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PHEVs produce nearly 5x more planet-heating pollution than official figures show, according to a recent analysis.

Widening Gap In Official and Actual Emissions

Data reveals that PHEVs release only one-fifth lower CO₂ than conventional gas and diesel cars, according to research conducted by a advocacy group. This differs sharply with laboratory tests, which assumed a three-quarters decrease in pollution.

Analysts examined data from onboard fuel consumption monitors of eight hundred thousand vehicles registered in Europe between 2021 and 2023. The team discovered that actual CO₂ output from PHEVs in 2023 were nearly five times greater than lab estimates, up from three and a half times in 2021.

“Real-world CO2 output are increasing, while official emissions are decreasing,” said a lead researcher involved in the report. “This gap is growing and creates a significant issue. As a result, PHEVs pollute almost as much as gasoline vehicles.”

Key Factors Behind the Emissions Gap

Researchers attributed the majority of the difference to overestimates of the “electric driving share” – the ratio of miles travelled in battery power compared to total mileage. The team determined that only 27% of driving was completed in electric mode, whereas lab assumptions suggested 84%.

Even, when operating in EV mode, pollution levels were well above lab projections. That occurred because electric motors were not strong enough to function alone, resulting to engines burning gasoline for almost one-third of the distance completed in electric mode.

Policy and Financial Consequences

Based on calculations, the lowballing of PHEV emissions allowed four large carmaker companies to avoid more than €5bn in penalties between 2021 and 2023, by falsely simplifying adherence with European Union average fleet CO₂ standards.

Furthermore, owners of PHEVs could spend about €500 more annually in operating expenses than is assumed under lab conditions.

“The bold statements that automakers like to make about their PHEV cars are obviously way off the mark,” stated a transport expert. “Buyers are being misled into thinking that by buying a PHEV, they are helping the planet and saving costs. In reality, PHEVs are only slightly improved than standard gas and diesel cars in terms of energy use, CO₂ production, and running expenses.”

Policy Discussion and Industry Pressure

Hybrid cars have recently been brought again into policy discussions as carmakers have pressed the European Union to weaken CO₂ targets. A proposed ban on sales of new combustion engine vehicles in 2035 has faced heavy pressure from the car sector and opposition from member states with significant car industries.

Some high-level officials have proposed PHEVs as a potential “compromise” option to introduce in the regulation.

One external energy economics expert, who was not involved with the study, described the report a “highly valuable addition” after years in which segments of the automotive sector argued there was insufficient information to accurately assess actual CO2 output.

“The results demonstrate, beyond any doubt, that the difference in lab and actual PHEV energy use and CO₂ emissions is significantly larger than for gasoline or diesel cars,” they stated. “Any policy changes concerning PHEVs should be made with utmost care and in the light of this evidence.”