Towards zero CO2 emissions: Insights from EU vehicle on-board data
Jaime Suárez, Alessandro Tansini, M.A. Ktistakis, Andrés L. Marín, Dimitrios Komnos, Jelica Pavlovic, Georgios Fontaras
Abstract
Transport tailpipe CO 2 emissions remain central to the EU's transport decarbonisation efforts. This study presents a data-driven methodology to assess Real-World (RW) CO 2 emissions based on On-Board Fuel and Energy Consumption Monitoring (OBFCM) data from 7.7 million passenger cars registered in the EU between 2021 and 2023. OBFCM data provide detailed insights into actual fuel consumption and CO 2 emissions, and the annual mileage, across different vehicle technologies. By analysing three years of OBFCM data, we identify RW-CO 2 emission patterns and variability driven by key technical, behavioural and geographical factors. Multivariable regression models yield emission factors for each powertrain/fuel type combination, enabling the estimation of total RW emissions for the entire fleet of newly registered vehicles per year. Vehicle mass and engine power are key drivers of RW CO 2 emissions variability for Internal Combustion Engine Vehicles (ICEVs) and Hybrid Electric Vehicles (HEVs), while electric driving share dominates for Plug-in Hybrid Electric Vehicles (PHEVs). Average in-use EU fleet emissions are estimated at 166 g/km for petrol and 170 g/km for diesel ICEVs; 149 g/km for petrol and 190 g/km for diesel HEVs; and 131 g/km and 150 g/km for petrol and diesel PHEVs, which show the highest CO 2 reduction potential. Annual RW emissions from newly registered vehicles in 2021 total 20.9 Mt., 18.7 Mt. for 2022 registrations and 20.5 Mt. in 2023, reflecting evolving fleet composition, fuel efficiency and annual distance. This methodology offers a robust empirical basis for quantifying RW CO 2 emissions and for monitoring the effectiveness of respective policy measures. • Fuel consumption data from 7.7 M EU cars enable fleet-level real-world CO2 analysis • Real-world emissions variability depends on vehicle technology and driving factors • Plug-in vehicles show the highest CO2 reduction potential, but large variability • Mass, engine power and electric share drive emissions across powertrains and fuels • Total RW CO 2 from new EU cars was 20.9 Mt. in 2021, 18.7 Mt. in 2022 and 20.4 in 2023