Plug-in Hybrid Cars Emit Nearly as Heavily as Gasoline Vehicles, Study Reveals

Plug-in hybrid electric vehicles produce almost 5x greater global warming emissions than lab-reported figures show, according to a recent analysis.

Growing Gap In Lab and Actual Emissions

Data reveals that PHEVs emit just one-fifth less CO₂ than conventional gas and diesel vehicles, based on analysis carried out by a non-profit group. This differs significantly with laboratory tests, which assumed a three-quarters reduction in pollution.

Analysts studied data from in-vehicle fuel consumption meters of eight hundred thousand vehicles registered in the EU from 2021 and 2023. They discovered that real-world CO₂ emissions from PHEVs in 2023 were 4.9 times higher than official figures, up from three and a half times in 2021.

“Actual CO2 output are increasing, while lab-reported emissions are decreasing,” said a lead researcher involved in the report. “This gap is growing and poses a serious problem. Consequently, PHEVs emit almost as heavily as gasoline cars.”

Key Reasons Driving the Emissions Gap

Analysts attributed most of the difference to inflated estimates of the “utility factor” – the ratio of miles driven in electric power relative to total distance. The team determined that just a quarter of travel was completed in EV mode, whereas official assumptions assumed over four-fifths.

Even, when operating in electric mode, pollution levels were significantly higher than lab estimates. That occurred because EV motors were insufficiently powerful sufficient to operate alone, resulting to engines burning fossil fuels for nearly one-third of the travel completed in EV mode.

Policy and Financial Implications

Based on calculations, the underestimation of PHEV emissions allowed four large automaker groups to avoid more than €5bn in penalties between 2021 and 2023, by artificially simplifying adherence with European Union average fleet CO₂ targets.

Furthermore, drivers of PHEVs could pay about €500 extra per year in running expenses than is assumed under laboratory tests.

“The strong statements that manufacturers like to make about their plug-in hybrid cars are clearly far from the truth,” commented a automotive analyst. “Consumers are being duped into believing that by purchasing a PHEV, they are benefiting the planet and cutting costs. In reality, PHEVs are little improved than standard gas and diesel cars in terms of energy use, CO₂ production, and operating costs.”

Political Discussion and Automotive Lobbying

Hybrid vehicles have recently been brought back into policy discussions as carmakers have lobbied the EU to weaken CO₂ targets. A proposed prohibition on new internal combustion cars in 2035 has faced intense lobbying from the car industry and resistance from EU countries with large car industries.

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

One independent energy economics expert, who was not involved with the research, described the analysis a “highly valuable addition” after a long period in which segments of the car sector argued there was insufficient data to properly evaluate actual emissions.

“The results demonstrate, without question, that the gap between official and actual PHEV energy use and CO₂ output is significantly greater than for petrol or conventional vehicles,” the expert said. “All policy adjustments concerning PHEVs should be implemented with extreme care and in the light of this data.”