A new analysis by Transport & Environment (T&E) reveals that plug-in hybrid (PHEV) vehicles registered in 2024 emitted six times more CO2 in real-world conditions than official figures indicated. This gap has widened since 2023, when the discrepancy factor was approximately five.
The report highlights that the real-world fuel costs for a 2024 PHEV model average €680 higher annually than official consumption data suggests. Furthermore, while official tests claimed an 83 per cent reduction in emissions compared to internal combustion vehicles, the actual reduction is only 14 per cent.
The discrepancy stems from frequent engine usage during electric-mode driving, which accounts for one-third of battery-mode mileage. The International Council on Clean Transportation (ICCT) confirmed similar findings, citing lower-than-expected electric range and vehicle weight as key factors.
In response to EU regulatory adjustments, manufacturers have increased battery sizes and electric ranges. For instance, the Volkswagen Tiguan saw its electric range rise from 55 to 119 km. T&E suggests that further technical improvements could keep PHEV emissions below the 50 g CO2/km threshold.
T&E warns that freezing the current utility factor at 2025/26 levels would still underestimate real-world emissions by 56 per cent. This impacts manufacturer fleet CO2 balances, potentially altering the number of pure electric vehicles required to meet European targets.
