Plug-in Hybrid electric Vehicles Pollute Almost as Heavily as Petrol Vehicles, Report Finds

PHEVs release almost 5x greater global warming emissions than official data show, as per a recent report.

Widening Discrepancy Between Lab and Real-World Emissions

Data shows that PHEVs emit only one-fifth lower CO₂ than conventional petrol and diesel cars, based on research carried out by a non-profit group. That contrasts significantly with laboratory tests, which suggested a three-quarters reduction in pollution.

Analysts examined data from onboard energy use monitors of eight hundred thousand vehicles registered in the EU from 2021 and 2023. They found that actual CO₂ emissions from PHEVs in 2023 were 4.9 times greater than official figures, increased from three and a half times in 2021.

“Real-world emissions are rising, while lab-reported emissions are decreasing,” said a senior analyst participating in the study. “This gap is growing and creates a significant problem. Consequently, PHEVs pollute nearly as heavily as petrol vehicles.”

Primary Factors Behind the Discrepancy

Researchers attributed most of the gap to inflated estimates of the “utility factor” – the percentage of kilometers driven in battery mode compared to total mileage. They found that just 27% of travel was done in EV mode, while official assumptions suggested over four-fifths.

Additionally, when running in EV mode, pollution amounts were significantly higher than lab projections. That happened because EV motors were insufficiently powerful sufficient to function independently, resulting to combustion motors burning fossil fuels for almost one-third of the travel completed in electric mode.

Policy and Financial Implications

According to estimates, the underestimation of PHEV CO2 output allowed several large carmaker groups to avoid over €5bn in penalties from 2021 and 2023, by falsely easing adherence with European Union average fleet CO₂ targets.

Additionally, owners of PHEVs could pay approximately €500 more annually in operating expenses than would be assumed under lab conditions.

“The strong statements that automakers like to make about their PHEV cars are clearly way off the truth,” commented a transport expert. “Buyers are being misled into thinking that by buying a PHEV, they are benefiting the environment and cutting money. In reality, PHEVs are only slightly better than standard gas and diesel vehicles in terms of fuel consumption, CO₂ production, and operating expenses.”

Policy Debate and Automotive Pressure

Hybrid cars have lately been drawn again into political discussions as automakers have pressed the European Union to weaken CO₂ targets. A planned prohibition on sales of new internal combustion cars in 2035 has faced intense lobbying from the car industry and opposition from EU countries with large car industries.

Some senior politicians have suggested PHEVs as a potential “flexibility” option to introduce in the regulation.

One independent energy economics specialist, who was not involved with the research, described the analysis a “very useful addition” after a long period in which segments of the automotive industry claimed there was too little information to accurately assess actual CO2 output.

“The results demonstrate, without question, that the gap between lab and real-world PHEV energy use and CO₂ output is much, much larger than for petrol or diesel cars,” the expert stated. “Any regulatory changes concerning PHEVs should be implemented with extreme caution and considering that data.”