🔗 Share this article

Plug-in hybrid cars emit almost five times more global warming emissions than lab-reported data show, as per a new analysis.

Growing Discrepancy Between Official and Real-World CO2 Output

Data shows that PHEVs emit just one-fifth less CO₂ than traditional gas and diesel cars, based on analysis conducted by a non-profit organization. This differs significantly with laboratory tests, which assumed a 75% reduction in emissions.

Analysts studied data from in-vehicle fuel consumption meters of 800,000 cars sold in Europe from 2021 and 2023. The team discovered that actual CO₂ output from PHEVs in 2023 were 4.9 times greater than official estimates, up from 3.5 times in 2021.

“Actual emissions are rising, while lab-reported figures are falling,” said a senior researcher participating in the study. “This gap is widening and poses a serious problem. Consequently, PHEVs emit almost as heavily as gasoline cars.”

Key Reasons Driving the Emissions Gap

Researchers attributed most of the gap to overestimates of the “electric driving share” – the percentage of miles driven in electric mode compared to total mileage. They determined that just 27% of travel was done in electric mode, while official estimates assumed over four-fifths.

Even, when operating in EV mode, emission levels were significantly higher than lab projections. That occurred because electric motors were insufficiently powerful enough to operate independently, leading to combustion motors using gasoline for nearly one-third of the travel completed in EV mode.

Regulatory and Economic Consequences

Based on estimates, the lowballing of PHEV emissions allowed several large automaker groups to escape more than €5bn in penalties from 2021 and 2023, by artificially simplifying compliance with EU average fleet CO₂ standards.

Additionally, drivers of PHEVs could spend about €500 extra annually in operating costs than is assumed under lab conditions.

“The bold claims that manufacturers often promote about their PHEV vehicles are obviously way off the mark,” stated a automotive analyst. “Buyers are being misled into believing that by purchasing a PHEV, they are helping the planet and saving money. Actually, PHEVs are little better than regular gas and diesel vehicles in terms of energy use, CO₂ production, and operating expenses.”

Political Discussion and Automotive Pressure

Plug-in hybrid vehicles have lately been brought back into policy debates as automakers have pressed the EU to relax CO₂ targets. A proposed ban on sales of new combustion engine vehicles in 2035 has faced heavy pressure from the automotive sector and opposition from member states with large automotive manufacturing.

Some senior politicians have proposed plug-in hybrids as a possible “flexibility” solution to include in the legislation.

One independent energy policy specialist, who was unaffiliated with the study, called the report a “very useful addition” after a long period in which segments of the automotive industry argued there was too little data to properly assess actual emissions.

“The results demonstrate, beyond any doubt, that the gap in lab and real-world PHEV energy use and CO₂ emissions is significantly larger than for gasoline or diesel cars,” they said. “All regulatory changes concerning PHEVs should be made with extreme caution and considering this evidence.”