🔗 Share this article

Plug-in hybrid electric vehicles release nearly five times greater global warming pollution than lab-reported data indicate, according to a new report.

Growing Gap In Lab and Real-World CO2 Output

Statistics reveals that PHEVs release only 19% less CO₂ than conventional petrol and diesel vehicles, according to analysis conducted by a non-profit group. That differs significantly with laboratory estimates, which suggested a 75% decrease in emissions.

Researchers examined information from onboard energy use meters of 800,000 cars registered in Europe from 2021 and 2023. The team discovered that real-world CO₂ output from PHEVs in 2023 were nearly five times greater than official figures, increased from three and a half times in 2021.

“Actual emissions are increasing, while official figures are falling,” stated a senior researcher involved in the study. “That discrepancy is growing and creates a serious issue. Consequently, PHEVs pollute nearly as heavily as gasoline cars.”

Key Factors Behind the Discrepancy

Researchers attributed the majority of the difference to inflated estimates of the “utility factor” – the percentage of miles travelled in electric power relative to total distance. They found that only 27% of travel was done in electric mode, whereas lab assumptions suggested over four-fifths.

Additionally, when running in EV mode, pollution amounts were well above official projections. That occurred because EV motors were not strong sufficient to operate independently, resulting to engines burning gasoline for nearly a third of the distance completed in EV mode.

Policy and Financial Consequences

Based on estimates, the underestimation of PHEV emissions allowed several large automaker companies to avoid more than €5bn in penalties between 2021 and 2023, by falsely easing compliance with EU average fleet CO₂ targets.

Additionally, owners of PHEVs would pay about €500 extra annually in operating costs than is assumed under laboratory conditions.

“The strong claims that automakers like to make about their plug-in hybrid vehicles are clearly far from the mark,” commented a transport analyst. “Buyers are being misled into believing that by buying a PHEV, they are helping the planet and saving costs. Actually, PHEVs are little improved than standard gas and diesel vehicles in terms of fuel use, CO₂ emissions, and operating expenses.”

Political Discussion and Industry Lobbying

Plug-in hybrid vehicles have recently been drawn back into political discussions as automakers have pressed the EU to relax CO₂ standards. A proposed prohibition on new combustion engine cars in 2035 has faced intense pressure from the automotive sector and resistance from member states with large automotive manufacturing.

Several senior politicians have suggested PHEVs as a possible “flexibility” solution to introduce in the regulation.

An independent energy policy specialist, who was not involved with the research, described the report a “highly valuable addition” after a long period in which parts of the automotive sector claimed there was insufficient data to accurately assess actual CO2 output.

“These findings show, without question, that the difference between lab and actual PHEV energy use and CO₂ output is significantly larger than for gasoline or conventional cars,” they said. “Any policy adjustments concerning PHEVs should be implemented with extreme caution and in the light of this evidence.”