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

Plug-in hybrid electric vehicles produce almost 5x greater planet-heating emissions than official figures show, according to a new report.

Widening Gap Between Official and Real-World Emissions

Data shows that PHEVs release just 19% less CO₂ than conventional petrol and diesel vehicles, based on analysis conducted by a advocacy group. That differs sharply with lab tests, which suggested a three-quarters decrease in emissions.

Researchers examined information from onboard fuel consumption meters of 800,000 vehicles sold in Europe between 2021 and 2023. The team discovered that actual CO₂ emissions from PHEVs in 2023 were nearly five times greater than official figures, up from 3.5 times in 2021.

“Real-world CO2 output are increasing, while official figures are decreasing,” said a senior analyst involved in the study. “This discrepancy is widening and poses a serious problem. Consequently, PHEVs emit almost as heavily as gasoline vehicles.”

Primary Factors Driving the Emissions Gap

Analysts linked the majority of the gap to overestimates of the “electric driving share” – the ratio of kilometers travelled in electric mode relative to overall distance. They determined that just 27% of driving was completed in electric mode, whereas lab assumptions suggested over four-fifths.

Additionally, when running in EV mode, pollution levels were well above official estimates. This occurred because EV motors were not strong enough to operate alone, leading to engines burning fossil fuels for nearly one-third of the travel covered in EV mode.

Policy and Financial Consequences

According to calculations, the lowballing of PHEV CO2 output allowed several large carmaker groups to avoid over €5bn in fines from 2021 and 2023, by falsely easing adherence with EU average fleet CO₂ standards.

Additionally, drivers of PHEVs would pay about €500 extra annually in running expenses than is assumed under lab tests.

“The strong statements that manufacturers like to make about their PHEV vehicles are obviously far from the truth,” commented a transport expert. “Buyers are being duped into thinking that by buying a PHEV, they are helping the planet and cutting costs. Actually, PHEVs are little better than standard gas and diesel cars in terms of fuel consumption, CO₂ emissions, and operating expenses.”

Political Discussion and Automotive Lobbying

Hybrid vehicles have lately been brought back into policy discussions as carmakers have lobbied the European Union to relax CO₂ standards. A proposed ban on sales of new internal combustion cars in 2035 has faced intense pressure from the automotive industry and resistance from EU countries with large automotive manufacturing.

Some high-level politicians have proposed PHEVs as a possible “compromise” option to introduce in the legislation.

An external energy economics expert, who was not involved with the research, described the analysis a “very useful contribution” after a long period in which segments of the car sector argued there was too little data to properly evaluate real-world emissions.

“The results demonstrate, beyond any doubt, that the difference between official and actual PHEV energy use and CO₂ output is much, much greater than for petrol or conventional vehicles,” the expert said. “Any regulatory adjustments concerning PHEVs should be implemented with utmost care and in the light of this evidence.”