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Plug-in hybrid cars produce nearly five times more planet-heating pollution than lab-reported data show, as per a recent analysis.

Widening Discrepancy Between Official and Actual CO2 Output

Statistics reveals that PHEVs emit only one-fifth lower CO₂ than traditional petrol and diesel cars, according to analysis carried out by a advocacy organization. This differs sharply with laboratory estimates, which suggested a 75% reduction in emissions.

Analysts examined data from in-vehicle energy use monitors of 800,000 vehicles registered in the EU between 2021 and 2023. They discovered that real-world CO₂ output from PHEVs in 2023 were nearly five times greater than lab estimates, up from 3.5 times in 2021.

“Actual emissions are rising, while official figures are decreasing,” said a senior analyst participating in the report. “That gap is widening and creates a significant issue. Consequently, PHEVs emit almost as heavily as petrol cars.”

Key Factors Driving the Emissions Gap

Analysts linked the majority of the gap to overestimates of the “electric driving share” – the percentage of kilometers travelled in electric mode compared to overall mileage. The team found that just a quarter of travel was completed in EV mode, whereas official estimates suggested over four-fifths.

Even, when running in electric mode, emission levels were well above lab estimates. This occurred because electric motors were insufficiently powerful enough to function alone, resulting to combustion motors using fossil fuels for nearly one-third of the travel completed in electric mode.

Regulatory and Economic Consequences

Based on estimates, the lowballing of PHEV emissions allowed four large carmaker companies to avoid over €5bn in fines from 2021 and 2023, by falsely simplifying compliance with EU fleet-average CO₂ targets.

Additionally, owners of PHEVs could pay approximately €500 more annually in operating costs than is estimated under lab conditions.

“The bold statements that automakers like to make about their plug-in hybrid vehicles are clearly far from the mark,” stated a transport expert. “Consumers are being misled into thinking that by buying a PHEV, they are helping the planet and saving money. Actually, PHEVs are little better than standard gas and diesel cars in terms of energy consumption, CO₂ production, and running expenses.”

Political Discussion and Industry Pressure

Hybrid vehicles have lately been brought again into political debates as carmakers have lobbied the EU to relax CO₂ standards. A proposed prohibition on sales of new internal combustion vehicles in 2035 has faced intense lobbying from the car sector and resistance from EU countries with large car manufacturing.

Some high-level officials have proposed plug-in hybrids as a possible “flexibility” option to include in the regulation.

An independent energy policy expert, who was not involved with the study, called the report a “very useful contribution” after a long period in which parts of the car industry claimed there was too little information to properly evaluate real-world CO2 output.

“The results demonstrate, beyond any doubt, that the gap in lab and real-world PHEV energy use and CO₂ emissions is much, much larger than for gasoline or diesel vehicles,” the expert said. “Any regulatory adjustments concerning PHEVs should be implemented with utmost care and considering this data.”