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PHEVs emit almost five times greater global warming pollution than lab-reported figures indicate, according to a recent analysis.

Growing Discrepancy In Official and Real-World CO2 Output

Data reveals that PHEVs emit only 19% less CO₂ than conventional gas and diesel vehicles, according to research carried out by a advocacy organization. That contrasts sharply with lab estimates, which assumed a three-quarters reduction in pollution.

Researchers studied information from in-vehicle fuel consumption monitors of eight hundred thousand vehicles registered in the EU between 2021 and 2023. The team found that actual CO₂ output from PHEVs in 2023 were 4.9 times higher than official estimates, increased from three and a half times in 2021.

“Actual CO2 output are rising, while official emissions are falling,” stated a lead analyst participating in the study. “That discrepancy is widening and poses a significant issue. As a result, PHEVs pollute nearly as much as gasoline vehicles.”

Primary Reasons Driving the Discrepancy

Analysts attributed the majority of the difference to inflated estimates of the “utility factor” – the ratio of kilometers travelled in electric mode relative to overall mileage. They determined that just 27% of driving was completed in EV mode, whereas official assumptions suggested over four-fifths.

Even, when operating in EV mode, emission amounts were well above official projections. This happened because electric motors were not strong enough to function alone, resulting to engines using fossil fuels for almost one-third of the travel completed in electric mode.

Policy and Financial Implications

According to estimates, the lowballing of PHEV CO2 output enabled several large carmaker groups to avoid more than €5bn in penalties between 2021 and 2023, by falsely simplifying compliance with EU average fleet CO₂ targets.

Additionally, drivers of PHEVs would pay about €500 extra per year in running expenses than would be estimated under lab tests.

“The strong statements that manufacturers like to make about their plug-in hybrid cars are obviously way off the mark,” commented a automotive analyst. “Buyers are being duped into thinking that by purchasing a PHEV, they are helping the planet and saving money. Actually, PHEVs are only slightly better than regular gas and diesel vehicles in terms of fuel use, CO₂ production, and running expenses.”

Policy Discussion and Industry Pressure

Hybrid cars have lately been brought back into policy debates as automakers have pressed the European Union to relax CO₂ standards. A planned prohibition on new combustion engine vehicles in 2035 has faced heavy pressure from the car industry and opposition from EU countries with significant car manufacturing.

Several high-level politicians have proposed PHEVs as a potential “compromise” option to include in the legislation.

An external energy economics specialist, who was unaffiliated with the research, called the analysis a “very useful contribution” after years in which segments of the car industry argued there was insufficient data to properly assess real-world CO2 output.

“These findings demonstrate, beyond any doubt, that the gap in official and real-world PHEV energy use and CO₂ output is significantly larger than for petrol or diesel vehicles,” they said. “All policy adjustments regarding PHEVs should be made with utmost care and in the light of this evidence.”