Plug-in hybrid vehicles (PHEVs) are not as environmentally friendly as previously claimed, according to recent EU data.

• Real-world emissions from PHEVs average 135 g CO₂/km, only 19% less than conventional petrol and diesel cars which average 166 g CO₂/km.
• Official WLTP tests significantly underestimate emissions; PHEVs often run on the combustion engine, even in electric mode, increasing real fuel consumption.
• In electric-only mode, PHEVs still burn around 3 liters of petrol per 100 km, resulting in emissions of 68 g CO₂/km—over eight times higher than manufacturers’ claims.
• Hidden fuel consumption costs drivers approximately 500 euros per year more than official manufacturer data suggests.
• PHEVs are among the most expensive on the market; average price in 2025 in Germany, France and the UK is 55,700 euros, about 15,000 euros higher than average battery-only electric cars.
• Increasing electric range through larger batteries does not reduce emissions; heavier vehicles consume more fuel and energy overall.
• PHEVs with electric ranges above 75 km emit more CO₂ on average than those with ranges of 45–75 km.
• The biggest discrepancies are noted for Mercedes-Benz plug-in hybrids; in 2023, their real emissions exceeded official figures by an average of 494%, with the GLE-Class over by 611%.
• Automotive industry is lobbying to have PHEVs recognized as low-emission beyond 2035, despite new EU regulations that require the transition to zero-emission vehicles.
• Weakening EU regulations could undermine the development and adoption of truly zero-emission technologies.
• According to Transport & Environment, plug-in hybrids are “one of the biggest myths in motoring,” often emitting almost as much as combustion-engine cars and much more than test results indicate.
• EEA and T&E data casts doubt on PHEVs as effective solutions for transportation decarbonization; their environmental benefits are increasingly questioned.