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PHEVs emit nearly five times more planet-heating emissions than official data indicate, as per a new report.

Growing Gap In Official and Actual CO2 Output

Statistics shows that PHEVs emit only 19% less CO₂ than traditional gas and diesel cars, based on research conducted by a advocacy organization. That contrasts significantly with laboratory estimates, which assumed a three-quarters decrease in pollution.

Researchers examined data from onboard fuel consumption meters of eight hundred thousand vehicles registered in the EU between 2021 and 2023. The team discovered that actual CO₂ emissions from PHEVs in 2023 were nearly five times greater than lab figures, increased from 3.5 times in 2021.

“Real-world emissions are rising, while official emissions are decreasing,” stated a lead analyst involved in the report. “That discrepancy is widening and poses a serious problem. Consequently, PHEVs pollute nearly as heavily as gasoline vehicles.”

Primary Reasons Behind the Discrepancy

Analysts linked the majority of the difference to inflated estimates of the “electric driving share” – the percentage of kilometers driven in battery mode compared to overall mileage. The team found that only a quarter of travel was done in electric mode, whereas lab estimates assumed over four-fifths.

Even, when running in electric mode, pollution levels were significantly higher than lab projections. This happened because EV motors were insufficiently powerful sufficient to operate alone, leading to combustion motors using gasoline for nearly a third of the travel completed in EV mode.

Policy and Financial Consequences

According to estimates, the underestimation of PHEV emissions enabled four large carmaker companies to avoid more than €5bn in penalties from 2021 and 2023, by artificially simplifying compliance with EU fleet-average CO₂ targets.

Additionally, drivers of PHEVs could pay about €500 extra annually in operating costs than is estimated under lab conditions.

“The strong claims that manufacturers like to make about their PHEV cars are obviously far from the truth,” commented a transport expert. “Buyers are being duped into believing that by purchasing a PHEV, they are benefiting the environment and cutting money. In reality, PHEVs are little better than standard gas and diesel vehicles in terms of fuel consumption, CO₂ production, and running expenses.”

Political Debate and Industry Pressure

Plug-in hybrid vehicles have recently been brought back into policy debates as carmakers have lobbied the European Union to weaken CO₂ targets. A proposed prohibition on new internal combustion vehicles in 2035 has faced heavy lobbying from the car sector and opposition from EU countries with large automotive industries.

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

An independent energy economics specialist, who was unaffiliated with the study, called the analysis a “very useful contribution” after years in which segments of the automotive industry claimed there was too little information to accurately evaluate real-world emissions.

“The results show, without question, that the gap between lab and actual PHEV energy use and CO₂ output is much, much greater than for gasoline or diesel cars,” they stated. “All regulatory adjustments regarding PHEVs should be implemented with utmost caution and considering this evidence.”