Increase in Wltp's Co2 Emissions from Vehicles Based on European Certification Datasets

A new vehicle certification procedure (WLTP) was introduced in European Union (EU) in 2017. However, a limited studies evaluated the actual impact on CO2 emissions for different vehicle technologies and categories. This study analyses data from vehicles certified and registered in the EU in 2019 and 2020. On average, for vehicles sold in 2020, the increase was 21% for passenger cars and 27% for vans. Diesel vehicles are impacted more than gasoline and vans more relative to passenger cars for the same fuel. Conventional hybrid vehicles (NOVC-HEV) are impacted by 27% and plug-in hybrid vehicles (OVC-HEV) between 11% (in 2019) and 0% (in 2020).. Models employed showed that CO2 increases are mainly due to the higher test mass and more realistic road load coefficients that result in higher cycle energy demand. Comparisons to previous model-based estimates confirmed the impacts of the procedure both in terms of absolute increases and variability