Calculating and reporting your fleet’s greenhouse gas emissions

There are multiple factors to consider when planning to decarbonise your fleet. The first step is to start calculating your current fleet emissions. This will give you a baseline to work from and help you to identify where you can make carbon savings.  

Your organisation’s carbon dioxide equivalent (CO2e) footprint (or carbon footprint) is the amount of greenhouse gases (GHG) it emits in one year in tonnes. 

For road transport, the reportable GHGs are: 

• carbon dioxide (CO2) 
• methane (CH4) 
• nitrous oxide (N2O) 

Methane and nitrous oxide are reported in terms of their carbon dioxide equivalence using their global warming potential (GHG Protocol, GWP Values). It’s important to report your CO2e emissions as well as your CO2. This will make sure you meet national and international GHG reporting standards.   

You can report your road transport GHG emissions using the tank to wheel emission factors. These exclude any CO2e emissions relating to the extraction, refining and distribution of the fuels, known as well to tank factors. They also exclude emissions associated with the manufacture and disposal of the vehicles.  

Well to tank emission factors can be combined with tank to wheel factors to give well to wheel values. However, the fuel supplier should report the upstream emissions of well to tank.