Plug in Hybrid Cars Pollute Nearly as Much as Petrol Vehicles, Study Reveals

Plug-in hybrid electric vehicles produce almost 5x more planet-heating pollution than official figures indicate, as per a new analysis.

Growing Discrepancy In Official and Real-World CO2 Output

Data shows that PHEVs emit just 19% less CO₂ than traditional petrol and diesel cars, according to research conducted by a non-profit group. That differs sharply with laboratory tests, which suggested a 75% reduction in emissions.

Analysts studied data from in-vehicle energy use meters of 800,000 cars registered in the EU from 2021 and 2023. They discovered that actual CO₂ emissions from PHEVs in 2023 were 4.9 times higher than lab figures, increased from three and a half times in 2021.

“Actual emissions are rising, while lab-reported figures are decreasing,” said a lead analyst involved in the report. “That discrepancy is widening and creates a significant problem. Consequently, PHEVs emit almost as heavily as gasoline cars.”

Key Factors Behind the Emissions Gap

Analysts attributed the majority of the difference to inflated estimates of the “utility factor” – the percentage of kilometers travelled in battery power relative to total mileage. The team determined that only 27% of driving was done in electric mode, while official estimates assumed over four-fifths.

Even, when operating in electric mode, pollution levels were well above official estimates. This occurred because EV motors were not strong sufficient to operate alone, resulting to engines using gasoline for almost a third of the travel completed in electric mode.

Regulatory and Economic Consequences

According to estimates, the underestimation of PHEV emissions allowed several large automaker companies to avoid more than €5bn in fines between 2021 and 2023, by artificially easing compliance with EU fleet-average CO₂ standards.

Furthermore, owners of PHEVs could pay about €500 extra per year in operating costs than is estimated under laboratory conditions.

“The strong claims that automakers often promote about their PHEV cars are obviously far from the truth,” commented a automotive expert. “Consumers are being duped into thinking that by purchasing a PHEV, they are benefiting the planet and cutting costs. In reality, PHEVs are little better than regular gas and diesel vehicles in terms of fuel use, CO₂ production, and running expenses.”

Political Debate and Industry Pressure

Hybrid vehicles have lately been drawn again into political debates as carmakers have pressed the European Union to relax CO₂ targets. A proposed ban on sales of new combustion engine vehicles in 2035 has faced heavy pressure from the automotive sector and resistance from EU countries with large automotive industries.

Several senior politicians have suggested plug-in hybrids as a possible “flexibility” option to introduce in the regulation.

An independent energy policy specialist, who was not involved with the research, called the analysis a “very useful contribution” after a long period in which segments of the automotive sector claimed there was too little data to properly evaluate real-world CO2 output.

“The results demonstrate, without question, that the gap between official and actual PHEV energy use and CO₂ emissions is much, much larger than for gasoline or diesel cars,” the expert stated. “Any policy adjustments regarding PHEVs should be implemented with extreme care and in the light of that evidence.”