🔗 Share this article

Plug-in hybrid electric vehicles produce nearly five times more planet-heating pollution than lab-reported figures indicate, as per a new analysis.

Widening Discrepancy In Official and Actual CO2 Output

Data shows that PHEVs emit just one-fifth less CO₂ than traditional gas and diesel vehicles, according to analysis conducted by a advocacy organization. That contrasts significantly with lab tests, which suggested a three-quarters decrease in emissions.

Analysts examined data from in-vehicle fuel consumption monitors of 800,000 vehicles registered in the EU between 2021 and 2023. The team discovered that real-world CO₂ emissions from PHEVs in 2023 were 4.9 times higher than lab figures, up from 3.5 times in 2021.

“Real-world CO2 output are increasing, while official figures are falling,” stated a senior researcher involved in the study. “This gap is widening and creates a serious issue. As a result, PHEVs emit nearly as much as gasoline vehicles.”

Primary Reasons Driving the Emissions Gap

Analysts linked most of the gap to overestimates of the “utility factor” – the percentage of kilometers driven in battery mode relative to overall mileage. The team determined that only a quarter of driving was completed in EV mode, whereas lab assumptions assumed over four-fifths.

Even, when running in EV mode, emission levels were well above lab projections. This happened because EV motors were insufficiently powerful enough to operate independently, leading to engines burning fossil fuels for nearly a third of the distance covered in electric mode.

Regulatory and Economic Implications

According to estimates, the lowballing of PHEV emissions allowed several large carmaker companies to escape over €5bn in fines between 2021 and 2023, by artificially simplifying adherence with EU average fleet CO₂ standards.

Additionally, drivers of PHEVs would pay about €500 more annually in running expenses than is estimated under laboratory tests.

“The strong claims that manufacturers like to make about their plug-in hybrid vehicles are clearly way off the mark,” commented a transport expert. “Buyers are being misled into thinking that by purchasing a PHEV, they are helping the environment and cutting money. Actually, PHEVs are only slightly improved than regular gas and diesel cars in terms of energy use, CO₂ emissions, and operating costs.”

Policy Discussion and Automotive Lobbying

Plug-in hybrid vehicles have lately been brought again into political debates as automakers have pressed the EU to relax CO₂ targets. A planned ban on new combustion engine cars in 2035 has faced heavy pressure from the car industry and resistance from EU countries with large automotive industries.

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

One external energy policy expert, who was unaffiliated with the research, called the analysis a “highly valuable addition” after years in which segments of the car industry argued there was too little data to accurately assess real-world emissions.

“The results demonstrate, beyond any doubt, that the difference between official and actual PHEV energy use and CO₂ output is significantly greater than for petrol or diesel cars,” the expert said. “Any regulatory changes concerning PHEVs should be implemented with extreme care and in the light of that evidence.”