Plug-in Hybrid electric Cars Emit Nearly as Heavily as Petrol Vehicles, Report Reveals

Plug-in hybrid cars produce nearly five times more planet-heating pollution than official figures indicate, according to a new report.

Growing Discrepancy Between Official and Real-World CO2 Output

Data shows that PHEVs release just one-fifth lower CO₂ than conventional gas and diesel cars, based on analysis carried out by a non-profit organization. That contrasts sharply with laboratory estimates, which suggested a 75% reduction in emissions.

Analysts studied information from onboard energy use monitors of eight hundred thousand cars sold in Europe between 2021 and 2023. The team found that real-world CO₂ emissions from PHEVs in 2023 were 4.9 times greater than lab estimates, up from three and a half times in 2021.

“Real-world emissions are rising, while official figures are falling,” said a lead analyst participating in the report. “That discrepancy is growing and poses a significant issue. As a result, PHEVs pollute almost as heavily as gasoline vehicles.”

Key Reasons Behind the Emissions Gap

Researchers attributed most of the difference to inflated estimates of the “utility factor” – the ratio of miles driven in electric power relative to overall distance. They determined that only 27% of travel was completed in electric mode, while official assumptions suggested 84%.

Even, when running in electric mode, emission amounts were significantly higher than official estimates. This happened because EV motors were insufficiently powerful enough to operate alone, leading to engines burning fossil fuels for nearly one-third of the travel covered in EV mode.

Regulatory and Financial Consequences

Based on calculations, the underestimation of PHEV emissions allowed several large automaker groups to avoid more than €5bn in fines between 2021 and 2023, by artificially simplifying adherence with EU average fleet CO₂ standards.

Furthermore, owners of PHEVs would spend about €500 extra annually in running expenses than is assumed under lab conditions.

“The strong statements that automakers like to make about their PHEV cars are obviously far from the mark,” commented a automotive analyst. “Consumers are being misled into believing that by buying a PHEV, they are benefiting the environment and cutting money. Actually, PHEVs are little better than regular petrol and diesel cars in terms of fuel use, CO₂ production, and operating expenses.”

Political Debate and Automotive Lobbying

Hybrid cars have lately been brought back into political discussions as automakers have lobbied the European Union to weaken CO₂ standards. A planned ban on sales of new combustion engine vehicles in 2035 has faced heavy pressure from the automotive sector and opposition from EU countries with significant car manufacturing.

Several senior officials have suggested PHEVs as a possible “flexibility” option to include in the legislation.

An external energy economics specialist, who was not involved with the research, described the analysis a “highly valuable addition” after a long period in which segments of the car industry claimed there was insufficient information to properly evaluate real-world CO2 output.

“The results show, beyond any doubt, that the difference in official and real-world PHEV energy use and CO₂ emissions is much, much greater than for gasoline or conventional vehicles,” the expert said. “All policy changes concerning PHEVs should be made with utmost care and in the light of that evidence.”