Cradle-to-gate embodied CO₂ for a new ship’s hull and machinery.
Formula
$$ \text{Embodied CO}_2 = \sum_i m_i \cdot \text{EF}_i $$
Symbol legend
| Symbol | Meaning | Unit | Source |
|---|---|---|---|
| $m_i$ | Mass of material $i$ | t | structural weight report |
| $\text{EF}_i$ | Emission factor for material $i$ | t CO₂ / t | WorldSteel / IAI / EPD databases |
Typical emission factors:
| $Material$ | EF (t CO₂ / t) |
|---|---|
| $Steel - BF/BOF world average$ | 2.0 |
| $Steel - EAF (scrap-based)$ | 0.4–0.8 |
| $Steel - H-DRI + EAF (green)$ | 0.1–0.3 |
| $Aluminium - world average$ | 10 |
| $Aluminium - hydro-smelter$ | 3 |
| $Copper$ | 4 |
| $Machinery assembly$ | 5 |
| $Paint / anti-fouling$ | 3.5 |
A 20,000 t steel bulker built from BF/BOF steel embodies ~40,000 t CO₂ - roughly 2 years of operational emissions at typical utilisation.
Sources
- WorldSteel - Life Cycle Assessment methodology.
- IMO MEPC - 4th IMO GHG Study.
- ISO 14040 - Life cycle assessment principles.