Fuel mass to CO2 mass conversion by carbon content of fuel
Clasification Society 2024 - Version 9.40
Statutory Documents - IMO Publications and Documents - Circulars - Marine Environment Protection Committee - MEPC/Circular.471 – Interim Guidelines for Voluntary Ship CO2 Emission Indexing for Use in Trials – (29 July 2005) - Annex - Interim Guidelines for Voluntary Ship CO2 Emission Indexing for Use in Trials - Appendix - Calculation of CO2 index based on operational data - Fuel mass to CO2 mass conversion by carbon content of fuel

Fuel mass to CO2 mass conversion by carbon content of fuel

 Although having many different physical characteristics, fuel oil mainly consists of hydrocarbons, e.g. C15H32. C has an atomic weight of 12.011, while Hydrogen (H) has 1. This yields carbon with a mass fraction limited to the range of 85 % to 87.5 %, where diesel oil is in the higher % range and heavy fuel oil in the lower % range. When combusted hydrocarbons react with oxygen (O), which have an atomic weight of 15.9994 then for each CO2 one C is needed. Using the atomic weights the ratio between CO2 and carbon is:

Multiplying with the mass fraction of carbon in the fuel we get the specific emission of CO2 (Ccarbon). Ccarbon for a fuel with 85% carbon content will be:

for heavy fuel oil with a carbon content of 85% by mass.

It is recommended to use direct carbon calculations.

If these data are not easily available in a first approach the following default values can be used for the carbon content and the factor CCarbon: µ.

Type of fuel ISO Specification Carbon content m/m CCarbon [g CO2 / t Fuel]
1 Diesel/Gasoil ISO 8217 Grades DMX through DMC 0.875footnote 3,206,000
2 Light Fuel Oil (LFO) ISO 8217 Grades RMA through RMD 0.86footnote 3,151,040
3 Heavy Fuel Oil (HFO) ISO 8217 Grades RME through RMK 0.85footnote 3,114,400
4 Liquid Petrol Gas (LPG)   0.81footnote 2,967,840
5 Natural Gas   0.80footnote 2,931,200
Parent topic: Appendix - Calculation of CO2 index based on operational data
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