EEXI (Energy Efficiency Existing Ship Index)
The Energy Efficiency Existing Ship Index (EEXI) is an IMO regulation, in force since 2023, that requires existing ships to meet a minimum energy-efficiency (CO₂-per-transport-work) standard based on their design — extending to the existing fleet the principle already applied to newbuildings under the EEDI. Each ship must calculate its attained EEXI and show it is below the required level for its type and size.
EEXI is a one-off, design-based requirement (unlike the operational, ongoing CII). Ships that do not comply typically achieve it by engine or shaft power limitation (EPL/ShaPoLi) — capping installed power to reduce speed and emissions — or by efficiency modifications. Together with the CII rating and the IMO Data Collection System, EEXI is part of the IMO's short-term measures to reduce shipping's carbon intensity, and it directly affects vessel operation, speed and technical management.
EEXI brought the whole existing fleet under a design-efficiency standard overnight, pushing many ships to power-limit their engines and cut speed. Combined with the operational CII, it is reshaping how ships are run and managed technically. For any operator of older tonnage it is a live compliance and performance issue, not a future one.
How is EEXI different from CII?
EEXI is a one-off design-based efficiency requirement; CII is an ongoing operational rating based on a ship's actual annual emissions.
How do ships comply with EEXI?
Usually by engine or shaft power limitation (capping power to reduce speed) or by energy-efficiency modifications.