🔗 Share this article

PHEVs emit nearly five times more planet-heating pollution than lab-reported data show, according to a new analysis.

Growing Gap In Lab and Actual Emissions

Statistics reveals that PHEVs emit just 19% lower CO₂ than conventional petrol and diesel cars, based on analysis carried out by a advocacy organization. This differs significantly with laboratory estimates, which suggested a 75% decrease in pollution.

Researchers examined information from onboard energy use monitors of eight hundred thousand vehicles sold in Europe from 2021 and 2023. The team found that actual CO₂ output from PHEVs in 2023 were 4.9 times higher than official estimates, up from three and a half times in 2021.

“Real-world emissions are increasing, while lab-reported figures are falling,” said a senior researcher participating in the study. “That discrepancy is widening and creates a significant issue. As a result, PHEVs pollute almost as heavily as gasoline vehicles.”

Primary Reasons Behind the Emissions Gap

Analysts attributed most of the difference to overestimates of the “electric driving share” – the percentage of miles driven in electric power compared to total distance. They determined that just 27% of travel was completed in EV mode, while lab estimates assumed 84%.

Additionally, when running in EV mode, emission amounts were well above lab estimates. That occurred because electric motors were not strong enough to function alone, leading to engines using fossil fuels for almost a third of the travel covered in EV mode.

Policy and Economic Implications

According to calculations, the underestimation of PHEV emissions allowed four major automaker companies to escape over €5bn in penalties between 2021 and 2023, by artificially easing adherence with EU average fleet CO₂ standards.

Furthermore, owners of PHEVs could spend about €500 more per year in operating costs than would be estimated under laboratory tests.

“The bold claims that manufacturers often promote about their plug-in hybrid vehicles are clearly far from the mark,” commented a transport expert. “Consumers are being duped into believing that by buying a PHEV, they are helping the planet and saving money. In reality, PHEVs are little improved than standard gas and diesel vehicles in terms of fuel use, CO₂ emissions, and operating expenses.”

Policy Debate and Automotive Pressure

Plug-in hybrid cars have lately been drawn back into political discussions as carmakers have lobbied the EU to relax CO₂ targets. A proposed prohibition on sales of new combustion engine vehicles in 2035 has faced heavy pressure from the car industry and resistance from member states with significant car industries.

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

One independent energy policy expert, who was unaffiliated with the research, called the analysis a “very useful contribution” after years in which segments of the automotive sector argued there was too little information to properly evaluate actual CO2 output.

“These findings show, without question, that the gap in lab and actual PHEV fuel consumption and CO₂ output is much, much greater than for petrol or conventional cars,” the expert said. “All regulatory adjustments concerning PHEVs should be implemented with extreme care and considering that evidence.”