🔗 Share this article

Plug-in hybrid electric vehicles produce almost five times greater global warming emissions than official data indicate, according to a recent analysis.

Widening Discrepancy Between Lab and Actual CO2 Output

Data reveals that PHEVs release only one-fifth less CO₂ than conventional petrol and diesel vehicles, according to analysis conducted by a advocacy group. That differs significantly with laboratory estimates, which assumed a 75% decrease in pollution.

Researchers examined information from in-vehicle fuel consumption monitors of 800,000 vehicles sold in the EU between 2021 and 2023. They found that real-world CO₂ emissions from PHEVs in 2023 were nearly five times higher than lab estimates, up from three and a half times in 2021.

“Actual emissions are increasing, while official emissions are decreasing,” said a lead analyst participating in the report. “This gap is growing and creates a serious problem. Consequently, PHEVs emit almost as heavily as petrol cars.”

Key Factors Behind the Discrepancy

Researchers attributed most of the difference to overestimates of the “electric driving share” – the ratio of kilometers driven in battery mode compared to total mileage. They determined that only a quarter of driving was done in electric mode, while lab assumptions suggested over four-fifths.

Additionally, when operating in electric mode, emission levels were well above official projections. That occurred because EV motors were not strong enough to function alone, resulting to combustion motors burning gasoline for almost a third of the distance completed in EV mode.

Regulatory and Financial Consequences

According to estimates, the lowballing of PHEV CO2 output allowed four major carmaker companies to escape more than €5bn in fines from 2021 and 2023, by falsely easing compliance with European Union fleet-average CO₂ standards.

Additionally, owners of PHEVs could spend approximately €500 extra per year in operating expenses than is assumed under laboratory tests.

“The bold claims that manufacturers like to make about their plug-in hybrid cars are clearly way off the mark,” stated a transport expert. “Buyers are being misled into thinking that by buying a PHEV, they are helping the planet and saving money. In reality, PHEVs are only slightly improved than standard gas and diesel cars in terms of energy consumption, CO₂ emissions, and running expenses.”

Political Discussion and Industry Lobbying

Plug-in hybrid cars have lately been brought again into policy discussions as automakers have pressed the European Union to weaken CO₂ targets. A planned ban on new internal combustion vehicles in 2035 has faced heavy pressure from the automotive sector and opposition from EU countries with large car industries.

Some senior officials have suggested plug-in hybrids as a potential “compromise” solution to include in the legislation.

An external energy policy expert, who was not involved with the research, called the analysis a “very useful contribution” after years in which parts of the car sector claimed there was insufficient data to properly assess real-world CO2 output.

“These findings show, beyond any doubt, that the gap between official and real-world PHEV energy use and CO₂ output is much, much greater than for gasoline or diesel cars,” they said. “All regulatory adjustments concerning PHEVs should be implemented with utmost caution and in the light of this evidence.”