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PHEVs emit almost 5x more planet-heating emissions than official data show, according to a recent report.

Growing Discrepancy In Official and Actual Emissions

Data reveals that PHEVs release just 19% less CO₂ than conventional petrol and diesel vehicles, according to research conducted by a non-profit group. This contrasts sharply with laboratory estimates, which assumed a 75% decrease in pollution.

Researchers studied information from in-vehicle fuel consumption meters of eight hundred thousand cars sold in the EU between 2021 and 2023. They found that actual CO₂ emissions from PHEVs in 2023 were 4.9 times higher than official estimates, up from three and a half times in 2021.

“Actual emissions are rising, while official figures are decreasing,” stated a senior researcher involved in the report. “This discrepancy is widening and creates a serious problem. Consequently, PHEVs pollute almost as much as gasoline vehicles.”

Key Factors Driving the Emissions Gap

Analysts linked the majority of the difference to overestimates of the “electric driving share” – the percentage of kilometers travelled in electric power compared to total distance. The team determined that only 27% of travel was done in EV mode, while lab assumptions assumed 84%.

Even, when operating in electric mode, pollution levels were well above lab estimates. This happened because EV motors were not strong sufficient to operate alone, leading to combustion motors burning fossil fuels for nearly a third of the distance completed in EV mode.

Policy and Financial Implications

According to estimates, the underestimation of PHEV CO2 output enabled several large automaker groups to avoid over €5bn in fines between 2021 and 2023, by artificially easing adherence with EU fleet-average CO₂ targets.

Additionally, owners of PHEVs would pay approximately €500 more annually in operating expenses than would be assumed under laboratory tests.

“The strong claims that automakers like to make about their plug-in hybrid cars are obviously way off the truth,” commented a automotive analyst. “Consumers are being duped into believing that by purchasing a PHEV, they are helping the planet and saving costs. Actually, PHEVs are little improved than standard gas and diesel cars in terms of energy consumption, CO₂ production, and running costs.”

Policy Debate and Automotive Pressure

Hybrid vehicles have recently been drawn back into political debates as automakers have lobbied the EU to relax CO₂ targets. A planned prohibition on sales of new combustion engine cars in 2035 has faced heavy lobbying from the automotive industry and resistance from member states with significant car manufacturing.

Several senior politicians have proposed PHEVs as a possible “flexibility” option to introduce in the regulation.

An external energy policy specialist, who was not involved with the study, described the report a “very useful contribution” after years in which segments of the car sector argued there was insufficient data to properly evaluate actual CO2 output.

“The results demonstrate, without question, that the difference in lab and real-world PHEV fuel consumption and CO₂ output is much, much greater than for gasoline or diesel cars,” they stated. “All policy changes regarding PHEVs should be implemented with utmost caution and considering this evidence.”