🔗 Share this article

Plug-in hybrid electric vehicles emit almost five times greater global warming emissions than official figures show, according to a recent analysis.

Widening Gap Between Official and Actual CO2 Output

Data reveals that PHEVs release just one-fifth less CO₂ than traditional petrol and diesel cars, based on research conducted by a non-profit organization. This contrasts significantly with lab tests, which suggested a three-quarters reduction in pollution.

Researchers examined data from onboard energy use monitors of eight hundred thousand cars registered in the EU from 2021 and 2023. They discovered that actual CO₂ output from PHEVs in 2023 were nearly five times higher than lab estimates, increased from three and a half times in 2021.

“Actual CO2 output are increasing, while lab-reported emissions are decreasing,” stated a senior analyst involved in the report. “That discrepancy is growing and creates a serious issue. As a result, PHEVs emit nearly as heavily as petrol vehicles.”

Key Reasons Driving the Emissions Gap

Analysts linked the majority of the gap to overestimates of the “utility factor” – the ratio of miles travelled in electric mode compared to overall mileage. The team found that just 27% of driving was completed in EV mode, while lab estimates suggested over four-fifths.

Additionally, when operating in EV mode, emission levels were well above lab projections. That occurred because EV motors were insufficiently powerful sufficient to operate alone, resulting to combustion motors using fossil fuels for almost a third of the travel completed in electric mode.

Regulatory and Economic Consequences

Based on estimates, the lowballing of PHEV CO2 output allowed several major automaker groups to avoid over €5bn in fines from 2021 and 2023, by falsely simplifying compliance with European Union fleet-average CO₂ standards.

Additionally, drivers of PHEVs could pay approximately €500 extra per year in running expenses than is assumed under laboratory conditions.

“The strong statements that automakers often promote about their PHEV cars are clearly way off the mark,” commented a transport expert. “Consumers are being misled into thinking that by purchasing a PHEV, they are benefiting the planet and saving costs. Actually, PHEVs are only slightly better than regular gas and diesel vehicles in terms of fuel use, CO₂ emissions, and operating expenses.”

Policy Debate and Automotive Lobbying

Hybrid vehicles have lately been drawn back into political discussions as carmakers have pressed the EU to weaken CO₂ standards. A proposed prohibition on new internal combustion cars in 2035 has faced intense lobbying from the car industry and opposition from member states with large car industries.

Some senior politicians have proposed plug-in hybrids as a potential “compromise” option to include in the regulation.

An external energy economics specialist, who was not involved with the study, called the analysis a “highly valuable contribution” after a long period in which parts of the automotive sector claimed there was too little information to accurately assess real-world CO2 output.

“The results show, beyond any doubt, that the difference between official and real-world PHEV energy use and CO₂ emissions is much, much greater than for gasoline or conventional vehicles,” they stated. “Any regulatory changes regarding PHEVs should be made with utmost care and in the light of this evidence.”