The Gap Between Real-world CO2 Emissions and WLTP Values for European Cars

The European Commission has released a comprehensive report comparing real-world CO2 emissions of vehicles to the official WLTP (Worldwide harmonised Light vehicle Test Procedure) values. This comparison highlights the discrepancies between laboratory testing and actual on-road performance, emphasizing the importance of realistic emissions data for policy-making and consumer trust.

Key Findings:

1. Average CO2 Emissions and Fuel Consumption:
   • Petrol Cars: Real-world CO2 emissions are 23.7% higher than WLTP values, with real-world fuel consumption at 7.89 l/100 km compared to WLTP's 6.38 l/100 km.
   • Diesel Cars: Real-world CO2 emissions are 18.1% higher than WLTP values, with real-world fuel consumption at 6.88 l/100 km compared to WLTP's 5.82 l/100 km.
   • Plug-in Hybrid Electric Vehicles (PHEVs): Real-world CO2 emissions are significantly higher, with discrepancies of 238% for petrol PHEVs and 312% for diesel PHEVs compared to WLTP values.
2. Factors Affecting the Discrepancy:
   • Utility Factor for PHEVs: PHEVs are driven less in electric mode and recharged less frequently than assumed, leading to a significant gap.
   • Vehicle Weight: Heavier vehicles like SUVs and luxury cars show a larger gap between real-world and WLTP emissions, exacerbating their higher emissions.
3. Fleet-wide and Manufacturer-level Assessments:
   • The gap varies across manufacturers and vehicle types, with some petrol cars showing a gap ranging from 10% to 32% and diesel cars ranging from 15% to 27%.
4. Implications and Future Actions:
   • The switch from NEDC to WLTP has halved the real-world gap for conventional vehicles, but discrepancies still exist and need continuous monitoring.
   • The Commission plans to adjust the WLTP and utility factor for PHEVs to ensure emissions values remain representative.

‍