🔗 Share this article

PHEVs release almost five times more global warming pollution than official data indicate, according to a recent report.

Growing Gap In Lab and Actual Emissions

Statistics shows that PHEVs emit just one-fifth lower CO₂ than traditional petrol and diesel vehicles, based on research conducted by a non-profit group. This differs sharply with laboratory tests, which assumed a three-quarters reduction in pollution.

Analysts studied information from onboard fuel consumption monitors of 800,000 vehicles sold in Europe from 2021 and 2023. They discovered that real-world CO₂ output from PHEVs in 2023 were 4.9 times greater than lab figures, up from 3.5 times in 2021.

“Actual emissions are increasing, while official figures are falling,” stated a lead analyst involved in the study. “This discrepancy is growing and poses a serious problem. Consequently, PHEVs emit nearly as much as petrol cars.”

Primary Reasons Driving the Discrepancy

Analysts linked most of the difference to inflated estimates of the “electric driving share” – the percentage of miles driven in electric power compared to overall mileage. They found that just 27% of driving was completed in EV mode, whereas official assumptions assumed over four-fifths.

Even, when running in electric mode, emission levels were well above lab estimates. That occurred because EV motors were insufficiently powerful sufficient to operate alone, leading to engines burning fossil fuels for nearly a third of the travel covered in electric mode.

Policy and Economic Consequences

According to estimates, the underestimation of PHEV emissions allowed several major automaker groups to avoid over €5bn in fines between 2021 and 2023, by artificially easing compliance with EU fleet-average CO₂ standards.

Furthermore, owners of PHEVs would spend about €500 more annually in running costs than would be assumed under laboratory conditions.

“The strong claims that manufacturers often promote about their plug-in hybrid vehicles are clearly way off the truth,” commented a transport analyst. “Consumers are being duped into thinking that by buying a PHEV, they are helping the environment and saving money. In reality, PHEVs are only slightly better than standard petrol and diesel cars in terms of energy consumption, CO₂ production, and operating expenses.”

Policy Debate and Automotive Lobbying

Hybrid vehicles have lately been drawn again into political debates as carmakers have lobbied the EU to weaken CO₂ targets. A planned prohibition on new internal combustion cars in 2035 has faced intense lobbying from the automotive sector and opposition from EU countries with significant car manufacturing.

Some high-level politicians have proposed PHEVs as a possible “compromise” solution to include in the regulation.

One independent energy economics expert, who was not involved with the study, described the analysis a “highly valuable addition” after a long period in which segments of the car sector argued there was insufficient data to properly evaluate actual CO2 output.

“These findings demonstrate, beyond any doubt, that the gap between lab and real-world PHEV energy use and CO₂ emissions is much, much greater than for gasoline or diesel cars,” the expert said. “All policy adjustments regarding PHEVs should be implemented with extreme caution and considering that data.”