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PHEVs produce nearly 5x more planet-heating emissions than official figures show, according to a recent analysis.

Growing Gap In Official and Real-World CO2 Output

Data reveals that PHEVs emit only one-fifth lower CO₂ than traditional gas and diesel vehicles, based on analysis carried out by a advocacy group. This differs sharply with laboratory tests, which suggested a 75% decrease in pollution.

Analysts examined data from onboard fuel consumption meters of 800,000 vehicles registered in Europe between 2021 and 2023. The team discovered that actual CO₂ output from PHEVs in 2023 were nearly five times greater than lab estimates, up from three and a half times in 2021.

“Actual emissions are increasing, while lab-reported figures are decreasing,” said a senior researcher involved in the report. “That gap is growing and poses a significant problem. As a result, PHEVs pollute almost as much as gasoline vehicles.”

Key Factors Driving the Emissions Gap

Researchers attributed the majority of the difference to overestimates of the “electric driving share” – the percentage of miles driven in battery power relative to overall distance. The team determined that just a quarter of travel was completed in EV mode, while official assumptions suggested over four-fifths.

Additionally, when running in electric mode, pollution levels were significantly higher than official projections. This happened because electric motors were not strong sufficient to function independently, resulting to combustion motors burning fossil fuels for nearly a third of the travel completed in EV mode.

Policy and Financial Consequences

According to calculations, the underestimation of PHEV emissions allowed four large automaker groups to avoid over €5bn in penalties between 2021 and 2023, by artificially simplifying adherence with EU average fleet CO₂ targets.

Furthermore, owners of PHEVs would pay approximately €500 extra per year in running costs than is assumed under laboratory conditions.

“The strong statements that automakers often promote about their PHEV vehicles are obviously way off the mark,” commented a automotive analyst. “Buyers are being duped into thinking that by purchasing a PHEV, they are helping the planet and saving money. In reality, PHEVs are only slightly better than standard petrol and diesel vehicles in terms of energy use, CO₂ production, and running expenses.”

Policy Debate and Industry Lobbying

Hybrid cars have recently been drawn back into political discussions as carmakers have lobbied the EU to weaken CO₂ targets. A planned ban on new internal combustion vehicles in 2035 has faced intense pressure from the car industry and resistance from EU countries with significant car manufacturing.

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

An external energy economics expert, who was not involved with the research, described the report a “very useful contribution” after a long period in which segments of the car industry claimed there was too little data to properly evaluate real-world emissions.

“The results show, without question, that the difference between lab and real-world PHEV energy use and CO₂ output is much, much greater than for gasoline or diesel cars,” they said. “All policy adjustments regarding PHEVs should be made with extreme care and in the light of this evidence.”