Plug-in Hybrid electric Cars Emit Almost as Heavily as Gasoline Vehicles, Study Reveals

PHEVs release almost five times more global warming emissions than lab-reported data indicate, as per a recent analysis.

Widening Discrepancy In Official and Real-World CO2 Output

Data shows that PHEVs emit only 19% less CO₂ than conventional gas and diesel cars, according to research carried out by a non-profit group. This differs significantly with laboratory tests, which suggested a three-quarters reduction in pollution.

Researchers examined information from onboard fuel consumption monitors of 800,000 vehicles registered in Europe between 2021 and 2023. The team discovered that actual CO₂ emissions from PHEVs in 2023 were 4.9 times higher than official estimates, up from three and a half times in 2021.

“Actual emissions are rising, while lab-reported emissions are falling,” said a senior researcher participating in the report. “This gap is growing and poses a significant issue. Consequently, PHEVs pollute almost as much as gasoline vehicles.”

Primary Factors Behind the Emissions Gap

Analysts attributed most of the difference to inflated estimates of the “electric driving share” – the percentage of kilometers driven in battery power compared to overall distance. They found that just a quarter of travel was completed in EV mode, whereas official assumptions assumed 84%.

Even, when operating in EV mode, pollution levels were well above lab estimates. This occurred because electric motors were not strong enough to operate alone, resulting to engines using gasoline for almost one-third of the travel covered in EV mode.

Regulatory and Financial Implications

According to calculations, the underestimation of PHEV CO2 output allowed four major automaker companies to avoid more than €5bn in fines from 2021 and 2023, by artificially simplifying adherence with European Union average fleet CO₂ targets.

Additionally, owners of PHEVs would spend about €500 more annually in operating costs than is estimated under laboratory conditions.

“The strong claims that manufacturers like to make about their plug-in hybrid cars are clearly far from the mark,” commented a transport expert. “Consumers are being misled into believing that by buying a PHEV, they are helping the environment and cutting money. Actually, PHEVs are little better than regular gas and diesel cars in terms of fuel consumption, CO₂ emissions, and running expenses.”

Policy Debate and Industry Lobbying

Plug-in hybrid vehicles have recently been brought again into political discussions as carmakers have lobbied the European Union to relax CO₂ targets. A proposed prohibition on new combustion engine cars in 2035 has faced heavy pressure from the automotive industry and opposition from member states with significant car industries.

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

One independent energy policy expert, who was unaffiliated with the study, described the report a “very useful addition” after years in which segments of the car industry argued there was insufficient data to accurately assess actual CO2 output.

“The results show, beyond any doubt, that the gap between official and real-world PHEV energy use and CO₂ output is significantly greater than for gasoline or diesel cars,” they said. “All policy changes regarding PHEVs should be made with utmost care and in the light of that data.”