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PHEVs produce nearly 5x greater planet-heating emissions than official data show, according to a recent analysis.

Widening Discrepancy Between Official and Real-World Emissions

Statistics shows that PHEVs emit just one-fifth lower CO₂ than conventional gas and diesel cars, according to research carried out by a advocacy organization. That differs significantly with lab tests, which suggested a 75% reduction in pollution.

Analysts examined data from onboard fuel consumption meters of eight hundred thousand vehicles registered in Europe from 2021 and 2023. They found that real-world CO₂ output from PHEVs in 2023 were nearly five times higher than official figures, up from 3.5 times in 2021.

“Actual emissions are increasing, while lab-reported emissions are falling,” said a senior researcher participating in the study. “This gap is widening and poses a significant problem. Consequently, PHEVs emit almost as heavily as petrol cars.”

Primary Reasons Behind the Discrepancy

Analysts linked the majority of the difference to overestimates of the “electric driving share” – the ratio of kilometers travelled in battery mode relative to total mileage. The team determined that just 27% of driving was done in electric mode, whereas official estimates assumed 84%.

Even, when operating in electric mode, emission amounts were well above lab estimates. This occurred because EV motors were not strong sufficient to function independently, resulting to combustion motors burning gasoline for nearly one-third of the travel completed in electric mode.

Policy and Financial Implications

Based on estimates, the underestimation of PHEV CO2 output enabled four major carmaker companies to escape more than €5bn in penalties from 2021 and 2023, by falsely simplifying compliance with EU average fleet CO₂ standards.

Furthermore, owners of PHEVs would pay approximately €500 extra annually in operating expenses than is assumed under lab tests.

“The strong statements that automakers like to make about their PHEV cars are clearly way off the truth,” commented a automotive expert. “Buyers are being duped into believing that by purchasing a PHEV, they are benefiting the environment and saving costs. In reality, PHEVs are little improved than standard gas and diesel cars in terms of fuel use, CO₂ production, and operating expenses.”

Political Discussion and Industry Pressure

Hybrid cars have lately been brought back into policy discussions as automakers have lobbied the European Union to weaken CO₂ standards. A planned ban on new combustion engine cars in 2035 has faced intense pressure from the car industry and opposition from member states with significant automotive industries.

Several senior officials have suggested plug-in hybrids as a possible “flexibility” solution to include in the regulation.

An external energy economics expert, who was unaffiliated with the research, called the report a “highly valuable addition” after a long period in which parts of the automotive industry claimed there was too little data to properly assess actual emissions.

“These findings show, beyond any doubt, that the gap between lab and real-world PHEV fuel consumption and CO₂ output is much, much larger than for petrol or conventional cars,” they stated. “Any regulatory adjustments concerning PHEVs should be made with extreme care and in the light of this data.”