Plug-in Hybrid Cars Emit Nearly as Much as Gasoline Vehicles, Report Finds

Plug-in hybrid cars release nearly five times greater global warming pollution than lab-reported data indicate, according to a new report.

Growing Discrepancy In Lab and Real-World CO2 Output

Statistics reveals that PHEVs emit just one-fifth lower CO₂ than traditional gas and diesel cars, based on research conducted by a non-profit group. This differs sharply with laboratory estimates, which suggested a three-quarters decrease in emissions.

Researchers studied data from onboard fuel consumption monitors of 800,000 vehicles sold in Europe from 2021 and 2023. They discovered that actual CO₂ output from PHEVs in 2023 were nearly five times greater than official estimates, up from three and a half times in 2021.

“Actual emissions are increasing, while lab-reported emissions are decreasing,” stated a senior researcher involved in the study. “That discrepancy is widening and poses a significant issue. Consequently, PHEVs emit almost as much as gasoline vehicles.”

Key Factors Behind the Discrepancy

Researchers linked most of the difference to overestimates of the “electric driving share” – the ratio of miles travelled in electric power relative to overall distance. They determined that just 27% of travel was done in EV mode, whereas official assumptions assumed over four-fifths.

Additionally, when operating in electric mode, emission levels were significantly higher than official estimates. That happened because EV motors were not strong enough to operate alone, resulting to engines using gasoline for nearly a third of the distance completed in EV mode.

Regulatory and Financial Consequences

According to calculations, the lowballing of PHEV CO2 output allowed several major automaker companies to avoid over €5bn in penalties between 2021 and 2023, by artificially simplifying adherence with EU average fleet CO₂ standards.

Additionally, owners of PHEVs would pay approximately €500 extra per year in running costs than would be assumed under lab conditions.

“The bold claims that manufacturers often promote about their PHEV vehicles are clearly way off the truth,” commented a automotive analyst. “Consumers are being duped into thinking that by buying a PHEV, they are helping the planet and saving costs. Actually, PHEVs are little better than regular gas and diesel cars in terms of energy consumption, CO₂ production, and operating costs.”

Political Discussion and Industry Lobbying

Hybrid cars have recently been brought back into policy debates as automakers have lobbied the EU to weaken CO₂ standards. A planned ban on new internal combustion vehicles in 2035 has faced heavy pressure from the car industry and opposition from member states with significant car manufacturing.

Some high-level officials have suggested PHEVs as a possible “compromise” solution to introduce in the regulation.

One independent energy economics specialist, who was not involved with the research, called the report a “very useful addition” after a long period in which segments of the automotive sector argued there was insufficient information to accurately evaluate real-world CO2 output.

“The results show, beyond any doubt, that the difference between official and actual PHEV energy use and CO₂ output is significantly larger than for gasoline or diesel vehicles,” they stated. “Any regulatory adjustments concerning PHEVs should be made with utmost caution and considering this evidence.”