Plug-in Hybrid Vehicles Pollute Almost as Much as Petrol Cars, Report Reveals

Plug-in hybrid electric vehicles release almost 5x more planet-heating emissions than lab-reported figures show, as per a new analysis.

Widening Discrepancy Between Lab and Real-World Emissions

Statistics reveals that PHEVs emit just 19% lower CO₂ than traditional gas and diesel vehicles, according to analysis conducted by a advocacy organization. This contrasts sharply with laboratory estimates, which assumed a 75% reduction in emissions.

Researchers examined information from in-vehicle fuel consumption meters of eight hundred thousand vehicles registered in Europe from 2021 and 2023. They found that real-world CO₂ output from PHEVs in 2023 were nearly five times higher than official estimates, increased from three and a half times in 2021.

“Actual CO2 output are increasing, while lab-reported figures are decreasing,” said a lead analyst involved in the study. “That gap is growing and creates a significant issue. Consequently, PHEVs emit almost as much as gasoline vehicles.”

Key Factors Behind the Discrepancy

Analysts attributed most of the difference to overestimates of the “electric driving share” – the ratio of kilometers travelled in battery mode compared to total mileage. They determined that only a quarter of travel was completed in electric mode, whereas official assumptions suggested 84%.

Additionally, when running in EV mode, emission levels were significantly higher than lab estimates. That happened because electric motors were not strong enough to operate alone, resulting to combustion motors using fossil fuels for nearly a third of the distance covered in EV mode.

Regulatory and Economic Consequences

According to estimates, the lowballing of PHEV emissions enabled four large carmaker companies to avoid more than €5bn in fines from 2021 and 2023, by artificially easing adherence with European Union average fleet CO₂ targets.

Furthermore, owners of PHEVs would spend about €500 extra per year in running expenses than is estimated under lab tests.

“The strong statements that automakers like to make about their PHEV vehicles are clearly far from the mark,” stated a transport analyst. “Consumers are being misled into believing that by purchasing a PHEV, they are helping the planet and saving costs. Actually, PHEVs are little better than regular petrol and diesel vehicles in terms of energy use, CO₂ production, and operating costs.”

Political Debate and Industry Pressure

Hybrid cars have recently been brought again into political debates as carmakers have lobbied the EU to relax CO₂ targets. A planned prohibition on new internal combustion vehicles in 2035 has faced intense pressure from the car sector and resistance from member states with large car manufacturing.

Some high-level politicians have proposed PHEVs as a potential “flexibility” solution to introduce in the regulation.

One external energy policy expert, who was unaffiliated with the study, called the report a “highly valuable contribution” after years in which segments of the car industry argued there was insufficient information to accurately assess actual emissions.

“The results show, without question, that the gap in lab and real-world PHEV fuel consumption and CO₂ output is significantly larger than for gasoline or diesel cars,” the expert said. “Any policy adjustments concerning PHEVs should be made with utmost care and in the light of that data.”