Skip to main content

Heavy duty vehicle, greenhouse gas and kWh calculations

This is a standardised approach to estimating heavy duty vehicle (HDV) fleets’ CO2e emissions. HDV fleets usually have complete and accurate records of both fuel usage and mileage, which is usually recorded in kilometres. 

The methods are presented in order of accuracy. You should use the most accurate methodology for each of your vehicles.  

Method one: fuel consumption data

If you have comprehensive fuel consumption data from fuel card records and/or a bunkered fuel system, you should calculate the GHG emissions and energy used by applying the factors in the table below to the quantity of fuel consumed.

The diesel and petrol factors are for the biofuel blends sold in the UK.

Table 8 – Emission factors for different type of fuel

FuelUnitsGHG Scopekg CO2e/unitkg CO2e/kWhkWh/unit
PetrolLitres12.100.229.545455
DieselLitres12.510.2410.45833
CNGkg12.56250.1814.23611
LNGkg12.58190.1814.34389
LPGlitres11.560.217.428571
ElectricitykWh20.2120.191.0000
Electricity T&DkWh30.0170.021.0000

Methods two to five: mileage data but no fuel data

If your fuel data is unavailable, you should base your methodology on the distance you travelled (miles or km) along with the appropriate conversion factor. The conversion factor will depend on the additional data available (see table below).

 

Table 9 – Overview of HDV GHG methodologies two to five

GHG MethodologyMileageArtic/rigidGVWLoad Factor
Method two✔️✔️✔️✔️
Method three✔️✔️✔️
Method four✔️✔️
Method five✔️

To convert from kgCO2e/km to kWh/km the GHG factor is divided by the fuel factor (diesel) in kgCO2e/kWh to give kWh/km.

Average HDV GHG emissions are:

  • Average HDV GHG emissions – any type (not refrigerated) – 0.8720 CO2e km-1
  • Average HDV GHG emissions – ay type (refrigerated) – 1.0088 kg CO2e km-1

Table 10 - Rigid HDV average GHG emissions (not refrigerated)

GVW ClassGVW% Load factorkg CO2e km-1
Class 1> 3.5-7.5t0%0.4522
50%0.4910
100%0.5299
UK Average 46%0.4856
Class 2>7.5-17t0%0.5408
50%0.6172
100%0.6935
Class 3>17t0%0.7468
50%0.9083
100%1.0699
UK Average 54%0.9743
AverageUnknownUK Average 53%0.8231

Table 11 - Rigid HDV average GHG emissions (refrigerated)

GVW ClassGVW% Load factorkg CO2e km-1
Class 1> 3.5-7.5t0%0.5384
50%0.5847
100%0.6311
UK Average 46%0.5783
Class 2>7.5-17t0%0.6439
50%0.7350
100%0.8261
UK Average 39%0.7059
Class 3>17t0%0.8888
50%1.081
100%1.274
UK Average 54%1.1603

Table 12 - Articulated HDV average GHG emissions (not refrigerated)

GVW ClassGVW% Load factorkg CO2e km-1
Class 1> 3.5-33t0%0.6156
50%0.7664
100%0.9173
UK Average 44%0.7664
Class 2>33t0%0.6325
50%0.8384
100%1.0444
UK Average 62%0.9126
AverageUnknownUK Average 61%0.9126

Table 13 - Articulated HDV average GHG emissions (refrigerated)

GVW ClassGVW% Load factorkg CO2e km-1
Class 1> 3.5-33t0%0.7118
50%0.8867
100%1.0616
UK Average 44%0.8867
Class 2>33t0%0.7310
50%0.9698
100%1.2087
UK Average 62%1.0558

Many organisations have grid electricity supplied from renewable sources backed by Renewable Energy Guarantees of Origin certificates or grid biomethane backed by Renewable Transport Fuel Obligation certificates.   

You can report the GHG emissions of the electricity or gas in line with the ‘market-based’ consumer value calculated by the supplier. For example, zero gCO2e/kWh of 100% renewable electricity. This should also be reported alongside the ‘location-based’ national figure.    

This is because the zero emissions benefit of the electricity or gas has already been accounted for in the national UK grid figure. You can only use this benefit once. This also applies when the carbon factor for other consumers has been adjusted upwards to compensate.  

The requirement to do this is fully documented in:

  • HM Government: environmental reporting guidelines: including streamlined energy and carbon reporting guidance. March 2019, pages 48-49  

    Where organisations have entered into contractual arrangements for renewable electricity, such as through power purchase agreements or the separate purchase of renewable energy guarantees of origin, or consumed renewable heat or transport certified through a UK Government scheme and a want to reflect a reduced emission figure based on its purchase. In this case you can show the relevant report using a ‘market-based’ reporting approach. You can show this as well as the ‘location-based’ grid-average figures. It’s also worth specifying whether the renewable energy you use is additional, subsidised and supplied directly, including on-site generation, or through a third party. A similar ‘dual reporting’ approach should be taken for biogas and biomethane (including ‘green gas’).

  • GHG protocol, scope 2 guidance, corporate standard, section 1.5.1, page 8  

    Text: “If your company has different operations in markets which provide products or supplier-specific data in the form of contractual instruments, you should report scope 2 emissions in two ways and label each result according to the method: one based on the location-based method, and one based on the market-based approach. Using this method is also called ‘dual reporting’.” 

  • Time specific emission factors are permitted. The HM Government environmental guidelines for reporting state:   

    Where available, time specific (hour by hour) grid average emission factors should be used in order to accurately reflect the timing of consumption and the carbon intensity of the grid.

    The carbon intensity of the grid varies throughout the day and year. The grid data is publicly available in half hourly intervals. However, organisations may find it difficult to provide half hourly consumption data unless they are billed in this way.   

    If your company generates renewables on-site or locally, your company is known as a zero or low carbon supply organisation.  

    For example, it may do this by using photovoltaics or wind with a localised electricity grid.

Previous section
1.3. Car and van greenhouse gas and kWh calculations
Next section
2.0. Rationalise your fleet