Plug in Hybrid Vehicles Pollute Almost as Much as Gasoline Vehicles, Study Finds

PHEVs release nearly 5x greater global warming pollution than official figures show, as per a new report.

Growing Gap In Official and Actual CO2 Output

Data reveals that PHEVs emit only 19% less CO₂ than traditional gas and diesel cars, based on research conducted by a non-profit group. This differs significantly with laboratory estimates, which suggested a three-quarters reduction in pollution.

Researchers examined data from onboard energy use meters of 800,000 cars registered in Europe from 2021 and 2023. The team discovered that real-world CO₂ emissions from PHEVs in 2023 were nearly five times higher than official estimates, up from 3.5 times in 2021.

“Real-world CO2 output are increasing, while official figures are falling,” stated a senior researcher involved in the study. “That gap is widening and creates a serious problem. Consequently, PHEVs pollute nearly as heavily as gasoline cars.”

Key Factors Driving the Emissions Gap

Researchers linked most of the gap to overestimates of the “electric driving share” – the percentage of miles travelled in electric mode relative to total distance. The team found that just 27% of travel was completed in EV mode, whereas official estimates assumed over four-fifths.

Additionally, when running in electric mode, emission amounts were significantly higher than lab estimates. That occurred because electric motors were not strong enough to operate alone, leading to combustion motors burning fossil fuels for nearly a third of the travel completed in EV mode.

Regulatory and Economic Consequences

Based on calculations, the underestimation of PHEV emissions enabled several major carmaker groups to avoid more than €5bn in fines from 2021 and 2023, by falsely easing adherence with EU average fleet CO₂ targets.

Furthermore, owners of PHEVs could spend about €500 more per year in running costs than would be assumed under laboratory tests.

“The strong statements that automakers like to make about their PHEV vehicles are obviously way off the truth,” commented a automotive expert. “Buyers are being misled into thinking that by buying a PHEV, they are helping the environment and saving money. Actually, PHEVs are only slightly better than standard petrol and diesel vehicles in terms of fuel use, CO₂ emissions, and operating expenses.”

Political Discussion and Industry Lobbying

Hybrid cars have lately been brought again into policy debates as automakers have lobbied the European Union to weaken CO₂ standards. A proposed ban on new combustion engine vehicles in 2035 has faced heavy lobbying from the car industry and opposition from member states with large car manufacturing.

Several high-level officials have proposed plug-in hybrids as a potential “compromise” solution to introduce in the regulation.

One independent energy economics specialist, who was unaffiliated with the study, called the analysis a “very useful contribution” after years in which segments of the car industry argued there was insufficient information to accurately evaluate real-world emissions.

“The results demonstrate, without question, that the difference in official and actual PHEV energy use and CO₂ emissions is much, much greater than for petrol or diesel vehicles,” they stated. “Any regulatory adjustments regarding PHEVs should be made with utmost care and in the light of this evidence.”