🔗 Share this article

PHEVs emit almost 5x greater planet-heating emissions than lab-reported data indicate, as per a new analysis.

Growing Discrepancy Between Lab and Real-World CO2 Output

Data reveals that PHEVs emit only 19% less CO₂ than traditional gas and diesel vehicles, according to research conducted by a non-profit group. That contrasts sharply with laboratory tests, which assumed a 75% reduction in emissions.

Researchers studied information from in-vehicle fuel consumption monitors of 800,000 vehicles sold in Europe between 2021 and 2023. The team discovered that real-world CO₂ output from PHEVs in 2023 were nearly five times greater than lab figures, increased from three and a half times in 2021.

“Actual CO2 output are increasing, while lab-reported figures are falling,” said a lead researcher involved in the study. “This discrepancy is growing and creates a significant issue. As a result, PHEVs emit nearly as much as gasoline vehicles.”

Key Factors Driving the Emissions Gap

Analysts attributed most of the difference to overestimates of the “electric driving share” – the ratio of kilometers travelled in electric power compared to total distance. They determined that only 27% of travel was done in EV mode, while lab assumptions assumed 84%.

Even, when operating in EV mode, emission levels were significantly higher than lab estimates. That happened because EV motors were insufficiently powerful enough to operate independently, leading to combustion motors burning fossil fuels for nearly one-third of the distance covered in EV mode.

Regulatory and Economic Consequences

According to calculations, the lowballing of PHEV CO2 output enabled several large automaker groups to escape more than €5bn in fines from 2021 and 2023, by falsely easing compliance with European Union fleet-average CO₂ targets.

Furthermore, drivers of PHEVs could pay about €500 more annually in operating costs than would be estimated under laboratory conditions.

“The strong claims that manufacturers like to make about their PHEV cars are clearly way off the mark,” commented a transport expert. “Consumers are being duped into thinking that by buying a PHEV, they are helping the planet and cutting costs. In reality, PHEVs are only slightly improved than standard gas and diesel vehicles in terms of fuel consumption, CO₂ emissions, and running expenses.”

Policy Discussion and Industry Pressure

Hybrid vehicles have recently been brought again into political discussions as carmakers have lobbied the EU to weaken CO₂ targets. A planned prohibition on new internal combustion vehicles in 2035 has faced intense lobbying from the car sector and opposition from member states with large car industries.

Some senior officials have proposed plug-in hybrids as a possible “compromise” solution to include in the regulation.

One independent energy economics expert, who was not involved with the study, described the analysis a “very useful addition” after a long period in which segments of the automotive industry claimed there was too little information to properly assess actual CO2 output.

“These findings show, beyond any doubt, that the difference between official and actual PHEV energy use and CO₂ output is much, much greater than for gasoline or conventional cars,” the expert stated. “Any policy adjustments concerning PHEVs should be implemented with utmost care and in the light of this evidence.”