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PHEVs emit nearly five times more planet-heating emissions than lab-reported figures indicate, according to a new analysis.

Widening Discrepancy In Official and Actual Emissions

Statistics shows that PHEVs release only 19% less CO₂ than traditional gas and diesel cars, based on research carried out by a advocacy organization. This contrasts significantly with lab estimates, which assumed a three-quarters decrease in emissions.

Analysts studied information from onboard fuel consumption 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 4.9 times greater than lab estimates, up from three and a half times in 2021.

“Actual CO2 output are rising, while official emissions are decreasing,” stated a lead analyst involved in the study. “This gap is growing and poses a significant issue. Consequently, PHEVs pollute almost as heavily as gasoline cars.”

Primary Reasons Driving the Discrepancy

Researchers linked most of the gap to inflated estimates of the “electric driving share” – the ratio of kilometers travelled in electric power relative to overall mileage. The team determined that only a quarter of travel was completed in EV mode, whereas official assumptions suggested over four-fifths.

Additionally, when running in EV mode, pollution levels were well above lab estimates. That happened because EV motors were not strong sufficient to operate independently, resulting to combustion motors burning gasoline for almost one-third of the travel completed in electric mode.

Regulatory and Economic Implications

Based on calculations, the lowballing of PHEV emissions enabled four major automaker companies to escape over €5bn in fines from 2021 and 2023, by falsely easing adherence with EU fleet-average CO₂ standards.

Additionally, owners of PHEVs would pay about €500 extra per year in running costs than would be estimated under lab conditions.

“The strong claims that manufacturers like to make about their PHEV cars are obviously far from the truth,” stated a automotive analyst. “Consumers are being misled into thinking that by purchasing a PHEV, they are helping the planet and cutting costs. In reality, PHEVs are little better than standard petrol and diesel vehicles in terms of fuel use, CO₂ production, and running costs.”

Policy Discussion and Automotive Lobbying

Plug-in hybrid cars have recently been brought back into policy debates as automakers have pressed the European Union to weaken CO₂ standards. A proposed ban on new combustion engine cars in 2035 has faced heavy lobbying from the car industry and resistance from member states with significant car industries.

Some high-level politicians have suggested plug-in hybrids as a potential “compromise” solution to include in the regulation.

An independent energy policy specialist, who was not involved with the study, called the analysis a “highly valuable contribution” after years in which parts of the car sector claimed there was too little information to accurately assess actual emissions.

“These findings show, without question, that the difference between lab and actual PHEV energy use and CO₂ emissions is significantly larger than for gasoline or diesel cars,” they stated. “All policy adjustments concerning PHEVs should be implemented with extreme care and considering that evidence.”