🔗 Share this article

Plug-in hybrid electric vehicles release nearly 5x greater planet-heating emissions than official data show, according to a new analysis.

Growing Gap In Lab and Real-World Emissions

Statistics shows that PHEVs emit only 19% lower CO₂ than traditional gas and diesel vehicles, based on analysis conducted by a advocacy group. That differs significantly with lab estimates, which suggested a 75% decrease in pollution.

Analysts examined data from in-vehicle fuel consumption monitors of eight hundred thousand cars sold in Europe from 2021 and 2023. The team found that actual CO₂ output from PHEVs in 2023 were nearly five times higher than official figures, up from three and a half times in 2021.

“Real-world CO2 output are increasing, while lab-reported figures are falling,” said a lead analyst participating in the report. “That gap is widening and poses a significant problem. As a result, PHEVs emit nearly as heavily as petrol cars.”

Primary Factors Behind the Emissions Gap

Researchers linked most of the difference to inflated estimates of the “utility factor” – the percentage of miles travelled in electric mode compared to overall mileage. They determined that just 27% of travel was completed in EV mode, whereas lab assumptions assumed over four-fifths.

Additionally, when operating in EV mode, emission amounts were well above lab projections. This happened because electric motors were insufficiently powerful enough to function independently, resulting to engines burning fossil fuels for nearly one-third of the travel covered in electric mode.

Regulatory and Financial Implications

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

Additionally, drivers of PHEVs would spend about €500 more per year in running expenses than would be assumed under lab tests.

“The strong statements that manufacturers like to make about their PHEV cars are obviously way off the mark,” stated a automotive analyst. “Consumers are being misled into thinking that by purchasing a PHEV, they are helping the planet and cutting costs. Actually, PHEVs are only slightly better than regular petrol and diesel vehicles in terms of fuel use, CO₂ production, and running expenses.”

Political Discussion and Automotive Pressure

Plug-in hybrid vehicles have recently been brought back into political discussions as automakers have lobbied the European Union to weaken CO₂ standards. A planned ban on sales of new combustion engine vehicles in 2035 has faced intense pressure from the car sector and resistance from member states with large automotive industries.

Some high-level officials have suggested plug-in hybrids as a potential “flexibility” solution to include in the regulation.

One independent energy economics expert, who was not involved with the study, called the report a “very useful contribution” after a long period in which parts of the car sector claimed there was insufficient information to properly assess real-world emissions.

“These findings demonstrate, beyond any doubt, that the gap between lab and actual PHEV energy use and CO₂ output is much, much greater than for petrol or conventional vehicles,” they stated. “All policy adjustments regarding PHEVs should be implemented with utmost care and in the light of this data.”