Energy Efficiency Scores of Ro-Pax ferries in the Mediterranean

Abstract

The research explores the impact of energy efficiency regulations on the author's custom-built database of over 200 ferries commuting in the Mediterranean Sea region (Mijatovic 2023) in order to address their near future and urge design adjustments. For that purpose, an attained and a required Energy Efficiency Existing Ship Index (EEXI) are calculated for each ship. The findings indicated that 172 ferries, or 87% of the ships, met IMO requirements as shown in Fig.1.The IMO's reduction factors for EEXI reveals a notable pattern. In most ship categories, these factors closely resemble the reduction factors employed during the second phase of Energy Efficiency Design Index (EEDI) implementation. However, this congruence doesn't extend to Ro-Pax ferries, where a distinct trend emerges. Specifically, it's intriguing to observe that for newly constructed vessels, the reduction factor stands at 20% (IMO 2021), while for existing ferries, it's a mere 5% (IMO 2021). This significant discrepancy prompted the decision to conduct also an EEDI calculation for the existing fleet of ferries. The aim was to gain valuable insights into how effectively the current design and inherent attributes of these ships align with the requirements set for newly built counterparts. While the EEDI calculation has primarily been applied to new ship designs, it has often served as the primary metric for evaluating energy efficiency in both new and existing vessels throughout the years.