Updated fossil diesel fuel data
In order to ensure accurate and up to date greenhouse gas (GHG) emission baseline factors for the combustion of fossil diesel used in compression-ignition engines, NTM has reviewed various data sources where the emissions of diesel as transport fuel have been estimated from a life cycle perspective. The scope included emissions of GHGs from well to tank (wtt) and tank to wheel (ttw).
The rationale for this update is to ensure verifiable savings from a credible baseline when introducing diesel with different feedstock blends.
Throughout the recent life cycle assessment (LCA) studies, the span of the reported wtt GHG emission factors increases substantially from low to high. In a study from 2011, based on refineries in Sweden, the wtt-result was 6,7 g CO2 eq./MJ diesel. In the latest JRC-study, (Edwards et.al. version 5, 2020) the wtt-result was 18,9 g CO2 eq./MJ diesel, for European diesel. The latter LCA is based on a system expansion approach i.e., assuming marginal diesel production, thus resulting in a significant higher CO2 eq. emission factor per MJ fuel. These refineries can be considered as worst-case scenarios.
In order to provide a more representative value NTM have decided to adjust the previous international diesel baseline assumption of 9,5 g CO2 eq./MJ diesel which was according to the LCA study by Ahlvik & Eriksson to 13 g CO2 eq./MJ diesel. This value is in line with values reported to life cycle inventory databases. Real performance is likely to deviate significantly in different markets. Hence more accurate calculations require operational and verified data from the fuel supplier.
Presently there is an ongoing work to implement these new data and various data for fuels based on renewable feedstocks in NTMCalc.