The target operational carbon intensity for a given ship, year, and ship type.
Formula
$$ \text{CII}_\text{required} = a \cdot \text{Capacity}^{-c} \cdot (1 - Z) $$
Symbol legend
| Symbol | Meaning | Unit | Source |
|---|---|---|---|
| $\text{CII}_\text{required}$ | Required Carbon Intensity Indicator | g CO₂ / (cap·nm) | result |
| $a$ | Ship-type reference-line coefficient | - | MEPC.337(76) Table 1 |
| $c$ | Ship-type reference-line exponent | - | MEPC.337(76) Table 1 |
| $Capacity$ | DWT (most cargo ships) or GT (passenger / cruise / ro-pax / PCTC) | t or - | MEPC.337(76) |
| $Z$ | Annual reduction factor - 5 % (2023), 7 % (2024), 9 % (2025), 11 % (2026) | fraction | MEPC.338(76) |
Sources
- IMO MEPC.337(76) - reference lines.
- IMO MEPC.338(76) - annual reduction factors.
- IMO MEPC.336(76) - operational CII framework.
- ShipCalculators guide: What is CII?