🔗 Share this article

Plug-in hybrid cars emit almost five times more planet-heating pollution than official data show, as per a new report.

Growing Gap In Official and Actual CO2 Output

Data shows that PHEVs emit just 19% lower CO₂ than traditional petrol and diesel vehicles, according to research conducted by a advocacy organization. That differs sharply with lab estimates, which suggested a three-quarters decrease in pollution.

Researchers examined data from onboard energy use meters of eight hundred thousand vehicles registered in Europe between 2021 and 2023. They discovered that real-world CO₂ emissions from PHEVs in 2023 were 4.9 times higher than official figures, up from three and a half times in 2021.

“Real-world emissions are increasing, while official figures are decreasing,” said a lead analyst participating in the study. “This gap is widening and creates a serious issue. As a result, PHEVs pollute almost as much as petrol cars.”

Primary Reasons Behind the Discrepancy

Researchers attributed the majority of the gap to overestimates of the “electric driving share” – the ratio of miles travelled in battery power relative to total mileage. They determined that only 27% of driving was completed in electric mode, whereas lab estimates suggested over four-fifths.

Additionally, when operating in electric mode, pollution amounts were well above lab estimates. This occurred because electric motors were not strong sufficient to operate independently, leading to engines using gasoline for almost one-third of the distance completed in electric mode.

Policy and Economic Implications

According to estimates, the underestimation of PHEV emissions enabled several major carmaker groups to avoid more than €5bn in penalties from 2021 and 2023, by artificially simplifying adherence with European Union average fleet CO₂ targets.

Furthermore, owners of PHEVs would spend about €500 extra per year in operating costs than would be assumed under lab conditions.

“The strong statements that automakers often promote about their plug-in hybrid cars are clearly way off the truth,” commented a transport expert. “Buyers are being misled into thinking that by purchasing a PHEV, they are benefiting the planet and cutting costs. In reality, PHEVs are little better than regular gas and diesel cars in terms of fuel consumption, CO₂ emissions, and running costs.”

Policy Discussion and Automotive Lobbying

Hybrid cars have lately been drawn again into political debates as carmakers have lobbied the European Union to weaken CO₂ standards. A planned prohibition on sales of new internal combustion cars in 2035 has faced intense lobbying from the car industry and opposition from member states with significant car industries.

Several high-level officials have suggested plug-in hybrids as a potential “flexibility” option to include in the legislation.

One external energy policy expert, who was unaffiliated with the research, described the report a “very useful addition” after years in which parts of the automotive sector argued there was too little data to accurately evaluate real-world emissions.

“These findings demonstrate, beyond any doubt, that the difference in official and actual PHEV energy use and CO₂ output is significantly larger than for gasoline or conventional vehicles,” the expert stated. “Any regulatory changes regarding PHEVs should be implemented with utmost caution and in the light of this evidence.”