{
  "name": "CII reference dataset",
  "licence": "CC BY 4.0",
  "attribution": "CII reference dataset by Full Ahead Maritime, CC BY 4.0 — https://fullaheadmaritime.com/cii-calculator",
  "source": {
    "referenceLines": "IMO MEPC.353(78)",
    "reductionFactors": "IMO MEPC.354(78)",
    "fuelCarbonFactors": "IMO MEPC.364(79)",
    "euEts": "Directive 2003/87/EC as amended by (EU) 2023/959"
  },
  "formula": {
    "attainedCii": "sum(fuel_t * cf) * 1e6 / (dwt * distance_nm)  [g CO2 / t-nm]",
    "requiredCii": "a * dwt^-c * (1 - Z/100)",
    "rating": "attained / required compared against the dd boundary vector"
  },
  "shipTypes": [
    {
      "id": "bulk",
      "label": "Bulk carrier (< 279,000 DWT)",
      "a": 4745,
      "c": 0.622,
      "d": [
        0.86,
        0.94,
        1.06,
        1.18
      ]
    },
    {
      "id": "tanker",
      "label": "Tanker",
      "a": 5247,
      "c": 0.61,
      "d": [
        0.82,
        0.93,
        1.08,
        1.28
      ]
    },
    {
      "id": "container",
      "label": "Container ship",
      "a": 1984,
      "c": 0.489,
      "d": [
        0.83,
        0.94,
        1.07,
        1.19
      ]
    },
    {
      "id": "general",
      "label": "General cargo ship",
      "a": 31948,
      "c": 0.792,
      "d": [
        0.83,
        0.94,
        1.06,
        1.19
      ]
    },
    {
      "id": "reefer",
      "label": "Refrigerated cargo carrier",
      "a": 4600,
      "c": 0.557,
      "d": [
        0.78,
        0.91,
        1.07,
        1.2
      ]
    },
    {
      "id": "roro",
      "label": "Ro-ro cargo ship",
      "a": 1686,
      "c": 0.498,
      "d": [
        0.76,
        0.89,
        1.08,
        1.27
      ]
    }
  ],
  "reductionFactorsPercent": {
    "2023": 5,
    "2024": 7,
    "2025": 9,
    "2026": 11,
    "2027": 13
  },
  "fuelCarbonFactors": [
    {
      "id": "hfo",
      "label": "HFO",
      "cf": 3.114
    },
    {
      "id": "vlsfo",
      "label": "VLSFO / LFO",
      "cf": 3.151
    },
    {
      "id": "mgo",
      "label": "MGO / MDO",
      "cf": 3.206
    },
    {
      "id": "lng",
      "label": "LNG",
      "cf": 2.75
    },
    {
      "id": "methanol",
      "label": "Methanol",
      "cf": 1.375
    }
  ],
  "euEtsPhaseIn": {
    "2023": 0,
    "2024": 0.4,
    "2025": 0.7,
    "2026": 1,
    "2027": 1
  },
  "updated": "2026-08-14"
}