Plug-in Hybrid Cars Pollute Almost as Heavily as Gasoline Cars, Study Finds

Plug-in hybrid electric vehicles release almost five times more planet-heating emissions than official data show, as per a new report.

Widening Gap Between Lab and Actual Emissions

Statistics shows that PHEVs emit only 19% lower CO₂ than conventional gas and diesel cars, based on analysis conducted by a advocacy group. This differs significantly with laboratory tests, which assumed a 75% decrease in emissions.

Researchers studied information from onboard fuel consumption meters of eight hundred thousand cars registered in Europe between 2021 and 2023. The team found that actual CO₂ output from PHEVs in 2023 were 4.9 times higher than official estimates, increased from three and a half times in 2021.

“Actual CO2 output are rising, while official emissions are falling,” stated a lead analyst participating in the study. “That discrepancy is widening and poses a significant problem. Consequently, PHEVs pollute almost as heavily as gasoline vehicles.”

Primary Reasons Behind the Discrepancy

Researchers linked the majority of the gap to inflated estimates of the “electric driving share” – the percentage of miles driven in battery power relative to overall mileage. The team found that only a quarter of travel was done in EV mode, whereas official assumptions suggested over four-fifths.

Even, when operating in EV mode, pollution amounts were well above lab projections. This occurred because electric motors were not strong sufficient to operate alone, leading to combustion motors burning fossil fuels for almost one-third of the travel completed in EV mode.

Regulatory and Financial Consequences

Based on calculations, the underestimation of PHEV emissions allowed several major carmaker groups to avoid more than €5bn in fines between 2021 and 2023, by falsely simplifying compliance with European Union average fleet CO₂ targets.

Furthermore, owners of PHEVs would pay approximately €500 more annually in running costs than is assumed under laboratory tests.

“The bold claims that automakers like to make about their plug-in hybrid cars are clearly way off the truth,” stated a automotive expert. “Consumers are being misled into thinking that by buying a PHEV, they are helping the planet and saving costs. In reality, PHEVs are only slightly better than regular gas and diesel cars in terms of energy consumption, CO₂ production, and operating expenses.”

Political Debate and Industry Pressure

Hybrid vehicles have recently been brought back into political discussions as carmakers have lobbied the European Union to relax CO₂ standards. A proposed ban on sales of new internal combustion cars in 2035 has faced heavy lobbying from the car industry and resistance from member states with large car industries.

Several senior politicians have suggested plug-in hybrids as a potential “compromise” option to include in the regulation.

An external energy economics expert, who was not involved with the research, described the analysis a “very useful contribution” after a long period in which segments of the car sector claimed there was insufficient data to accurately evaluate real-world emissions.

“The results demonstrate, without question, that the gap between lab and real-world PHEV energy use and CO₂ emissions is much, much greater than for gasoline or conventional cars,” they said. “Any policy adjustments regarding PHEVs should be made with utmost caution and considering this evidence.”