Plug-in Hybrid electric Cars Emit Almost as Heavily as Gasoline Cars, Report Finds

Plug-in hybrid electric vehicles produce almost 5x more planet-heating emissions than official data show, according to a recent report.

Growing Gap Between Lab and Actual CO2 Output

Statistics shows that PHEVs emit just 19% less CO₂ than traditional petrol and diesel cars, based on analysis conducted by a non-profit organization. This contrasts sharply with lab estimates, which suggested a three-quarters decrease in emissions.

Analysts studied data from in-vehicle fuel consumption meters of eight hundred thousand cars registered in the EU from 2021 and 2023. The team found that actual CO₂ emissions from PHEVs in 2023 were 4.9 times greater than lab figures, increased from 3.5 times in 2021.

“Actual CO2 output are rising, while lab-reported figures are decreasing,” stated a lead analyst participating in the report. “This discrepancy is growing and poses a significant problem. Consequently, PHEVs emit almost as much as petrol vehicles.”

Primary Reasons Behind the Discrepancy

Analysts linked the majority of the difference to overestimates of the “utility factor” – the ratio of miles travelled in battery power relative to overall distance. They found that only a quarter of travel was completed in electric mode, while official assumptions assumed 84%.

Additionally, when running in electric mode, pollution levels were significantly higher than lab projections. This happened because electric motors were not strong enough to operate independently, leading to combustion motors burning gasoline for nearly one-third of the travel covered in electric mode.

Regulatory and Economic Implications

Based on estimates, the lowballing of PHEV emissions enabled several large automaker groups to escape over €5bn in penalties from 2021 and 2023, by falsely simplifying adherence with European Union average fleet CO₂ targets.

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

“The bold statements that automakers like to make about their plug-in hybrid cars are obviously way off the truth,” commented a transport expert. “Buyers are being misled into believing that by purchasing a PHEV, they are benefiting the environment and saving money. Actually, PHEVs are little improved than regular petrol and diesel cars in terms of fuel consumption, CO₂ emissions, and operating costs.”

Political Discussion and Automotive Pressure

Plug-in hybrid cars have lately been drawn back into political debates as automakers have pressed the European Union to weaken CO₂ targets. A planned ban on sales of new combustion engine cars in 2035 has faced intense lobbying from the car sector and resistance from member states with significant car industries.

Some high-level officials have suggested plug-in hybrids as a possible “compromise” option to introduce in the legislation.

One independent energy economics expert, who was not involved with the research, called the analysis a “very useful contribution” after years in which segments of the car sector argued there was insufficient data to accurately evaluate real-world CO2 output.

“The results show, beyond any doubt, that the difference in lab and actual PHEV energy use and CO₂ output is significantly greater than for petrol or diesel vehicles,” they said. “All regulatory changes concerning PHEVs should be implemented with extreme caution and in the light of this data.”