GHG balance of ship recycling - tow-fuel, dismantling energy, and the scrap-steel credit that displaces virgin blast-furnace steel.
Formula
$$ \text{Net} = \text{CO}2^\text{tow} + \text{CO}2^\text{yard} - m\text{scrap} \cdot (\text{EF}\text{BF-BOF} - \text{EF}_\text{EAF}) $$
Symbol legend
| Symbol | Meaning | Unit | Source |
|---|---|---|---|
| $\text{CO}_2^\text{tow}$ | CO₂ from final tow | t | tow fuel × Cf |
| $\text{CO}_2^\text{yard}$ | Yard operations CO₂ | t | LDT × dismantling factor |
| $m_\text{scrap}$ | Recovered scrap steel | t | LDT × steel fraction × recovery |
| $\text{EF}_\text{BF-BOF}$ | Virgin steel emission factor (BF/BOF) | t CO₂ / t | ~2.0, WorldSteel |
| $\text{EF}_\text{EAF}$ | Scrap-based EAF emission factor | t CO₂ / t | ~0.7, WorldSteel |
Net is typically negative (CO₂ avoided) because the scrap credit dominates. A 20,000 LDT bulker yields ~16,000 t of scrap → ~20,000 t CO₂ credit, vastly exceeding the ~1,500 t from tow + dismantling.
Sources
- IMO - Hong Kong International Convention on Ship Recycling.
- EU Ship Recycling Regulation 1257/2013.
- WorldSteel - scrap and recycling data.