EEOI

Energy Efficiency Operational Indicator — by TEU and by weight, when to use which.

EEOI (Energy Efficiency Operational Indicator) measures CO₂ per transport work — i.e. per unit of cargo actually moved per nautical mile. Unlike CII, which uses a ship’s design capacity in the denominator, EEOI uses what the ship is actually carrying.

Two flavours

The vessel detail page shows EEOI in two units, depending on ship type:

EEOI by TEU (containers)

EEOI_TEU = Total CO₂ (g) / (TEU carried × Distance NM)

Reported in gCO₂ / TEU-NM. Used for container ships where cargo is volumetric.

EEOI by weight (bulk and general cargo)

EEOI_W = Total CO₂ (g) / (Cargo weight (t) × Distance NM)

Reported in gCO₂ / tonne-NM. Used for bulkers, tankers, and general cargo where cargo is mass-based.

Why both?

Container vessels report cargo in TEU; bulkers in tonnes. A single weight-based EEOI doesn’t make commercial sense for containers (a TEU of feathers and a TEU of bricks are very different). Showing both lets the dashboard work for any fleet mix.

Supporting figures

Alongside the EEOI numbers, the vessel detail page shows:

• Transport work — TEU-NM or T-NM
• Total CO₂ — tonnes
• Total distance — NM
• Average cargo per voyage — TEU or tonnes

These let you sanity-check the input ratio.

Implementation

EEOI is computed in the vessel detail client component using fields from the consumption log: cargoWeightT, cargoTeu, distanceOverGroundNm, totalCo2T. There’s no separate calculator file — it’s a straightforward division with type-aware unit choice.

Relationship to CII

	CII	EEOI
Denominator	Capacity (DWT/GT) — design	Cargo carried (TEU or t) — actual
Used for	Compliance rating (A–E)	Operational efficiency tracking
Regulator	IMO	Industry standard (not regulated)
When more useful	Year-end compliance	Voyage-by-voyage efficiency

EEOI is not a regulatory metric — it’s an operational benchmark that sits alongside CII. The platform shows both because they answer different questions.

Reference

• IMO MEPC.1/Circ.684 — Guidelines for Voluntary Use of EEOI