Third IMO Greenhouse Gas Study 2014

106 Third IMO GHG Study 2014
This study used the following SO x EF baseline factors, based on HFO with 2.7% sulphur content. The EF baseline
factors for SO x are presented in Table 42. It should be noted that SO x and SO 2 are basically interchangeable
for marine-related engine emissions.
Table 42 – SO x baseline emissions factors
Eng speed/type Fuel 1 type ME EF baseline (kg/tonne fuel) Aux eng EF baseline (kg/tonne fuel) Reference
SSD
MSD
HSD
HFO
HFO
HFO
52.77
52.79
na
na
52.78
52.78
Mass balance 2
Mass balance 2
Mass balance 2
Otto LNG 0.02 0.02 Kunz & Gorse, 2013
GT HFO 52.79 na Mass balance 2
STM HFO 52.79 na Mass balance 2
Notes: 1 assumes HFO fuel with 2.7% sulphur content
2
assumes 97.54% of sulphur fraction is converted to SO x ; remainder is converted to PM SO 4
These baseline emissions factors are adjusted using FCF to account for the changing annual fuel sulphur
content world averages (2007–2012) or as required regionally within an ECA. The global sulphur content
of marine fuel oils was modelled according to IMO global sulphur fuel oil monitoring reports, as presented
in Table 43. For regional variations driven by regulation (ECAs), the fuel sulphur content is assumed to be
equivalent to the minimum regulatory requirement (see the description in Section 1.2 on how the shipping
activity is attributed to different global regions). Further regional variations of fuel sulphur content were not
taken into account owing to the complexity associated with points of purchase of fuel and where and when it
is actually burned. It is assumed that the world average is representative across the world fleet for each year.
Table 43 – Annual fuel oil sulphur worldwide averages
Fuel type 2007 2008 2009 2010 2011 2012
HFO/IFO 2.42 2.37 2.6 2.61 2.65 2.51
MDO/MGO 0.15 0.15 0.15 0.15 0.14 0.14
For further information on specific emissions factors, FCFs and references, see Annex 6.
PM baseline
The current literature contains a rather large variation of PM emissions factors, which vary significantly
between studies because of differences in methodology, sampling and analysis techniques. The United States
Environmental Protection Agency (EPA) and the California Air Resources Board (CARB) evaluated the available
PM test data and determined that along with direct PM there is secondary PM associated with the sulphur
in fuel (2.46% fuel sulphur fraction is converted to secondary PM while the remainder is emitted as SO x ,
as discussed previously). This study used the following PM EF baseline factors based on 2.7% sulphur content
HFO. The EF baseline factors for PM are presented in Table 44. It should be noted there is virtually no difference
between total PM and PM less than 10 microns or PM 10 for diesel-based fuels.
Table 44 – PM baseline emissions factors
Eng speed/type Fuel 1 type ME EF baseline (kg/tonne fuel) Aux eng EF baseline (kg/tonne fuel) Reference
SSD
MSD
HSD
HFO
HFO
HFO
7.28
6.65
na
na
6.34
6.34
EPA, 2007
EPA, 2007
EPA, 2007
Otto LNG 0.18 0.18 Kristensen, 2012
GT HFO 0.20 na IVL, 2004
STM HFO 3.05 na IVL, 2004
Notes: 1 assumes HFO fuel with 2.7% sulphur content