Proposals should develop a comprehensive set of harmonised emission factors for the transport sector (freight and passenger), covering GHG emissions (CO2 equivalent) of transport and logistics operations. Proposals should address values for the entire transport/logistics chain and take up the full energy lifecycle (Well-To-Wheel/Wake).

Emission factors that relate the amount of GHG emission to the unit of energy consumed (for an energy-based calculation), or to the amount of GHG activity (for an activity-based calculation) are the basis of any GHG calculation. The increased efforts for measuring effects of climate change in various segments of the transport sector resulted in a range of values developed within the organisational structures of different transport modes, research entities and countries. Some of this work led to legitimate testing and development of the methodologies for the calculation and use of emission factors, or the generation of values that represent fuel specifications for given applications. However, much of it has merely resulted in a proliferation of apparently similar values creating confusion in the marketplace and bearing the risk of selection of sources/values purely on the basis of what is beneficial to the individual entity rather than what is correct.

This problem becomes more important in conjunction with the development of a wide set of technical solutions combating climate change, particularly the new and increasingly complex zero and low carbon energy mixes, including e- and biofuels. These solutions are deployed in the market very often with the support of dedicated financial mechanisms and programs, based on the estimated GHG emission reduction associated with the specific fuel technologies. Not only is it important for the climate impact that the emission calculations are ‘correct’ (There may be no such thing as a 100% correct value, but it is essential there is a consensus and linked convention based around values within an agreed, small uncertainty threshold.), but when dealing with large amounts of transport energy even a small difference over an emission factor value can lead to a significant difference in the associated financial transaction. Without an agreed and validated set of default emission factors for a wide range of the most common energy sources and a mechanism whereby legitimate variations or new energy carriers can be regularly updated, many actions based on calculating GHG emission reduction can be considered to be a risk of conflict and associated legal dispute.