EU Plug-in Hybrids Emit Six Times Official Ratings as Industry Fights 2027 Rule Changes

Key points

• Real-world CO2 emissions for PHEVs registered in 2024 averaged 145 g/km, compared to an official rating of 24 g/km, a six-fold discrepancy.
• Actual emissions rose by 5% from 2023 to 2024, while official ratings dropped by 15%, widening the gap between tested and real-world performance.
• The discrepancy is driven by 'utility factors,' which overestimate electric driving; many owners rarely plug in, causing PHEVs to operate like conventional hybrids.
• PHEVs are currently only 14% cleaner than conventional gas cars at the tailpipe, down from a 17% advantage in 2023.
• Automakers are lobbying the EU to cancel a 2027 correction to utility factors to maintain favorable emissions ratings and avoid billions in fines.

Background

This issue follows a decade of concerns regarding the gap between laboratory tests and real-world emissions, similar to the Dieselgate scandal. Previous coverage noted that while some manufacturers, like Lexus, are increasing battery sizes in hybrid models to improve efficiency, the broader industry has relied on PHEVs as a transitional technology. The current debate centers on whether regulatory adjustments will force a faster shift to battery electric vehicles or allow continued reliance on internal combustion engines with small batteries.

How outlets are covering it

Transport & Environment (T&E) argues that PHEVs are a 'greenwashing stunt' and that delaying utility factor corrections harms Europe's competitiveness against Chinese EV manufacturers. T&E cites data showing that accurate ratings would prevent automakers from avoiding billions in fines. Conversely, the European Automobile Manufacturers' Association (ACEA) and powertrain supplier Horse oppose the 2027 changes, arguing that tighter utility factors would harm the industry and make PHEVs less appealing to buyers. While T&E emphasizes environmental and consumer costs, industry groups focus on market viability and fleet compliance targets. All sources agree that the gap between official and real-world emissions is widening, but they differ on the urgency and method of regulatory intervention.

Why it matters

The accuracy of emissions ratings directly impacts consumer choices, fleet compliance costs, and the pace of the transition to electric vehicles. If official ratings remain disconnected from reality, automakers can continue selling polluting vehicles while claiming environmental progress, potentially delaying the adoption of fully electric technology and increasing reliance on fossil fuels.

What to watch

The EU Council is scheduled to debate the utility factor issue on October 12, 2026, followed by a parliamentary vote in November. The outcome will determine whether the 2027 correction to utility factors proceeds, which would make PHEV emissions ratings more realistic and potentially reduce their market appeal. T&E is urging lawmakers to reject industry demands to cancel the correction, while automakers continue to lobby for weaker standards.