🔗 Share this article

Plug-in hybrid cars produce almost 5x greater global warming emissions than lab-reported data show, according to a recent report.

Growing Discrepancy Between Official and Real-World Emissions

Data shows that PHEVs emit just 19% less CO₂ than traditional petrol and diesel vehicles, based on analysis conducted by a advocacy organization. That contrasts sharply with lab tests, which suggested a 75% decrease in emissions.

Analysts studied information from onboard fuel consumption monitors of eight hundred thousand cars sold in Europe between 2021 and 2023. They found that actual CO₂ output from PHEVs in 2023 were nearly five times greater than official figures, increased from 3.5 times in 2021.

“Real-world CO2 output are rising, while official figures are falling,” stated a lead researcher involved in the study. “That gap is widening and poses a significant issue. Consequently, PHEVs emit nearly as heavily as gasoline cars.”

Primary Factors Driving the Discrepancy

Researchers attributed the majority of the difference to overestimates of the “electric driving share” – the percentage of miles driven in battery mode compared to overall mileage. The team found that just a quarter of driving was completed in electric mode, whereas official estimates assumed 84%.

Additionally, when running in electric mode, pollution levels were significantly higher than official projections. That occurred because electric motors were not strong enough to function alone, leading to engines burning fossil fuels for nearly one-third of the travel completed in EV mode.

Policy and Financial Consequences

According to estimates, the lowballing of PHEV CO2 output allowed four major automaker groups to escape more than €5bn in fines from 2021 and 2023, by falsely simplifying compliance with EU average fleet CO₂ targets.

Additionally, drivers of PHEVs could spend approximately €500 more per year in operating expenses than is estimated under laboratory tests.

“The bold statements that manufacturers like to make about their PHEV vehicles are clearly way off the mark,” stated a automotive expert. “Consumers are being misled into believing that by buying a PHEV, they are helping the environment and cutting costs. Actually, PHEVs are only slightly improved than standard petrol and diesel vehicles in terms of fuel use, CO₂ emissions, and operating costs.”

Policy Discussion and Automotive Lobbying

Plug-in hybrid vehicles have recently been drawn again into policy debates as automakers have lobbied the EU to weaken CO₂ targets. A proposed ban on new combustion engine vehicles in 2035 has faced heavy lobbying from the automotive sector and opposition from EU countries with large car manufacturing.

Several high-level politicians have proposed PHEVs as a potential “compromise” option to include in the regulation.

An external energy policy expert, who was unaffiliated with the study, described the analysis a “highly valuable addition” after a long period in which segments of the automotive sector claimed there was too little information to accurately assess actual CO2 output.

“These findings demonstrate, without question, that the gap between official and actual PHEV energy use and CO₂ output is significantly larger than for petrol or conventional vehicles,” the expert stated. “Any policy adjustments concerning PHEVs should be made with extreme caution and in the light of that data.”