Plug-in Hybrid electric Cars Pollute Nearly as Much as Petrol Vehicles, Study Finds

Plug-in hybrid cars emit almost 5x greater planet-heating pollution than lab-reported figures indicate, according to a new analysis.

Widening Gap In Lab and Actual CO2 Output

Data shows that PHEVs emit just one-fifth less CO₂ than conventional petrol and diesel cars, based on research conducted by a advocacy organization. That contrasts significantly with lab tests, which suggested a three-quarters reduction in pollution.

Researchers examined data from onboard energy use meters of eight hundred thousand vehicles sold in Europe between 2021 and 2023. The team found that actual CO₂ output from PHEVs in 2023 were 4.9 times greater than lab figures, increased from three and a half times in 2021.

“Actual emissions are rising, while lab-reported figures are decreasing,” stated a senior analyst involved in the study. “That discrepancy is growing and creates a significant issue. As a result, PHEVs emit nearly as heavily as gasoline cars.”

Primary Factors Behind the Emissions Gap

Researchers linked most of the difference to overestimates of the “utility factor” – the ratio of kilometers travelled in electric power compared to total mileage. The team determined that just 27% of travel was done in EV mode, while lab assumptions suggested over four-fifths.

Even, when operating in EV mode, pollution levels were well above official estimates. This happened because electric motors were not strong enough to operate independently, resulting to engines burning fossil fuels for nearly a third of the distance covered in electric mode.

Regulatory and Financial Consequences

According to calculations, the lowballing of PHEV emissions allowed several major carmaker companies to escape more than €5bn in fines from 2021 and 2023, by falsely simplifying compliance with European Union average fleet CO₂ targets.

Furthermore, drivers of PHEVs would pay approximately €500 extra annually in running expenses than would be assumed under laboratory tests.

“The bold claims that automakers like to make about their PHEV cars are obviously far from the truth,” stated a automotive expert. “Consumers are being duped into believing that by purchasing a PHEV, they are helping the planet and cutting money. Actually, PHEVs are little better than standard petrol and diesel cars in terms of fuel use, CO₂ emissions, and operating costs.”

Policy Discussion and Automotive Lobbying

Plug-in hybrid cars have lately been drawn back into political discussions as carmakers have pressed the EU to weaken CO₂ targets. A planned prohibition on new internal combustion cars in 2035 has faced intense lobbying from the automotive sector and opposition from EU countries with significant automotive industries.

Several high-level politicians have suggested plug-in hybrids as a possible “compromise” solution to introduce in the legislation.

One external energy policy expert, who was unaffiliated with the study, called the report a “highly valuable addition” after a long period in which segments of the car sector claimed there was too little data to accurately assess real-world emissions.

“The results show, beyond any doubt, that the gap in official and real-world PHEV energy use and CO₂ emissions is much, much larger than for gasoline or conventional cars,” the expert stated. “All regulatory changes regarding PHEVs should be made with extreme care and considering this data.”