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Plug-in hybrid cars produce almost five times greater planet-heating emissions than lab-reported data indicate, as per a recent analysis.

Growing Discrepancy In Official and Actual CO2 Output

Data shows that PHEVs emit only one-fifth lower CO₂ than traditional gas and diesel cars, based on analysis conducted by a advocacy group. That differs significantly with laboratory estimates, which assumed a 75% reduction in emissions.

Analysts examined information from onboard fuel consumption monitors of 800,000 vehicles sold in Europe from 2021 and 2023. The team found that real-world CO₂ output from PHEVs in 2023 were 4.9 times higher than lab estimates, increased from 3.5 times in 2021.

“Actual CO2 output are increasing, while official figures are falling,” said a lead analyst participating in the study. “This gap is widening and creates a significant issue. Consequently, PHEVs pollute almost as much as petrol cars.”

Key Reasons Behind the Emissions Gap

Researchers attributed most of the gap to overestimates of the “utility factor” – the ratio of miles driven in battery power relative to total mileage. They determined that only 27% of travel was done in EV mode, whereas lab estimates suggested over four-fifths.

Additionally, when running in EV mode, emission amounts were well above official estimates. That occurred because electric motors were insufficiently powerful sufficient to operate alone, leading to engines burning fossil fuels for nearly a third of the travel completed in EV mode.

Policy and Economic Consequences

Based on estimates, the lowballing of PHEV CO2 output enabled several large automaker groups to avoid more than €5bn in penalties between 2021 and 2023, by artificially easing adherence with European Union average fleet CO₂ standards.

Additionally, owners of PHEVs would pay approximately €500 more annually in operating expenses than is estimated under laboratory conditions.

“The strong claims that automakers often promote about their plug-in hybrid vehicles are obviously far from the mark,” commented a automotive expert. “Consumers are being duped into thinking that by purchasing a PHEV, they are helping the planet and saving costs. Actually, PHEVs are little better than standard gas and diesel cars in terms of energy use, CO₂ emissions, and running expenses.”

Policy Discussion and Automotive Lobbying

Plug-in hybrid cars have lately been brought back into political discussions as carmakers have pressed the EU to weaken CO₂ targets. A proposed prohibition on new internal combustion vehicles in 2035 has faced heavy lobbying from the car industry and opposition from member states with significant automotive industries.

Several high-level politicians have proposed PHEVs as a possible “compromise” option to introduce in the regulation.

One external energy policy specialist, who was unaffiliated with the study, called the analysis a “very useful contribution” after years in which segments of the automotive sector claimed there was insufficient information to accurately assess actual emissions.

“These findings demonstrate, beyond any doubt, that the difference between official and real-world PHEV energy use and CO₂ emissions is significantly greater than for gasoline or conventional vehicles,” the expert said. “All policy changes concerning PHEVs should be implemented with extreme caution and in the light of this evidence.”