> ## Documentation Index
> Fetch the complete documentation index at: https://docs.appliedaifoundation.org/llms.txt
> Use this file to discover all available pages before exploring further.

# 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](https://wwwcdn.imo.org/localresources/en/OurWork/Environment/Documents/Technical%20and%20Operational%20Measures/MEPC.1_Circ.684_Guidelines%20for%20Voluntary%20use%20of%20EEOI.pdf) — Guidelines for Voluntary Use of EEOI