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PHEVs produce nearly 5x greater global warming pollution than lab-reported figures show, as per a recent analysis.

Growing Discrepancy Between Lab and Real-World Emissions

Statistics shows that PHEVs emit just 19% less CO₂ than traditional petrol and diesel vehicles, based on analysis conducted by a non-profit organization. This contrasts sharply with laboratory tests, which assumed a three-quarters decrease in emissions.

Researchers examined data from onboard energy use meters of 800,000 cars registered in Europe between 2021 and 2023. They discovered that real-world CO₂ output from PHEVs in 2023 were 4.9 times greater than official estimates, increased from 3.5 times in 2021.

“Real-world emissions are increasing, while official figures are falling,” stated a lead analyst participating in the report. “This discrepancy is growing and poses a serious issue. As a result, PHEVs pollute nearly as heavily as petrol cars.”

Key Factors Driving the Discrepancy

Analysts linked the majority of the gap to inflated estimates of the “electric driving share” – the percentage of kilometers driven in battery mode relative to total distance. They found that only 27% of travel was completed in electric mode, while official estimates suggested over four-fifths.

Additionally, when running in electric mode, emission levels were well above official projections. That happened because electric motors were insufficiently powerful sufficient to operate alone, leading to engines using gasoline for almost one-third of the distance completed in EV mode.

Policy and Financial Implications

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

Additionally, owners of PHEVs would spend about €500 extra annually in running expenses than would be assumed under laboratory conditions.

“The strong statements that manufacturers like to make about their PHEV cars are obviously way off the mark,” stated a automotive analyst. “Consumers are being misled into thinking that by buying a PHEV, they are helping the environment and saving costs. Actually, PHEVs are little better than standard petrol and diesel cars in terms of fuel use, CO₂ emissions, and operating expenses.”

Policy Discussion and Industry Pressure

Plug-in hybrid vehicles have recently been brought back into policy debates as automakers have pressed the European Union to relax CO₂ standards. A proposed ban on sales of new internal combustion cars in 2035 has faced heavy pressure from the car sector and opposition from member states with large car manufacturing.

Some senior politicians have proposed PHEVs as a potential “compromise” option to introduce in the legislation.

One independent energy policy specialist, who was unaffiliated with the research, described the analysis a “very useful addition” after years in which segments of the car sector claimed there was insufficient information to accurately assess real-world CO2 output.

“The results show, beyond any doubt, that the gap between lab and real-world PHEV energy use and CO₂ output is much, much greater than for gasoline or diesel vehicles,” the expert stated. “Any regulatory changes regarding PHEVs should be made with utmost caution and in the light of this data.”