🔗 Share this article

Plug-in hybrid electric vehicles release almost 5x more global warming pollution than official figures show, according to a new report.

Growing Discrepancy Between Official and Actual Emissions

Statistics reveals that PHEVs release only 19% lower CO₂ than conventional petrol and diesel vehicles, based on research conducted by a non-profit group. That differs significantly with lab estimates, which suggested a 75% decrease in pollution.

Researchers examined information from onboard energy use meters of eight hundred thousand cars sold in Europe between 2021 and 2023. The team found that real-world CO₂ emissions from PHEVs in 2023 were nearly five times greater than lab figures, increased from 3.5 times in 2021.

“Actual emissions are rising, while lab-reported emissions are falling,” stated a senior researcher participating in the study. “That discrepancy is growing and creates a significant problem. Consequently, PHEVs emit almost as heavily as gasoline cars.”

Primary Reasons Behind the Discrepancy

Researchers attributed most of the gap to overestimates of the “electric driving share” – the ratio of kilometers driven in battery mode relative to total distance. They found that only a quarter of driving was done in EV mode, whereas official estimates assumed 84%.

Even, when operating in electric mode, pollution amounts were significantly higher than official estimates. This occurred because electric motors were not strong sufficient to operate alone, leading to combustion motors using gasoline for almost a third of the distance covered in EV mode.

Policy and Economic Implications

Based on calculations, the lowballing of PHEV CO2 output allowed four large carmaker companies to avoid more than €5bn in penalties from 2021 and 2023, by falsely simplifying compliance with European Union average fleet CO₂ targets.

Additionally, drivers of PHEVs could pay about €500 extra per year in running costs than would be assumed under laboratory conditions.

“The strong statements that manufacturers often promote about their PHEV vehicles are obviously way off the mark,” commented a transport expert. “Consumers are being misled into thinking that by purchasing a PHEV, they are helping the planet and saving money. Actually, PHEVs are only slightly better than standard petrol and diesel vehicles in terms of fuel consumption, CO₂ emissions, and running costs.”

Political Discussion and Automotive Pressure

Hybrid cars have recently been brought back into political debates as carmakers have pressed the EU to relax CO₂ targets. A proposed ban on sales of new combustion engine vehicles in 2035 has faced intense pressure from the car industry and resistance from member states with large automotive industries.

Some high-level officials have suggested plug-in hybrids as a possible “flexibility” solution to include in the regulation.

An external energy policy expert, who was unaffiliated with the research, called the analysis a “highly valuable addition” after a long period in which segments of the automotive sector claimed there was insufficient data to properly evaluate real-world CO2 output.

“The results show, beyond any doubt, that the gap in official and real-world PHEV fuel consumption and CO₂ emissions is much, much greater than for petrol or conventional cars,” they stated. “All policy changes concerning PHEVs should be implemented with extreme caution and in the light of this evidence.”