DEFRA freight transport methodology


This page represents a greenhouse gas emissions methodology for the freighting of goods. The data and calculation methodology originates from the UK government department DEFRA, as published in their most recent Greenhouse Gas Conversion Factors for Company Reporting[1] documentation.

The methodology

Emissions model

The emissions methodology is based upon emissions factors which describe the rate at which greenhouse gas emissions are produced during the freighting of goods in relation to distance travelled and the quantity of goods freighted. These emissions factors represent emissions associated with individual units of freight, which can be contrasted with similar transport-related emissions factors which describe emissions on the basis of entire vehicles (e.g. entire ship or lorry).

Emissions - expressed in terms of mass (e.g. kg) - are calculated by multiplying these rates (mass emitted per mass per distance; e.g. kg CO2 per tonne km) by a distance (e.g km) and quantity (e.g. tonne) freighted.

Model data

The rate at which freight transportation produces greenhouse gas emissions varies with the mode of transport, depending on factors such as the fuel efficiency (i.e. the distance acheived per unit of fuel consumed) of the particular type of vehicle (e.g. lorry, plane, train, ship) as well as the typical freight loading. Fuel efficiency may be related factors such as the type of fuel used (e.g. petrol, diesel, biofuel, electricity) and the physical dynamics of the transportation context (i.e. road, rail, water, air). The loading of freight indicates the extent to which the emissions of the entire vehicle can be 'shared' between units of freight. Therefore, emissions factors for a broad range of generalised freight transport scenarios are provided.

A total of 75 specific types of freight transport scenarios are represented and are differentiated by transport type (i.e. ship, plane, rail, van, heavy goods vehicle), subtype (e.g. 'petrol' versus 'diesel' vans, 'crude tanker' versus 'general cargo' in shipping) and vehicle size (e.g. gross vehicle weight, deadweight tonnes, TEU, CEU).

Each freight transport type is represented by six distinct emissions factors which differentiate greenhouse gas emissions into the following types:

  • direct CO2 emissions: carbon dioxide emissions produced during freighting, i.e. fuel combustion
  • direct CH4 emissions: methane emissions produced during freighting, i.e. fuel combustion
  • direct N2O emissions: nitrous oxide emissions produced during freighting, i.e. fuel combustion
  • total direct emissions: all direct emissions, i.e. CO2 + CH4 + N2O
  • indirect emissions: emissions associated with stages in the fuel production chain such as raw material extraction and fuel delivery
  • total or 'life cycle': the total of direct and indirect emissions
Each of these emissions factors are expressed in terms of kg CO2e per tonne km.

Activity data required

According to this methodology, greenhouse gas emissions are directly proportionate to distance and quantity (mass) of goods freighted, both of which therefore must be specified in order to make an emissions calculation.

Calculation and results

This emissions calculated by this methodology represent those per unit of freight and therefore should be considered attributable to the freighting of the specified quantity of freight only (rather than, say, the emissions attributable to the entire vehicle(s) on which it was transported).

The methodology calculates several emissions quantities including direct CO2, CH4, N2O as well as indirect and total life cycle emissions. All quantities in this methodology are expressed in terms of CO2e - the quantity of CO2 which would exert the same atmospheric warming effect and the emissions quantity.

Additional information

Great circle distance 'uplift' factors

Following IPCC advice, the DEFRA methodology stipulates that flight distances which are defined as direct 'great circle' distances between two locations should be inflated by 9% in order to account for the typical indirect routing of actual flights and deviations related to congestion. The calculations for air travel made herein assume that the distance specifed is known to be the actual distance flown - rather than the distance estimated on the basis of the Great Circle - and therefore this adjustment factor is not applied. In order to make calculations based on Great Circle estimates between two locations (airports or specifed by latitiude/longitude) see the Great Circle route methodology.

Related methodologies

Other DEFRA transport methodologies available representing road vehicles differentiated by size and market segment, heavy goods vehicles and passenger transport are also available.

Useful links

  1. DEFRA / DECC's Greenhouse Gas Conversion Factors for Company Reporting homepage

IL0VF690FB0G heavy goods vehicle, all, uk average
O78B8Y7BPMYS heavy goods vehicle, articulated, 3.5-33 t
3NCTR4YMZT93 heavy goods vehicle, articulated, above 33 t
UD38UJAZE63Z heavy goods vehicle, articulated, uk average
TVAK6VS7A0JS heavy goods vehicle, rigid, 3.5-7.5 t
VVCCUPBOD22I heavy goods vehicle, rigid, 7.5-17 t
V79BPQIJWM90 heavy goods vehicle, rigid, above 17 t
AE9HLGCZHQYB heavy goods vehicle, rigid, uk average
2XD89BTTKIR5 plane, domestic
THLRNABYGWOH plane, long-haul international
3Y4EK4GUAGC2 plane, short-haul international
A1CQC2KQBOAL rail, diesel/electric
3Q41I028HH4R ship, bulk carrier, 0-9999 dwt
5I3YJHY90E5W ship, bulk carrier, 10 000-34 999 dwt
08NBWIPRXQM5 ship, bulk carrier, 100 000-199 999 dwt
VM84Y6WY0E6J ship, bulk carrier, 35 000-59 999 dwt
XPYIJL8C6V48 ship, bulk carrier, 60 000-99 999 dwt
1PCW0EGTGVNY ship, bulk carrier, average
PABQ3SZLRZ0X ship, bulk carrier, over 200 000 dwt
T1E0JKKZVOEG ship, chemical tanker, 0-4999 dwt
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Name: DEFRA_freight_transport_methodology
Full path: /transport/defra/freight
Provenance: DEFRA