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

Plug-in hybrid electric vehicles release almost five times more planet-heating emissions than official figures indicate, as per a new analysis.

Widening Discrepancy Between Lab and Actual Emissions

Statistics reveals that PHEVs release just 19% lower CO₂ than traditional gas and diesel vehicles, based on analysis conducted by a non-profit organization. That contrasts significantly with laboratory estimates, which assumed a 75% reduction in emissions.

Analysts examined information from in-vehicle energy use monitors of 800,000 vehicles registered in the EU between 2021 and 2023. They discovered that actual CO₂ emissions from PHEVs in 2023 were 4.9 times higher than official estimates, increased from three and a half times in 2021.

“Actual CO2 output are increasing, while official figures are decreasing,” stated a lead analyst participating in the report. “That gap is growing and poses a serious problem. As a result, PHEVs emit almost as much as petrol cars.”

Primary Factors Driving the Emissions Gap

Researchers attributed the majority of the difference to overestimates of the “electric driving share” – the ratio of kilometers travelled in battery power compared to overall mileage. The team found that just 27% of travel was done in electric mode, while lab estimates assumed over four-fifths.

Even, when running in EV mode, emission amounts were significantly higher than official projections. This happened because EV motors were insufficiently powerful enough to operate alone, resulting to combustion motors using gasoline for nearly a third of the travel covered in EV mode.

Regulatory and Financial Implications

Based on estimates, the underestimation of PHEV CO2 output allowed four large automaker groups to escape over €5bn in penalties from 2021 and 2023, by artificially easing compliance with European Union average fleet CO₂ targets.

Additionally, owners of PHEVs could pay approximately €500 extra annually in running expenses than is estimated under lab tests.

“The strong claims that manufacturers often promote about their PHEV vehicles are obviously far from the mark,” commented a transport expert. “Consumers are being duped into believing that by buying a PHEV, they are helping the planet and cutting costs. In reality, PHEVs are little improved than regular gas and diesel cars in terms of fuel use, CO₂ production, and operating expenses.”

Political Discussion and Automotive Lobbying

Hybrid cars have lately been brought back into policy debates as automakers have pressed the EU to weaken CO₂ targets. A planned prohibition on sales of new combustion engine vehicles in 2035 has faced intense lobbying from the automotive sector and opposition from member states with significant automotive manufacturing.

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

An independent energy economics specialist, who was not involved with the study, called the report a “highly valuable contribution” after a long period in which parts of the automotive industry argued there was too little information to properly evaluate actual emissions.

“These findings show, without question, that the gap in lab and real-world PHEV energy use and CO₂ output is much, much larger than for petrol or diesel cars,” they stated. “All policy adjustments concerning PHEVs should be implemented with extreme care and in the light of that data.”