🔗 Share this article

Plug-in hybrid cars emit almost 5x greater global warming pollution than lab-reported figures indicate, according to a recent analysis.

Growing Discrepancy In Official and Actual Emissions

Statistics reveals that PHEVs release just 19% lower CO₂ than conventional gas and diesel vehicles, according to research conducted by a non-profit organization. This contrasts significantly with laboratory tests, which suggested a 75% decrease in pollution.

Researchers studied data from onboard fuel consumption monitors of 800,000 cars sold in the EU from 2021 and 2023. The team found that actual CO₂ output from PHEVs in 2023 were 4.9 times higher than lab estimates, increased from 3.5 times in 2021.

“Real-world CO2 output are rising, while lab-reported emissions are decreasing,” said a senior researcher involved in the study. “This gap is growing and creates a significant issue. As a result, PHEVs pollute almost as heavily as petrol vehicles.”

Primary Reasons Behind the Emissions Gap

Researchers linked the majority of the difference to overestimates of the “utility factor” – the percentage of kilometers travelled in electric power relative to total distance. The team found that just a quarter of driving was completed in electric mode, whereas lab assumptions suggested over four-fifths.

Additionally, when running in electric mode, emission levels were significantly higher than official estimates. That occurred because EV motors were insufficiently powerful sufficient to operate independently, leading to combustion motors using gasoline for almost one-third of the travel covered in electric mode.

Policy and Economic Consequences

According to estimates, the lowballing of PHEV emissions allowed several large automaker companies to escape more than €5bn in penalties from 2021 and 2023, by falsely easing adherence with European Union fleet-average CO₂ standards.

Additionally, owners of PHEVs would pay approximately €500 extra annually in running expenses than would be estimated under laboratory conditions.

“The bold claims that automakers like to make about their PHEV vehicles are obviously way off the truth,” commented a transport analyst. “Consumers are being duped into thinking that by purchasing a PHEV, they are benefiting the planet and cutting money. Actually, PHEVs are little better than regular petrol and diesel cars in terms of fuel consumption, CO₂ emissions, and operating costs.”

Policy Debate and Industry Lobbying

Plug-in hybrid cars have recently been drawn back into policy discussions as carmakers have lobbied the EU to weaken CO₂ targets. A planned prohibition on sales of new internal combustion cars in 2035 has faced intense lobbying from the automotive industry and opposition from member states with large automotive industries.

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

One external energy economics expert, who was not involved with the study, described the analysis a “highly valuable contribution” after a long period in which parts of the car sector argued there was insufficient data to properly assess real-world CO2 output.

“These findings show, without question, that the difference in lab and actual PHEV energy use and CO₂ emissions is significantly larger than for petrol or diesel cars,” they stated. “All regulatory adjustments regarding PHEVs should be implemented with extreme caution and considering this evidence.”