Documentation

Calculation Methodology

Understanding how CII, EU ETS, and FuelEU metrics are calculated

Data Source

All calculations are based on data from the common_consumption_log_data collection in MongoDB. Each record represents a reporting period (typically daily) with:

imo - Vessel IMO number
voyageName - Voyage identifier
portOfOrigin / portOfDestination - Port and UN/LOCODE
totalCo2(T) - CO2 emissions in tonnes
distanceOverGround(Nm) - Distance in nautical miles
ciiAttained / ciiRequired / ciiRating - Pre-calculated CII values

CII (Carbon Intensity Indicator)

What is CII?

CII measures the carbon intensity of ship operations - how efficiently a ship transports cargo relative to CO2 emissions. It's an IMO regulation effective from January 2023.

Formula

CII = CO₂ Emissions (grams) / (Capacity × Distance)

Where Capacity = DWT or GT depending on ship type

Rating Scale

Rating	Description	Action Required
A	Superior performance	None - exceeds requirements
B	Good performance	None - meets requirements
C	Moderate performance	None - at threshold
D	Below standard	Corrective action plan within 3 years
E	Inferior performance	Immediate corrective action required

Data Note

CII values displayed in this dashboard are pre-calculated in the source data. The dashboard reads the ciiAttained, ciiRequired, and ciiRating fields directly from the database.

CII Playground

Experiment with CII calculations using different ship parameters and fuel consumption data.

Ship Type

Capacity (DWT)

Year

Calculated Values

Reference CII9.54 gCO2/t-NM

Reduction Factor (2025)9%

Required CII8.68 gCO2/t-NM

Rating Boundaries

AAttained CII≤ 7.20

BAttained CII≤ 8.16

CAttained CII≤ 9.29

DAttained CII≤ 10.33

EAttained CII> 10.33

Formula Applied

Reference CII = 1984 × 55,000^(-0.489) = 9.54

Required CII = 9.54 × (1 - 9%) = 8.68

Implementation

Backend Services

Services

FleetService.ts - Fleet-level EU ETS & FuelEU aggregations
VesselService.ts - Vessel voyage & leg calculations
portClassifier.ts - EU/EEA port detection logic
fuelEUCalculator.ts - FuelEU GHG intensity calculation

Key Functions

isEUPort() - Check if UN/LOCODE is EU/EEA
extractVoyageLegs() - Break voyage into port-to-port segments
calculateLegsETSEmissions() - Sum covered emissions by leg
calculateFuelEUCompliance() - Calculate WtW GHG intensity & penalty