Following up on last week’s newsletter on emission factors, this week we’ll focus on the practical application of those factors: calculating the GHG intensity of a ship under FuelEU Maritime. Using the example question posed on our LinkedIn quiz, we’ll provide a guide on how to correctly calculate the GHG intensity based on an example with a containership using heavy fuel oil (HFO).
What is GHG Intensity?
Under FuelEU Maritime, the GHG intensity is the ratio of total greenhouse gas emissions (in grams of CO2e) to the total energy consumed by the ship (in MJ). This value, expressed in g CO2e/MJ, is the metric used to determine compliance with FuelEU Maritime.
Example: Calculating GHG Intensity under FuelEU Maritime for a Containership in 2025
In this example, we will calculate the GHG intensity of a containership with 7,000 tonnes of annual HFO consumption (in scope) under FuelEU Maritime in 2025 (using AR4 Global Warming Potentials).
Step 1: Identify Calculation Parameters
Before diving into the calculation, we need to gather the relevant data:
Annual fuel consumption: 7,000 tonnes of HFO.
HFO’s Emission Factors:
The default well-to-tank (WtT) emission factor for HFO is 13.5 g CO2e/MJ.
Tank-to-wake (TtW) CO2: 3.114 g CO2/g fuel.
Tank-to-wake (TtW) CH4: 0.00005 g CH4/g fuel.
Tank-to-wake (TtW) N2O: 0.00018 g N2O/g fuel.
The values are according to Annex II of the regulation, as shown in Image 1.
Global Warming Potential (GWP):
GWP CO2: 1.
GWP CH4: 25.
GWP N2O: 298.
The values are according to AR4 as per FuelEU Maritime.
Step 2: Calculate Well-to-Wake (WtW) Emission Factor
Based on the above-identified parameters, the GHG intensity can be calculated. The first step is the calculation of the corresponding well-to-wake emission factor, for which it is mandatory to first determine the tank-to-wake emission factor for HFO based on AR4 GWPs:
From here, the well-to-wake emission factor can be calculated by adding the well-to-tank and the tank-to-wake part:
Note that the calculated tank-to-wake factor must be divided by the LCV to have the same unit.
Step 3: Calculate Energy Content of HFO
The next step is to calculate the total energy content of the 7,000 tonnes HFO consumed. The Lower Calorific Value (LCV) of HFO is 0.0405 MJ/g fuel (see Annex II image above). With that, the total energy used by the ship can be calculated to:
Step 4: Calculate Total Emissions
Next, we calculate the total greenhouse gas emissions using the well-to-wake (WtW) emission factor and the fuel consumption:
Step 5: Calculate GHG Intensity
Finally, we calculate the GHG intensity by dividing the total emissions by the total energy used onboard.
It can be noticed, that in the case of just one fuel type the GHG intensity equals the well-to-wake emission factor of the fuel type.
Note on AR4 vs. AR5 GWP Values
While the above calculation uses AR4 Global Warming Potentials (GWPs) as per the current regulatory text, it is important to note that the European Maritime Safety Agency (EMSA) has indicated that the regulation will shift to AR5 GWPs before January 2025. This means the GWP values for CH4 and N2O will change to 28 and 265 respectively, affecting the well-to-wake emission factor:
Conclusion
The GHG intensity of the containership consuming 7,000 tonnes of HFO annually under FuelEU Maritime in 2025 is 91.744 g CO2e/MJ based on AR4 values. The fuel consumption did not affect the resulting GHG intensity as the ship only consumed one fuel type.
Shipping companies should remain prepared for any adjustments in their emission factor calculations, as regulatory updates will incorporate AR5 GWPs.
Stay tuned for more insights on compliance calculations and strategies in our upcoming newsletters. If you have any questions or need further guidance on how to calculate GHG intensity or penalties under FuelEU, feel free to reach out!
Best regards,
The BetterSea Team
Contact Us: info@bettersea.tech
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