Which units do freight and storage emission factors come in for the distance-based method in the Scope 3 guidance, and what goes wrong if I multiply by the wrong one?
In the Greenhouse Gas (GHG) Protocol's Scope 3 guidance, air, rail, road and bulk ship factors are per tonne-kilometre. Trucks of 16 tonnes and above also come per twenty-foot container (TEU) kilometre, as do container ships, and warehouses are per pallet-day. 1 TEU is 10 tonnes by default.
Table 4.2: the unit for each mode
- Air, in kilograms of carbon dioxide equivalent (CO2e) per tonne-kilometre: freighter, belly-freight and passenger plane, each short-haul and long-haul. The primary source is the carrier.
- Ship: container vessels of under 2,000 TEU, 2,000 to 5,000, 5,000 to 8,000 and over 8,000 are per TEU-kilometre. Bulk vessels of under 20,000 and over 20,000 deadweight tonnes are per tonne-kilometre. Default: 1 TEU = 10 tonnes.
- Rail, electric and diesel: per tonne-kilometre.
- Truck: van under 3.5 tonnes, 3.5 to 7.5, 7.5 to 16: per tonne-kilometre. 16 to 32 tonnes single axle, and over 32 tonnes tractor and trailer or flatbed: per tonne-kilometre and per TEU-kilometre. Default: 1 TEU = 10 tonnes.
- Warehouse, dry or refrigerated: per pallet-day, per TEU-day, per cubic metre-day or per kilogram-day. Default: 1 pallet = 1 square metre of floor space. An operator may also have a factor based on warehouse surface.
- Terminal: per tonne or per TEU, with 1 TEU = 10 tonnes.
The multiplication
Formula 4.6 multiplies, for each leg, the mass of goods in tonnes, or the volume, times the distance of that leg in kilometres, times the factor for the mode or vehicle type, and adds the legs. The guide says to take the quantity of goods in mass, including packaging and pallets, or in volume, and that the transport legs should be calculated separately and total emissions aggregated.
A unit slip in the guide itself
The guide's Example 4.2 prints its factor column as kilograms of CO2e per TEU-kilometre, with 0.2 for a rigid truck, 1.0 for long-haul air and 0.05 for a container ship. Its sums then multiply tonnes by those numbers: 6 tonnes x 4,000 kilometres x 0.05 = 1,200 kilograms for the ship. The sums only work if all three factors are per tonne-kilometre. At the guide's default of 1 TEU = 10 tonnes, a factor of 0.05 per TEU-kilometre gives 0.6 TEU x 4,000 x 0.05 = 120 kilograms. The guide says its figures are for example only. Our reading is that the slip is in the table heading, not in a real factor. Read your own factor's unit line before you use it.
12 tonnes of cargo, 5,000 kilometres by sea, example factor of 0.5 kilograms per TEU-kilometre
- Per TEU-kilometre: 12 / 10 = 1.2 TEU, then 1.2 x 5,000 x 0.5 = 3,000 kilograms of CO2e
- The same factor converted to per tonne-kilometre is 0.5 / 10 = 0.05, so 12 x 5,000 x 0.05 = 3,000 kilograms. The two agree
- Using 0.5 as if it were per tonne-kilometre: 12 x 5,000 x 0.5 = 30,000 kilograms, ten times too much
The 12 tonnes, 5,000 kilometres and the 0.5 factor are example numbers, not a published factor. The 10 tonnes per TEU is the guide's default.
What Senseible does here
Senseible reads fuel invoices and electricity bills into monthly records, so your own diesel and warehouse power show up once uploaded. A carrier's factor and its unit are in the carrier's report, which you keep alongside.
- Freight: Scope 3 category 4 or 9
- Intermodal containers: rail, road and sea
- Warehouse electricity per pallet position
- Free calculators
Last reviewed 2026-11-05. Units are as printed in the GHG Protocol's Technical Guidance. Carriers may use other container weights than the 10 tonne default, so ask the carrier for the weight they assumed.