🔗 Share this article

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

Growing Discrepancy In Official and Actual Emissions

Statistics shows that PHEVs release only 19% lower CO₂ than traditional gas and diesel vehicles, according to research carried out by a advocacy organization. This differs significantly with laboratory estimates, which suggested a 75% decrease in emissions.

Researchers examined data from onboard energy use meters of eight hundred thousand vehicles registered in Europe between 2021 and 2023. They found that actual CO₂ emissions from PHEVs in 2023 were 4.9 times greater than lab figures, up from three and a half times in 2021.

“Real-world CO2 output are increasing, while official figures are decreasing,” said a lead researcher participating in the report. “This gap is growing and creates a significant issue. As a result, PHEVs emit nearly as much as petrol vehicles.”

Key Reasons Behind the Discrepancy

Researchers attributed most of the gap to inflated estimates of the “electric driving share” – the ratio of miles travelled in electric power relative to total mileage. They found that only 27% of driving was completed in EV mode, whereas official estimates assumed 84%.

Additionally, when running in electric mode, pollution levels were well above official estimates. That occurred because EV motors were not strong sufficient to operate independently, leading to engines using gasoline for almost a third of the distance completed in EV mode.

Regulatory and Financial Implications

According to estimates, the lowballing of PHEV emissions enabled several large carmaker companies to avoid over €5bn in penalties from 2021 and 2023, by falsely easing adherence with EU fleet-average CO₂ targets.

Additionally, owners of PHEVs could spend approximately €500 more per year in running costs than would be assumed under laboratory conditions.

“The strong claims that automakers like to make about their PHEV cars are obviously far from the truth,” commented a transport expert. “Buyers are being duped into thinking that by buying a PHEV, they are benefiting the planet and saving costs. In reality, PHEVs are little better than standard gas and diesel vehicles in terms of energy consumption, CO₂ production, and operating expenses.”

Political Discussion and Industry Pressure

Hybrid vehicles have recently been brought back into political debates as automakers have pressed the European Union to weaken CO₂ standards. A planned prohibition on new combustion engine vehicles in 2035 has faced intense pressure from the car industry and resistance from member states with significant automotive manufacturing.

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

An independent energy economics specialist, who was unaffiliated with the research, called the report a “very useful contribution” after years in which segments of the car industry argued there was too little data to properly evaluate real-world emissions.

“These findings demonstrate, without question, that the gap between official and real-world PHEV fuel consumption and CO₂ emissions is much, much larger than for gasoline or conventional cars,” they stated. “All policy changes regarding PHEVs should be made with utmost care and considering that data.”