Environmental Ship Index (ESI)
The Environmental Ship Index scores a ship's NOx and SOx performance above regulatory minima and is used by ports worldwide as the basis for dues discounts.
The Environmental Ship Index (ESI) scores a ship on air emissions performance beyond the regulatory minimum, and is administered by the Green Award Foundation. It is recognised by the IMO as a basis for port incentive schemes, and participating ports and other incentive providers use the score to set discounts on dues.
The index is formula-based on nitrogen oxide and sulphur oxide performance, which distinguishes it from a greenhouse-gas design benchmark such as the RightShip GHG Rating . Conflating the two is a common commercial error: an owner chasing a port-dues rebate is working on the wrong instrument if it is optimising a carbon-intensity letter, because no port authority prices dues off that letter.
The full article will cover the scoring formula and its NOx and SOx components, the registration and verification route, the participating incentive providers, the Port of Rotterdam discount structure, and the relationship between the ESI, Green Award certification and the wider family of port emission incentive schemes.