Theoretical Technical Efficiency Indexes
EIV and EEDI
Two different measures characterize the technical efficiency of ships. They are both measured in gCO₂/ton/nautical mile. They are theoretical measures: they really on applying formulas based on the characteristics of a ship, not on experimental measures.
- EIV: Efficiency Indicator Values
- EEDI: Energy Efficiency Design Index
Ships are invited to report a technical efficiency using one of these two indexes.
In the GreenFerries scope of passenger ferries:
- 255 ships have declared EIV values
- only 8 ships have reported using EEDI values
- 17 ships have not reported any of the two
Correlation between EIV and EcoScore
We tried looking for correlation between the theoretical technical efficiency and the EcoScore. The EcoScore is defined based on the reported annual average gCO₂/km/person. Considering the vast majority of ferries are reporting with the EIV value, we have chosen to ignore the EEDI values.
Here is a scatter plot of the EIV and this average gCO₂/km/person:
both axes are truncated to ignore outliers
Conclusion from observation: there does not seem to be any meaningful correlation between the two values.