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PHEVs produce nearly five times more planet-heating emissions than lab-reported figures show, as per a new analysis.

Widening Gap Between Official and Real-World Emissions

Statistics shows that PHEVs release just one-fifth lower CO₂ than traditional petrol and diesel vehicles, according to research carried out by a advocacy organization. This differs sharply with lab tests, which assumed a three-quarters decrease in emissions.

Analysts examined information from onboard energy use meters of 800,000 cars sold in the EU from 2021 and 2023. The team found that real-world CO₂ emissions from PHEVs in 2023 were nearly five times greater than lab estimates, increased from three and a half times in 2021.

“Real-world CO2 output are increasing, while official figures are decreasing,” said a senior analyst participating in the study. “This discrepancy is widening and poses a serious problem. Consequently, PHEVs emit almost as much as petrol cars.”

Key Factors Behind the Emissions Gap

Analysts attributed the majority of the gap to overestimates of the “electric driving share” – the ratio of kilometers driven in battery mode compared to overall mileage. The team found that just 27% of travel was completed in EV mode, while official estimates suggested over four-fifths.

Even, when running in electric mode, emission amounts were significantly higher than official estimates. This occurred because electric motors were insufficiently powerful enough to operate independently, resulting to combustion motors burning gasoline for nearly a third of the distance completed in EV mode.

Regulatory and Economic Implications

According to calculations, the lowballing of PHEV emissions enabled several large carmaker companies to avoid more than €5bn in penalties from 2021 and 2023, by artificially easing compliance with EU fleet-average CO₂ standards.

Furthermore, owners of PHEVs would pay approximately €500 more per year in operating expenses than would be assumed under laboratory conditions.

“The strong claims that manufacturers often promote about their PHEV vehicles are clearly far from the truth,” stated a automotive analyst. “Buyers are being misled into believing that by buying a PHEV, they are helping the planet and saving costs. Actually, PHEVs are little better than standard gas and diesel vehicles in terms of energy use, CO₂ production, and running costs.”

Policy Debate and Industry Lobbying

Hybrid vehicles have recently been brought again into policy debates as automakers have pressed the European Union to relax CO₂ targets. A planned ban on sales of new combustion engine cars in 2035 has faced intense pressure from the automotive sector and opposition from EU countries with significant car industries.

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

An external energy policy specialist, who was not involved with the study, called the analysis a “very useful contribution” after years in which parts of the automotive industry claimed there was too little data to accurately evaluate real-world CO2 output.

“The results show, without question, that the difference between official and actual PHEV energy use and CO₂ emissions is much, much greater than for petrol or conventional vehicles,” they said. “All regulatory adjustments regarding PHEVs should be implemented with utmost caution and in the light of this data.”