MnrAq

42 Third IMO GHG Study 2014
Figure 28: Summary graph of annual fuel consumption (2012), broken down by ship type and
machinery component (main, auxiliary and boiler)
The detailed results for 2012, broken down by ship type and size category, are presented in Table 14. This
table displays the differences between ship types and sizes; for example, differences in installed power, speeds
(both design speed and operational speed) and as a result differences in fuel consumption. There are also
important differences between the amounts (number of ships) in each of the ship type and size categories.
When aggregated to a specific ship type, in sum, these explain the differences observed in Figure 27 and
Figure 28, and the differences presented in the last column (“Total CO 2 emissions”).
The table also displays information about the coverage of the fleet on AIS. The “IHSF” column under “Number
active” lists the number of ships reported as being in service in the IHSF database for that year. The “AIS”
column under “Number active” lists the number of ships that are observed in the AIS data at any point in time
during the year. In general, the coverage of the in-service fleet on AIS is consistently high (e.g. 95% and above)
for the larger ship sizes but less so for some smaller ship size categories (the smallest general cargo carriers in
particular). This could be indicative of a number of issues:
• low quality in certain size and type categories of the IHSF database for maintaining information on a
ship’s status (in-service indication);
• low-quality AIS coverage for the smallest ship types;
• low compliance with SOLAS, chapter V (that ships above a certain size must fit an AIS transponder).
The discussion of quality of coverage is extended in Section 1.4.
Further tables listing the same specifics for the earlier years of the analysis are included in Annex 2.