The application currently cannot consider emissions unrelated to a ship's engine. For example, the energy consumption of a ship using shore-power, electrical consumption on the ship (lightbulbs & cooking facilities for the crew for example).
See IMO's document MEPC.355(78) for the full list of considerations https://wwwcdn.imo.org/localresources/en/KnowledgeCentre/IndexofIMOResolutions/MEPCDocuments/MEPC.355(78).pdf