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

Growing Discrepancy Between Lab and Real-World CO2 Output

Statistics shows that PHEVs release only one-fifth lower CO₂ than conventional petrol and diesel vehicles, according to research carried out by a non-profit organization. That contrasts significantly with laboratory estimates, which assumed a three-quarters reduction in pollution.

Analysts examined information from onboard energy use meters of eight hundred thousand cars sold in Europe from 2021 and 2023. The team discovered that real-world CO₂ emissions from PHEVs in 2023 were 4.9 times higher than official estimates, up from 3.5 times in 2021.

“Actual CO2 output are rising, while official figures are decreasing,” stated a senior researcher participating in the report. “This discrepancy is widening and creates a serious issue. As a result, PHEVs pollute nearly as heavily as petrol cars.”

Primary Factors Driving the Emissions Gap

Researchers linked most of the difference to inflated estimates of the “electric driving share” – the percentage of miles driven in electric power compared to total distance. They determined that only 27% of travel was completed in electric mode, whereas official assumptions assumed over four-fifths.

Even, when operating in EV mode, pollution levels were significantly higher than lab estimates. That happened because EV motors were not strong enough to operate independently, resulting to engines using fossil fuels for nearly one-third of the distance covered in electric mode.

Policy and Economic Consequences

Based on calculations, the underestimation of PHEV emissions enabled four large automaker companies to escape more than €5bn in fines between 2021 and 2023, by falsely simplifying compliance with EU average fleet CO₂ standards.

Additionally, owners of PHEVs would pay approximately €500 extra per year in operating costs than is estimated under lab tests.

“The strong claims that manufacturers often promote about their plug-in hybrid cars are clearly way off the mark,” stated a automotive analyst. “Buyers are being duped into believing that by buying a PHEV, they are benefiting the planet and cutting money. In reality, PHEVs are little better than regular gas and diesel cars in terms of fuel use, CO₂ emissions, and operating costs.”

Policy Discussion and Industry Lobbying

Plug-in hybrid cars have recently been drawn again into political debates as carmakers have lobbied the EU to relax CO₂ targets. A planned ban on sales of new internal combustion vehicles in 2035 has faced intense lobbying from the automotive industry and resistance from EU countries with significant car manufacturing.

Some senior officials have suggested PHEVs as a potential “flexibility” option to include in the regulation.

One external energy policy specialist, who was not involved with the study, called the analysis a “highly valuable addition” after years in which parts of the automotive industry claimed there was insufficient information to accurately assess actual CO2 output.

“These findings demonstrate, without question, that the gap in lab and actual PHEV fuel consumption and CO₂ emissions is much, much larger than for petrol or conventional cars,” the expert stated. “Any regulatory adjustments concerning PHEVs should be implemented with extreme caution and in the light of that evidence.”