Sustainability features require a schema version of 469 or higher. The configuration flags CFGSustainability and CFGEnableCO2Pricing need to be enabled, along with the specific regulation configuration flags CFGEnableFuelEU and CFGEnableUkEts.
Introduction
The Carbon Calculator in IMOS currently supports three regulations: FuelEU, EU ETS, and UK ETS. Each regulation calculates emissions using fuel and fuel factor data configured in Data Center → Fuel/Lube Types, and their requirements overlap significantly.
Some factor fields are shared across all three regulations, while others are specific to FuelEU or to EU ETS/UK ETS. This article walks through how to set up fuels and fuel factors so that all three regulations calculate correctly.
Capturing the Emission Factors
Before relying on Carbon Calculator output, the factor field values for each fuel type in Data Center → Fuel/Lube Types should be verified by each company. Throughout this article we will specify which emission factors belong to each regulation.
Veson Nautical does not impose carbon factors, since companies may name and blend fuels differently. It is the company’s responsibility to confirm that the values entered match the fuels actually being consumed.
Below are the default values defined by the EU in the published REGULATION (EU) 2023/1805 OF THE EUROPEAN PARLIAMENT AND OF THE COUNCIL, along with Veson Nautical’s interpretation of the equations used to calculate the WtT CO2eq, TtW CO2eq (AR4), and TtW CO2eq (AR5) using both the Fourth & Fifth Assessment Reports of the Intergovernmental Panel on Climate Change (IPCC).
|
Fuel Type |
CO2 Factor |
TtW CH4 |
TtW N2O |
LCV |
WtT CO2eq |
TtW CO2eq (AR4) |
TtW CO2eq (AR5) |
|---|---|---|---|---|---|---|---|
|
HFO |
3.114 |
.00005 |
.00018 |
.0405 |
13.5 |
3.1689 |
3.1631 |
|
LFO |
3.151 |
.00005 |
.00018 |
.041 |
13.2 |
3.2059 |
3.2001 |
|
MDO/MGO |
3.206 |
.00005 |
.00018 |
.0427 |
14.4 |
3.2609 |
3.2551 |
|
LNG |
2.750 |
0 |
.00011 |
.0491 |
18.5 |
2.7828 |
2.7792 |
Setup of Carbon-Specific Factor Fields
The following three factor fields are shared across all three regulations — FuelEU, EU ETS, and UK ETS — and must be populated in Data Center → Fuel/Lube Types for each fuel type:
-
CO2 Factor – the Tank-to-Wake CO2 emissions factor, expressed as tons of CO2 emitted per ton of fuel consumed. If a fuel's CO2 Factor is left blank or is ≤ 1.0000, dependent CO2 fields elsewhere in IMOS will not calculate.
-
TtW CH4 Factor – the Tank-to-Wake methane (CH4) emission factor for the fuel.
-
TtW N2O Factor – the Tank-to-Wake nitrous oxide (N2O) emission factor for the fuel.
FuelEU Specific Fields Setup
In addition to the shared factor fields above, FuelEU calculations rely on the following fields:
-
LCV – Lower Calorific Value, expressed in MJ/g, representing the energy content of the fuel.
-
WtT CO2eq – Well-to-Tank CO2 equivalent emissions, i.e., the upstream emissions from producing and transporting the fuel before it reaches the vessel.
-
TtW CO2eq (AR4) – Tank-to-Wake CO2 equivalent emissions, calculated using Global Warming Potential (GWP) values from the IPCC's Fourth Assessment Report (AR4). This field drives the FuelEU carbon calculation.
-
LNG Equivalent – This check box indicates an LNG fuel type. Selecting this check box applies the Cslip value based on the engine type defined under the vessel only. No other LNG behaviors are applied when selecting this check box. Please review the FuelEU Maritime Calculator page to complete this setup.
About AR4
AR4 refers to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, published in 2007. It defines the 100-year Global Warming Potential (GWP) values used to convert non-CO2 greenhouse gases into CO2-equivalent terms: CH4 = 25 and N2O = 298 (CO2 = 1).
Calculation:
TtW CO2eq (AR4) = CO2 Factor + (TtW CH4 Factor × 25) + (TtW N2O Factor × 298)
The FuelEU Maritime Regulation (EU) 2023/1805 currently applies these AR4-based GWP values, consistent with the values carried over from the Renewable Energy Directive (EU) 2018/2001 (RED II).
Source: IPCC Fourth Assessment Report, Working Group I (2007); REGULATION (EU) 2023/1805 OF THE EUROPEAN PARLIAMENT AND OF THE COUNCIL.
EU ETS and UK ETS Specific Setup
EU ETS and UK ETS calculations rely on one additional field in addition to the three factor fields:
-
TtW CO2eq (AR5) – Tank-to-Wake CO2 equivalent emissions, calculated using GWP values from the IPCC's Fifth Assessment Report (AR5). This field drives EU ETS and UK ETS carbon calculations.
If the AR5 field is left blank, EU ETS and UK ETS calculations will fall back to the TtW CO2eq (AR4) field.
About AR5
AR5 refers to the Fifth Assessment Report of the IPCC, published in 2013. It updated the 100-year GWP values to: CH4 = 28 and N2O = 265 (CO2 = 1).
Calculation
TtW CO2eq (AR5) = CO2 Factor + (TtW CH4 Factor × 28) + (TtW N2O Factor × 265)
These AR5-based values are the basis for the EU MRV Regulation (EU) 2015/757, as amended by Regulation (EU) 2023/957, which underlies both the EU ETS and UK ETS treatment of CH4 and N2O emissions in shipping.
Source: IPCC Fifth Assessment Report, Working Group I (2013); Regulation (EU) 2015/757 on the monitoring, reporting and verification of CO2 emissions from maritime transport, as amended by Regulation (EU) 2023/957.
Optional Setup Options
For more on optional fuel setups related to the Carbon Calculator, see the following articles: