Is Ecoscore to be preferred over the European 'Clean Vehicle' methodology?
Both the Ecoscore and the Clean Vehicle methodology grant a score to individual vehicles depending on their impact on the environment. In the Ecoscore methodology, this score takes into account tailpipe emissions, as well as indirect emissions due to the extraction, production and distribution of the fuel or electricity. The emissions which are included are greenhouse gas emissions (CO2, CH4, N2O) and emissions influencing air quality (NOx, PM, CO, NMHC and SOx). Also the influence of noise is taken into consideration. In the Clean Vehicle approach, only the tailpipe emissions are included, more specifically of CO2, NOx, PM and NMHC. Also the direct energy use of the vehicle is taken into account in the score. This score is expressed as a cost over the vehicle's lifetime. Different cost types are added for calculating this cost (market prices and societal costs) of energy consumption, CO2 and the considered pollutants. This implies that the emissions of CO2, which are linked to the energy consumption, have a very strong weight in the final score, while the emissions with impact on air quality only have a limited influence. By using this Clean Vehicle methodology, fuel-efficient vehicles emitting low levels of CO2, are favoured strongly. This gives a benefit especially to diesel cars. The use of a particulate filter in these cars is even discouraged because the fuel consumption increases slightly and the benefit of the lower PM emissions hardly counts in the overall score. Also cars on compressed natural gas, which obtain good Ecoscore results, are punished in the Clean Vehicle methodology because of their relatively high CO2 emissions and low energy density.
Because of these arguments, Ecoscore is still the preferred methodology over the Clean Vehicle methodology to give an environmental score to a vehicle and to use this as the basis for a sustainable vehicle purchase decision. More detailed information can be found in the full report.