The key difference between EEDI and EEXI is their application: EEDI applies to new ships while EEXI applies to existing ships.
Here's a more detailed breakdown:
Understanding EEDI and EEXI
Both the Energy Efficiency Design Index (EEDI) and the Energy Efficiency Existing Ship Index (EEXI) are measures established by the International Maritime Organization (IMO) to improve the energy efficiency of ships and reduce greenhouse gas emissions from the shipping industry. They both utilize the same calculation method to report ship energy efficiency, but target different vessel types.
Key Differences Between EEDI and EEXI
| Feature | EEDI (Energy Efficiency Design Index) | EEXI (Energy Efficiency Existing Ship Index) |
|---|---|---|
| Applicability | Newbuild Ships: Applies to new ships under construction. | Existing Ships: Applies to ships already in service. |
| Purpose | Sets a minimum energy efficiency level for new ship designs. | Sets a minimum energy efficiency level for existing ships. |
| Enforcement | Enforced at the design stage. | Requires technical modifications or operational limitations to comply. |
Examples
- A shipyard designing a new container ship must ensure it meets the EEDI requirements for its ship type and size before construction begins.
- A shipowner operating an older bulk carrier might need to install energy-saving devices or limit engine power to meet the EEXI requirements.
Practical Insights and Solutions
- For EEXI compliance, shipowners have several options:
- Engine Power Limitation (EPL): Reducing the maximum power output of the main engine.
- Energy-Saving Devices (ESDs): Installing technologies like propeller boss cap fins, pre-swirl stators, or air lubrication systems.
- Retrofitting: Replacing older, less efficient equipment with newer, more efficient models.
