Plug-in Hybrid electric Vehicles Emit Almost as Much as Petrol Cars, Report Finds

PHEVs release almost 5x more planet-heating pollution than lab-reported data show, as per a recent analysis.

Growing Gap Between Lab and Actual Emissions

Statistics reveals that PHEVs emit just one-fifth less CO₂ than conventional petrol and diesel vehicles, based on research conducted by a non-profit organization. This contrasts significantly with lab estimates, which suggested a 75% decrease in pollution.

Researchers examined data from onboard energy use meters of eight hundred thousand cars registered in Europe from 2021 and 2023. The team discovered that real-world CO₂ output from PHEVs in 2023 were 4.9 times greater than lab figures, up from three and a half times in 2021.

“Actual emissions are increasing, while official figures are falling,” said a senior researcher involved in the report. “That discrepancy is growing and creates a significant issue. As a result, PHEVs pollute nearly as heavily as petrol vehicles.”

Key Reasons Driving the Discrepancy

Researchers linked the majority of the difference to overestimates of the “electric driving share” – the percentage of kilometers travelled in electric mode compared to total distance. They found that only 27% of driving was done in electric mode, while official estimates assumed over four-fifths.

Additionally, when running in electric mode, pollution levels were well above lab projections. That happened because electric motors were insufficiently powerful sufficient to operate alone, leading to combustion motors burning gasoline for almost one-third of the travel covered in electric mode.

Policy and Economic Implications

Based on estimates, the lowballing of PHEV emissions allowed several large carmaker groups to escape more than €5bn in fines between 2021 and 2023, by artificially simplifying adherence with European Union fleet-average CO₂ targets.

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

“The bold claims that automakers like to make about their PHEV cars are obviously far from the mark,” stated a automotive expert. “Consumers are being misled into thinking that by buying a PHEV, they are helping the planet and saving money. Actually, PHEVs are little better than standard petrol and diesel vehicles in terms of fuel use, CO₂ production, and operating costs.”

Policy Debate and Industry Lobbying

Hybrid cars have lately been drawn again into policy debates as automakers have pressed the European Union to relax CO₂ targets. A proposed ban on sales of new combustion engine vehicles in 2035 has faced intense pressure from the automotive sector and resistance from EU countries with large car industries.

Some high-level politicians have suggested PHEVs as a potential “compromise” solution to include in the legislation.

One external energy policy expert, who was not involved with the study, described the analysis a “highly valuable contribution” after a long period in which parts of the automotive sector argued there was insufficient data to properly assess actual CO2 output.

“These findings show, beyond any doubt, that the difference in lab and actual PHEV energy use and CO₂ output is significantly larger than for gasoline or conventional vehicles,” they said. “Any policy adjustments regarding PHEVs should be made with utmost care and considering this data.”