Plug-in Hybrid Cars Pollute Nearly as Heavily as Gasoline Vehicles, Study Reveals

Plug-in hybrid cars produce nearly five times greater global warming emissions than lab-reported figures indicate, as per a new report.

Widening Gap In Lab and Actual CO2 Output

Data shows that PHEVs emit just 19% lower CO₂ than conventional gas and diesel cars, based on research conducted by a advocacy organization. That contrasts significantly with lab tests, which suggested a three-quarters decrease in pollution.

Researchers examined information from onboard energy use meters of eight hundred thousand vehicles registered in Europe from 2021 and 2023. They found that actual CO₂ emissions from PHEVs in 2023 were 4.9 times higher than official estimates, increased from three and a half times in 2021.

“Actual CO2 output are rising, while lab-reported figures are falling,” stated a senior analyst participating in the report. “That discrepancy is growing and creates a significant problem. Consequently, PHEVs emit almost as much as gasoline vehicles.”

Key Factors Driving the Discrepancy

Researchers attributed most of the gap to overestimates of the “electric driving share” – the percentage of kilometers travelled in electric mode relative to overall distance. The team found that only 27% of travel was completed in EV mode, whereas official assumptions assumed 84%.

Even, when operating in EV mode, pollution amounts were significantly higher than lab projections. This occurred because electric motors were insufficiently powerful sufficient to function independently, resulting to engines burning gasoline for almost a third of the travel covered in EV mode.

Policy and Economic Implications

Based on calculations, the underestimation of PHEV CO2 output enabled four major automaker companies to avoid over €5bn in fines between 2021 and 2023, by falsely easing adherence with EU fleet-average CO₂ targets.

Additionally, drivers of PHEVs could pay approximately €500 more annually in running expenses than is assumed under laboratory conditions.

“The bold statements that manufacturers often promote about their PHEV vehicles are clearly way off the truth,” stated a transport analyst. “Buyers are being misled into thinking that by purchasing a PHEV, they are helping the planet and cutting money. In reality, PHEVs are little better than standard petrol and diesel vehicles in terms of energy use, CO₂ production, and running costs.”

Policy Debate and Industry Lobbying

Hybrid cars have lately been brought back into policy discussions as carmakers have pressed the European Union to weaken CO₂ targets. A proposed ban on sales of new combustion engine cars in 2035 has faced intense lobbying from the automotive sector and resistance from member states with significant car industries.

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

One external energy policy expert, who was unaffiliated with the study, described the report a “very useful addition” after years in which parts of the automotive industry argued there was too little information to accurately assess real-world CO2 output.

“These findings show, beyond any doubt, that the difference in lab and real-world PHEV fuel consumption and CO₂ emissions is significantly greater than for petrol or diesel vehicles,” the expert said. “Any policy adjustments regarding PHEVs should be implemented with extreme care and in the light of this evidence.”