Bus: DEFRA 🇬🇧

💡 High-Level Description:

DEFRA's methodology for calculating the carbon footprint of bus travel is based on standardized emission factors published by the UK government. These factors are derived from extensive national data sources and provide a reliable basis for estimating greenhouse gas emissions from different types of bus transportation.

DEFRA's methodology takes into account various bus categories, including local buses operating within and outside London, as well as long-distance coaches. Emissions are calculated based on factors such as fuel consumption, average occupancy rates, and energy efficiency. Additionally, DEFRA offers flexibility in emissions reporting by supporting two energy scopes: Tank-to-Wheel (TTW) and Well-to-Wheel (WTW), with WTW being the default option for a more comprehensive lifecycle assessment.

By leveraging DEFRA's well-established reporting framework, businesses and policymakers can ensure consistent and transparent carbon accounting for bus travel, aligning with UK environmental reporting regulations and sustainability strategies.

API Request

{
  "expand": [
    "items"
  ],
  "items": [
    {
      "type": "bus",
      "external_reference": "test_1",
      "origin": "London",
      "destination": "Bristol",
      "bus_type": "coach",
      "number_of_travelers": 3,
      "energy_scope": "wtw",
      "methodology": "DEFRA"
    }
  ]
}

API Request Items

• "type": "bus" (required)

• "methodology": "DEFRA" (required)

• "external_reference": A unique identifier linking the emissions result to the requested item. Useful for multi-item requests as order is not guaranteed. Maximum length: 128 characters.

• "number_of_travelers": Minimum value is 1. Default is 1.

• "origin": Supports various formats including postal addresses, IATA/ICAO codes, UN/LOCODEs, or latitude/longitude coordinates.

• "destination": Same format support as "origin".

• "distance_in_km": If provided, overrides origin and destination. Otherwise, distance is auto-calculated.

• "bus_type": Specifies the type of bus. Options:

  • "local_bus_not_london"

  • "local_bus_london"

  • "average_local_bus" (default)

  • "coach"

• "energy_scope": Defines the emissions boundary:

  • "wtw" (Well-to-Wheel, default, full lifecycle emissions)

  • "ttw" (Tank-to-Wheel, tailpipe emissions only)

Default Values

• "bus_type": "average_local_bus"

• "energy_scope": "wtw"

Sample API Response

{
    "carbon_quantity": 15240,
    "carbon_unit": "gram",
    "items": [
        {
            "carbon_quantity": 15240,
            "carbon_unit": "gram",
            "external_reference": "test_1",
            "type": "bus",
            "methodology": "DEFRA",
            "distance": 190.0,
            "distance_unit": "kilometer"
        }
    ]
}

Bibliography

• UK Government. "Greenhouse Gas Reporting: Conversion Factors 2024." Department for Business, Energy & Industrial Strategy, 2024. https://www.gov.uk/government/publications/greenhouse-gas-reporting-conversion-factors-2024.