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Plug-in hybrid cars release almost five times more planet-heating emissions than lab-reported data show, as per a recent report.

Growing Discrepancy In Official and Actual Emissions

Statistics reveals that PHEVs emit just 19% lower CO₂ than conventional petrol and diesel vehicles, based on research conducted by a advocacy group. This contrasts significantly with laboratory tests, which assumed a 75% reduction in emissions.

Researchers studied 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 greater than official estimates, up from three and a half times in 2021.

“Actual emissions are rising, while official figures are decreasing,” stated a lead analyst involved in the study. “That gap is widening and poses a significant issue. As a result, PHEVs emit almost as much as gasoline vehicles.”

Primary Factors Behind the Emissions Gap

Analysts linked the majority of the gap to inflated estimates of the “electric driving share” – the ratio of miles driven in electric power relative to overall mileage. They found that just 27% of driving was done in EV mode, while lab assumptions suggested over four-fifths.

Even, when operating in electric mode, emission amounts were significantly higher than official estimates. This occurred because EV motors were insufficiently powerful sufficient to operate independently, leading to combustion motors burning gasoline for almost one-third of the travel covered in EV mode.

Policy and Economic Implications

According to calculations, the lowballing of PHEV CO2 output enabled several major carmaker companies to avoid over €5bn in penalties between 2021 and 2023, by falsely simplifying compliance with European Union average fleet CO₂ standards.

Furthermore, owners of PHEVs could spend about €500 extra annually in running costs than would be estimated under laboratory conditions.

“The bold claims that manufacturers like to make about their plug-in hybrid cars are obviously far from the mark,” commented a transport analyst. “Consumers are being misled into believing that by buying a PHEV, they are benefiting the environment and cutting costs. In reality, PHEVs are little better than regular petrol and diesel vehicles in terms of fuel use, CO₂ emissions, and running expenses.”

Policy Debate and Automotive Lobbying

Hybrid vehicles have recently been brought again into political debates as carmakers have lobbied the EU to weaken CO₂ targets. A planned ban on sales of new combustion engine cars in 2035 has faced heavy lobbying from the car industry and opposition from EU countries with large automotive industries.

Several senior politicians have proposed plug-in hybrids as a potential “compromise” solution to include in the legislation.

An external energy policy expert, who was unaffiliated with the research, called the analysis a “very useful addition” after a long period in which segments of the car sector argued there was too little information to properly evaluate real-world CO2 output.

“The results demonstrate, beyond any doubt, that the gap between lab and real-world PHEV fuel consumption and CO₂ output is significantly greater than for gasoline or diesel vehicles,” the expert said. “Any regulatory adjustments regarding PHEVs should be made with extreme caution and in the light of that evidence.”