to tank + tank to wake the resulting outcome will change. Irrespective of efficacy of ship/vessel the results of full life cycle Emission of particular fuel should be considered and IMO is under consideration on this.

Hello @Sankpat12,

Here is a graph from ABS displaying the calculated lifecycle greenhouse gas (GHG) and carbon intensity of various fuels.

The well-to-tank portion is represented in blue, while the tank-to-wake portion is shown in orange.

For instance, ammonia has a carbon intensity of 1.6 gCO2eq/MJ for the tank-to-wake phase. Some may perceive this as an environmentally friendly option when solely considering the Energy Efficiency Existing Ship Index (EEXI). However, its intensity for the well-to-tank phase is 121 gCO2eq/MJ, which exceeds the entire well-to-wake emissions of Heavy Fuel Oil (HFO) at 78.7+14.1 = 92.8 gCO2eq/MJ, that demonstrates that it might not be the best solution and that only green ammonia could be competitive.


Thanks , & much appreciate on feedback. Can you pls share complete file of ABS on this topic. Thanks a lot.

The slide is from a topic presented at the Greener Shipping Summit 2022 in November titled “Where is IMO headed.” You can access the full presentation at this link.


Thank you very much Stela, for sharing the info. Appreciate.

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