GLEC Framework v3.2 and ISO 14083: How to Calculate Freight Emissions

Freight is one of the larger Scope 3 categories for most manufacturers and retailers, and the core Scope 1 for every carrier. Two documents now define how to count it. ISO 14083:2023, *Greenhouse gases: quantification and reporting of greenhouse gas emissions arising from transport chain operations*, is the international standard. The GLEC Framework, published by Smart Freight Centre, integrates ISO 14083 and adds the default factors and worked methods that make it usable. Its current edition is v3.2, revised and updated in October 2025.

What changed in GLEC v3.2

If your figures are on v3.0 or v3.1, the method is the same; the defaults and some regional fuel factors moved. Record which edition each figure used, so a year-on-year comparison is not distorted by a factor change.

The five ideas you need

• Well-to-wheel (WTW). The full energy life cycle: well-to-tank (WTT), producing and delivering the fuel or electricity, plus tank-to-wheel (TTW), burning it in the vehicle. ISO 14083 and GLEC report WTW. For air and sea it is called well-to-wake.
• Transport chain element (TCE). One section of a journey with a single vehicle or one hub: a truck leg, a rail leg, a port, a warehouse. A consignment's emissions are the sum of its TCEs.
• Transport operation category (TOC). A group of similar operations (say, a carrier's long-haul articulated trucks on one network) whose emissions and activity are pooled to give one intensity. Hubs have hub operation categories.
• Transport activity, in tonne-kilometres. Mass moved times distance. One tonne-km is one tonne carried one kilometre. For charging consignments, distance is the shortest feasible distance or the great-circle distance, not the kilometres a vehicle happened to drive.
• Emission intensity. A TOC's emissions divided by its transport activity, in g CO2e per tonne-km. It is the number a carrier should be able to give a shipper.

Worked example: one consignment by road, through one hub

An illustrative carrier runs a fleet of diesel articulated trucks in Europe. In a year the fleet burns 410,000 litres of diesel and performs 20 million tonne-km. A shipper sends an 18-tonne consignment 640 km (shortest feasible distance) on that network, and it passes through one cross-dock.

Step 1: the fleet's emissions

GLEC v3.2 Module 1 gives European diesel 4.19 kg CO2e per kg WTW and 3.22 kg per kg TTW, at a density of 0.83 kg per litre. That is 3.478 kg CO2e per litre WTW and 2.673 kg TTW. The fleet's WTW emissions are 410,000 × 3.478 = 1,425,857 kg CO2e, and its TTW emissions 1,095,766 kg.

Step 2: the fleet's intensity

Divide by transport activity: 1,425,857 kg ÷ 20,000,000 tonne-km = 71.3 g CO2e per tonne-km WTW (54.8 g TTW). That intensity is the carrier's TOC value, and the shipper should ask for it in place of a generic default.

Step 3: the consignment's legs

On a TTW basis the road leg would be 631 kg, so reporting TTW alone would understate the leg by about 23%. If the shipper had used a generic default intensity instead of the carrier's, the result could differ in either direction, which is why the data hierarchy matters.

The data hierarchy

1. Primary data. The carrier's own measured fuel or electricity and its own transport activity, as in the example. This is what a carrier should use for its Scope 1, and what a shipper should ask its carriers for.
2. Modelled data. Energy use estimated from vehicle type, load, route and speed with a documented model. Better than defaults, but the model and its assumptions must be stated.
3. Default data. The GLEC default intensities by mode and region. Use them only when nothing better exists, and disclose it: they cannot show the effect of a carrier's efficiency.

Distance adjustments

• Air. GLEC v3.2 converts a great-circle distance to a flown distance by adding 95 km.
• Sea containers. Actual distances average about 15% above the shortest feasible route. GLEC's own container intensities already include this, so do not add it twice.
• Road. When a shipper estimates transport activity from planned distances, GLEC applies a factor of 1.05.

CountEmissionsEU: ISO 14083 becomes the EU method

The EU has adopted CountEmissionsEU as Regulation (EU) 2026/1030, published in the Official Journal on 12 May 2026. It sets one method for calculating transport emissions, based on EN ISO 14083:2023 and on a well-to-wheel basis. It does not oblige anyone to calculate: it applies when a company calculates and discloses transport emissions, whether by law, by contract or voluntarily. Most provisions apply from 2 December 2030. Before then the Commission is to set up a database of default intensities and a free online calculation tool.

For carriers and shippers serving EU customers, the practical message is that an ISO 14083 and GLEC-based inventory built now is already on the method the EU will expect.

Who reports what

For a carrier, the fuel its own vehicles burn is Scope 1 and the electricity it buys is Scope 2; the well-to-tank part is Scope 3, category 3. For a shipper, the same transport is Scope 3: category 4 for inbound transport of what it buys and for any outbound transport it pays for, category 9 for downstream transport it does not pay for. Product footprints include inbound transport on a WTW basis; the PACT guide shows where it sits.

A checklist for your next freight inventory

• List each lane as transport chain elements, including hubs.
• Ask each carrier for a WTW intensity per TOC, the edition of the factors behind it, and whether it is primary, modelled or default.
• Use shortest feasible or great-circle distances for consignments, with the mode's adjustment where GLEC requires it.
• Report WTW, and keep TTW alongside if your customers or regulators ask for it.
• Record the GLEC edition and the data tier on every figure.

ZeroCarbon's freight engine implements these GLEC v3.2 methods, from TOC intensities and hub intensities to EV charging losses and multi-drop allocation, and keeps the factor and edition on each leg. You can try a road-freight calculation without an account through the free emissions API. Today it covers India, UK and US factors. For carrier-specific intensities across your lanes, request a workspace.