OSVs sit outside the IMO CII regime (no transport-work denominator). Operators benchmark on daily or bollard-pull-hour intensity.
Formula
$$ \text{CO}_2^\text{year} = \sum_j F_j \cdot C_{f,j}, \quad \text{Intensity} = \frac{\text{CO}_2^\text{year}}{d_\text{op}} $$Symbol legend
| Symbol | Meaning | Unit | Source |
|---|---|---|---|
| $F_j$ | Mass of fuel $j$ | t | bunker log |
| $C_{f,j}$ | CO₂ factor | t CO₂ / t fuel | MEPC.364(79) |
| $d_\text{op}$ | On-hire operational days | d | voyage log |
Sources
- Oil & Gas UK - EPOD.
- DNV - Offshore Vessel Environmental Performance.