Answer
The Environmental Ship Index (ESI) is a voluntary global rating system developed under the World Ports Climate Initiative (WPCI) and managed by the International Association of Ports and Harbors (IAPH). It identifies sea-going vessels that perform better in reducing air emissions than required by current IMO MARPOL Annex VI regulations.
How the ESI Score Works
- Scoring Range: Scores range from 0 to 100, where 0 represents a ship meeting the baseline statutory compliance limit, and 100 indicates near-zero emissions performance.
- Data Verification: Shipowners enter verified engine certificates, fuel delivery notes (BDNs), logbook records, and shore-power readiness data into the central ESI database. Scores are updated semi-annually.
Key Evaluation Parameters
- NOx Emissions: Evaluates main and auxiliary engine nitrogen oxide emissions relative to IMO Tier I, II, or III emission standards.
- SOx Emissions: Assesses fuel sulfur content utilized in territorial waters and ports compared to MARPOL Annex VI caps (0.10% in ECAs / 0.5 % globally), or the use of approved exhaust gas cleaning systems (scrubbers).
- CO2 / Greenhouse Gas Performance: Evaluates fuel efficiency improvements using historical fuel consumption reporting, EEDI/EEXI data, or speed-reduction measures.
- Onshore Power Supply (OPS): Grants bonus points if the vessel is equipped for High Voltage Shore Connection (HVSC) / cold ironing to eliminate auxiliary engine emissions while berthed.
Commercial & Operational Benefits
- Port Dues Discounts: Over 50 major global ports (e.g., Rotterdam, Singapore, Hamburg, Antwerp) offer financial incentives, such as 5% to 20% reductions on port call dues, for vessels maintaining high ESI scores.
- Commercial Advantage: A high ESI score improves charterability by demonstrating environmental compliance to charterers prioritizing decarbonization goals.