Reefer correction
Container ships and reefer vessels carrying refrigerated containers consume extra fuel to keep cargo cold. IMO MEPC.355(78) recognises this is cargo-related rather than propulsion-related, and lets operators strip those emissions from the Attained CII calculation.
Formula
Reefer fuel (tonnes) = Cx × SFOC × Reefer-Hours / 1,000,000Reefer CO₂ (tonnes) = Reefer fuel × CFCorrected Attained CII = (Total CO₂ − Reefer CO₂) × 10⁶ / (Capacity × Distance NM)IMO default constants
The platform uses the MEPC.355(78) defaults:
| Constant | Value | Notes |
|---|---|---|
| Cx (default reefer power) | 2.75 kW | Per active reefer |
| SFOC (2-stroke engines) | 175 g/kWh | Default for container ships |
| SFOC (4-stroke engines) | 200 g/kWh | Alternate, configurable |
| CF (HFO) | 3.114 t CO₂ / t fuel | Default |
| CF (MGO/MDO) | 3.206 t CO₂ / t fuel | Alternative |
Inputs from the consumption log
The platform sums activeReefers × period across every report in the year to compute total reefer-hours. From there, fuel and CO₂ follow directly.
What you see
On the vessel detail page, two CII numbers are shown side by side:
- Database CII — what’s reported in the consumption logs (operator-supplied, may or may not include reefer correction depending on source)
- Corrected CII — the reefer-corrected figure computed by the platform
A link opens the full MEPC.355(78) PDF in an in-app slide-out for reference.
Implementation
src/lib/utils/ciiCalculator.ts — exports calculateReeferCorrection and calculateCIIWithReeferCorrection.
Reference
- IMO MEPC.355(78) — 2022 Interim Guidelines on correction factors and voyage adjustments for CII calculations
- IMO MEPC.364(79) — CO₂ emission factors (Cf) for HFO and MGO