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

Plug-in hybrid cars emit nearly 5x more global warming emissions than official figures show, according to a recent report.

Widening Gap In Official and Real-World Emissions

Statistics reveals that PHEVs emit only 19% lower CO₂ than conventional petrol and diesel cars, based on analysis carried out by a non-profit group. That differs significantly with laboratory tests, which suggested a three-quarters reduction in pollution.

Researchers studied information from onboard fuel consumption meters of 800,000 cars sold in the EU between 2021 and 2023. They found that real-world CO₂ emissions from PHEVs in 2023 were 4.9 times higher than official estimates, up from three and a half times in 2021.

“Actual CO2 output are rising, while official emissions are falling,” stated a lead analyst involved in the study. “This discrepancy is growing and poses a significant issue. Consequently, PHEVs emit almost as much as gasoline vehicles.”

Primary Factors Behind the Discrepancy

Analysts linked most of the gap to overestimates of the “utility factor” – the percentage of miles driven in battery mode compared to overall mileage. The team found that just 27% of driving was done in EV mode, whereas official estimates suggested over four-fifths.

Even, when running in EV mode, emission amounts were significantly higher than lab projections. This occurred because EV motors were insufficiently powerful sufficient to operate independently, leading to engines using fossil fuels for nearly a third of the travel covered in EV mode.

Policy and Economic Consequences

Based on estimates, the underestimation of PHEV CO2 output enabled several large carmaker groups to avoid over €5bn in penalties from 2021 and 2023, by falsely simplifying adherence with EU average fleet CO₂ targets.

Furthermore, drivers of PHEVs would pay about €500 extra annually in running costs than is assumed under lab conditions.

“The bold statements that manufacturers like to make about their PHEV vehicles are obviously far from the truth,” stated a automotive analyst. “Consumers are being duped into thinking that by buying a PHEV, they are benefiting the environment and saving costs. In reality, PHEVs are only slightly improved than standard gas and diesel vehicles in terms of fuel consumption, CO₂ production, and operating costs.”

Political Debate and Industry Lobbying

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

Several senior officials have proposed plug-in hybrids as a possible “flexibility” option to include in the legislation.

One independent energy economics specialist, who was not involved with the study, called the report a “highly valuable addition” after a long period in which parts of the car industry claimed there was too little data to accurately assess real-world CO2 output.

“The results demonstrate, without question, that the difference between lab and actual PHEV fuel consumption and CO₂ output is significantly larger than for petrol or conventional vehicles,” the expert stated. “All policy adjustments regarding PHEVs should be implemented with extreme care and in the light of this evidence.”