Generic capacity-normalised operational CO₂ intensity. Use whatever capacity denominator is appropriate for the fleet comparison - DWT, GT, TEU, lane-metre, reefer plug, etc.
Formula
$$ \text{cbDIST} = \frac{\sum_j F_j \cdot C_{f,j} \cdot 10^6}{\text{Capacity} \cdot \text{Distance}} $$
Symbol legend
| Symbol | Meaning | Unit | Source |
|---|---|---|---|
| $\text{cbDIST}$ | Capacity-normalised CO₂ intensity | g CO₂ / (cap·nm) | result |
| $F_j$ | Mass of fuel $j$ burned | t | IMO DCS / ship log |
| $C_{f,j}$ | CO₂ conversion factor for fuel $j$ | t CO₂ / t fuel | MEPC.364(79) |
| $Capacity$ | Commercial capacity basis (DWT, GT, TEU, lane-m, reefer plugs…) | varies | operator choice |
| $Distance$ | Distance sailed in the reporting period | nm | ship log |
| $10^6$ | Unit conversion tonnes → grams | - | constant |
When to use
Fleet dashboards where the IMO capacity basis doesn’t match commercial reality - e.g. comparing a containership by TEU and a ro-ro by lane-metre in a single view. Denominator units must match across ships in any one comparison.
Sources
- IMO MEPC.336(76) - operational CII framework.
- IMO MEPC.364(79) - Cf conversion factors.