OPERATIONAL REALITIES VS. STATIC ASSUMPTIONS: RETHINKING FUEL EFFICIENCY METRICS FOR THE GFI TARGET

Abstract

This study examines the operational efficiency and greenhouse gas (GHG) emissions of offshore support vessels, comparing the validation mechanisms of Proxy A and the Energy Operational Index (EOI) within the context of the GHG Fuel Intensity Indicator (GFI). The results indicate that the EOI surpasses Proxy A in accuracy by incorporating dynamic operational data, such as engine loads in different modes, and correcting discrepancies in reported fuel consumption. In a case study of a vessel operating in tropical Brazilian waters, low engine loads during Dynamic Positioning mode (19%) revealed inefficiencies, while higher loads in Navigation mode (68.66%) demonstrated improved performance. The findings highlight the value of the EOI in ensuring reliable emissions data and its strategic role in supporting sustainable practices and realistic decarbonization goals for the maritime industry.