Plug-in Hybrid electric Cars Pollute Almost as Much as Petrol Vehicles, Report Reveals

Plug-in hybrid electric vehicles produce almost five times more global warming emissions than lab-reported data show, as per a recent report.

Growing Discrepancy Between Official and Actual CO2 Output

Statistics shows that PHEVs release just one-fifth less CO₂ than conventional gas and diesel cars, based on research conducted by a non-profit organization. That contrasts sharply with laboratory estimates, which assumed a three-quarters decrease in emissions.

Analysts studied data from onboard energy use monitors of 800,000 cars registered in Europe from 2021 and 2023. The team found that real-world CO₂ output from PHEVs in 2023 were 4.9 times greater than official estimates, up from 3.5 times in 2021.

“Real-world CO2 output are increasing, while official figures are decreasing,” stated a lead researcher participating in the study. “That gap is growing and creates a serious issue. Consequently, PHEVs pollute almost as much as petrol vehicles.”

Primary Factors Driving the Discrepancy

Researchers attributed the majority of the gap to inflated estimates of the “electric driving share” – the percentage of miles driven in battery power compared to overall distance. They determined that only a quarter of driving was done in EV mode, whereas official assumptions assumed over four-fifths.

Even, when running in EV mode, pollution amounts were well above official projections. That occurred because electric motors were not strong enough to function independently, leading to engines using gasoline for almost a third of the distance completed in electric mode.

Policy and Financial Consequences

According to calculations, the lowballing of PHEV emissions enabled several large automaker groups to escape over €5bn in fines from 2021 and 2023, by falsely easing compliance with European Union fleet-average CO₂ standards.

Additionally, drivers of PHEVs could pay approximately €500 extra annually in running costs than is assumed under lab tests.

“The strong claims that automakers often promote about their PHEV cars are clearly way off the mark,” stated a transport analyst. “Buyers are being duped into believing that by buying a PHEV, they are helping the planet and saving costs. In reality, PHEVs are only slightly improved than regular petrol and diesel cars in terms of energy use, CO₂ production, and running costs.”

Political Discussion and Automotive Lobbying

Hybrid cars have lately been drawn again into policy discussions as automakers have lobbied the European Union to weaken CO₂ standards. A proposed ban on new combustion engine vehicles in 2035 has faced intense lobbying from the automotive sector and resistance from EU countries with large automotive manufacturing.

Several high-level officials have proposed plug-in hybrids as a potential “flexibility” option to introduce in the regulation.

One external energy economics specialist, who was not involved with the research, described the report a “very useful contribution” after years in which parts of the automotive sector claimed there was insufficient information to accurately evaluate actual emissions.

“The results show, without question, that the gap between official and real-world PHEV fuel consumption and CO₂ emissions is significantly larger than for petrol or diesel cars,” they stated. “Any policy adjustments regarding PHEVs should be made with utmost caution and in the light of this evidence.”