Car: DEFRA πŸ‡¬πŸ‡§

πŸ’‘ High-Level Description

The Department for Environment, Food & Rural Affairs (DEFRA) of the UK has been a stalwart in environmental governance and establishing methodologies across various sectors. Within the car sector, DEFRA's methodology focuses keenly on providing robust and comprehensible metrics for carbon emissions. Recognizing the massive contribution of vehicles to the UK's carbon footprint, DEFRA's guidelines are tailored to encompass the diverse range of vehicles on the roads, from compact cars to SUVs.

DEFRA's approach not only accounts for direct emissions derived from fuel combustion but also considers the broader life-cycle emissions of vehicles, including manufacturing, maintenance, and disposal. Their methodology, backed by extensive research and consultation with automotive industry experts, provides a solid foundation for the UK's policy-making, encouraging sustainable car manufacturing and usage. Through DEFRA's efforts, consumers, manufacturers, and policymakers are better equipped to make environmentally conscious decisions regarding transportation.

Versioning: Use methodology_version to pin a specific Conversion Factors year (e.g., "2024"). If omitted, SQUAKE uses the latest supported year.


Sample API Request

{
  "expand": ["items"],
  "items": [
    {
      "type": "car",
      "methodology": "DEFRA",
      "external_reference": "string",
      "origin": "Frankfurt am Main, Germany",
      "destination": "Berlin, Germany",
      "fuel_type": "hev",
      "car_type": "dual_purpose_4x4",
      "energy_scope": "ttw",
      "methodology_version": "2024"
    }
  ]
}

API Request Items

  • "type": "car" (required)

  • "methodology": "DEFRA" (required)

  • "methodology_version": DEFRA Conversion Factors year (e.g., "2024"). Optional; if omitted β†’ latest supported year.

  • "external_reference": Unique identifier to correlate responses (max 128 chars).

  • "origin" / "destination": Postal, IATA/ICAO, UN/LOCODE, or "lat,lon"; SQUAKE resolves distance.

  • "distance_in_km": If present, overrides origin/destination resolution.

  • "fuel_type": "petrol", "diesel", "hev", "phev", "electricity", "average" (default: "average").

  • "acriss_car_type": ACRISS segment letters (e.g., C,D,E,F,G,H,I,J,L,M,N,P,R,S,U,W,X,O). Mutually exclusive with "car_type".

  • "sipp_car_type": If acriss_car_type not passed, can be used to infer class. Mutually exclusive with "car_type".

  • "car_type": "mini", "supermini", "lower_medium", "upper_medium", "executive", "luxury", "sports", "dual_purpose_4x4", "mpv", "small", "medium", "large", "average" (default: "average").

  • "energy_scope": "wtw" (default) or "ttw".


Default Values

  • "fuel_type": "average"

  • "car_type": "average"

  • "energy_scope": "wtw"

  • "methodology_version": latest supported DEFRA year


Sample API Response

{
  "carbon_quantity": 10764,
  "carbon_unit": "gram",
  "items": [
    {
      "carbon_quantity": 10764,
      "carbon_unit": "gram",
      "external_reference": "string",
      "type": "car",
      "methodology": "DEFRA",
      "methodology_version": "2024",
      "distance": 110.0,
      "distance_unit": "kilometer"
    }
  ]
}

Versions

  • Behavior: If methodology_version is omitted, SQUAKE automatically applies the latest supported DEFRA Conversion Factors year. Pin a specific year for reproducibility and auditability.


Bibliography

  • UK Government β€” Greenhouse gas emissions: Research & statistics: https://www.gov.uk/environment/greenhouse-gas-emissions#research_and_statistics

  • Bramwell, R., et al. (2024). Government Greenhouse Gas Conversion Factors for Company Reporting β€” Methodology. (Methodology paper PDF).

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