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

Plug-in hybrid cars release almost five times more planet-heating emissions than official figures show, according to a new analysis.

Growing Discrepancy Between Official and Actual CO2 Output

Statistics shows that PHEVs release only 19% less CO₂ than traditional gas and diesel cars, based on analysis conducted by a advocacy organization. This differs sharply with laboratory estimates, which suggested a three-quarters decrease in emissions.

Researchers studied data from onboard energy use meters of 800,000 cars registered in the EU from 2021 and 2023. The team found that actual CO₂ output from PHEVs in 2023 were nearly five times greater than lab figures, increased from 3.5 times in 2021.

“Real-world emissions are increasing, while lab-reported emissions are decreasing,” stated a senior analyst involved in the report. “That discrepancy is growing and poses a significant issue. Consequently, PHEVs pollute almost as much as gasoline cars.”

Primary Reasons Behind the Discrepancy

Analysts linked the majority of the gap to inflated estimates of the “electric driving share” – the ratio of miles driven in battery mode compared to overall distance. The team found that only 27% of travel was done in electric mode, whereas official estimates assumed over four-fifths.

Additionally, when operating in electric mode, emission levels were well above lab estimates. This happened because electric motors were insufficiently powerful sufficient to function alone, resulting to engines using gasoline for nearly one-third of the travel completed in EV mode.

Regulatory and Economic Consequences

According to calculations, the underestimation of PHEV emissions allowed several large automaker groups to avoid more than €5bn in penalties between 2021 and 2023, by falsely easing compliance with EU fleet-average CO₂ targets.

Furthermore, owners of PHEVs could pay about €500 extra annually in running costs than would be assumed under lab tests.

“The strong claims that manufacturers like to make about their plug-in hybrid vehicles are obviously way off the truth,” commented a automotive expert. “Consumers are being duped into believing that by purchasing a PHEV, they are benefiting the planet and saving costs. Actually, PHEVs are little better than standard petrol and diesel cars in terms of energy consumption, CO₂ emissions, and running expenses.”

Policy Debate and Industry Lobbying

Hybrid cars have lately been drawn again into policy discussions as carmakers have lobbied the EU to relax CO₂ targets. A proposed ban on new combustion engine vehicles in 2035 has faced intense pressure from the car industry and resistance from EU countries with large automotive manufacturing.

Several senior officials have suggested PHEVs as a potential “compromise” solution to introduce in the legislation.

One independent energy policy expert, who was unaffiliated with the study, called the report a “very useful contribution” after years in which segments of the automotive sector claimed there was too little information to accurately assess real-world CO2 output.

“These findings demonstrate, beyond any doubt, that the gap in lab and real-world PHEV energy use and CO₂ emissions is much, much larger than for gasoline or diesel cars,” they said. “Any regulatory changes concerning PHEVs should be implemented with utmost caution and considering that evidence.”