Plug in Hybrid electric Vehicles Pollute Nearly as Heavily as Gasoline Vehicles, Study Reveals

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

Growing Discrepancy Between Lab and Real-World Emissions

Statistics reveals that PHEVs release just 19% less CO₂ than traditional petrol and diesel vehicles, based on research carried out by a non-profit group. That differs significantly with lab tests, which assumed a three-quarters reduction in pollution.

Researchers examined data from onboard energy use meters of eight hundred thousand vehicles registered in the EU from 2021 and 2023. They found that real-world CO₂ emissions from PHEVs in 2023 were nearly five times greater than lab figures, increased from 3.5 times in 2021.

“Real-world CO2 output are increasing, while official figures are decreasing,” said a lead analyst involved in the report. “This gap is growing and creates a serious problem. Consequently, PHEVs pollute almost as much as gasoline cars.”

Primary Factors Driving the Emissions Gap

Analysts linked most of the difference to overestimates of the “electric driving share” – the percentage of miles travelled in battery power relative to overall distance. The team determined that just a quarter of driving was completed in EV mode, whereas lab estimates assumed 84%.

Even, when operating in EV mode, pollution levels were significantly higher than official estimates. That happened because EV motors were not strong enough to operate alone, resulting to engines using gasoline for nearly a third of the distance covered in electric mode.

Regulatory and Economic Consequences

According to calculations, the lowballing of PHEV CO2 output allowed several large automaker companies to escape over €5bn in penalties between 2021 and 2023, by artificially simplifying compliance with EU fleet-average CO₂ standards.

Additionally, owners of PHEVs could pay approximately €500 extra per year in operating expenses than is estimated under laboratory tests.

“The strong statements that manufacturers often promote about their plug-in hybrid vehicles are obviously way off the mark,” commented a transport analyst. “Consumers are being duped into thinking that by buying a PHEV, they are helping the environment and cutting costs. In reality, PHEVs are only slightly improved than regular petrol and diesel vehicles in terms of fuel consumption, CO₂ production, and operating costs.”

Political Discussion and Automotive Pressure

Plug-in hybrid cars have lately been drawn again into political debates as automakers have lobbied the European Union to relax CO₂ targets. A planned ban on sales of new combustion engine cars in 2035 has faced heavy lobbying from the car industry and resistance from EU countries with large automotive industries.

Several high-level politicians have suggested plug-in hybrids as a potential “compromise” option to include in the regulation.

One external energy economics expert, who was not involved with the study, described the report a “highly valuable contribution” after years in which segments of the automotive industry claimed there was too little information to properly evaluate actual CO2 output.

“These findings demonstrate, without question, that the gap between lab and real-world PHEV energy use and CO₂ output is much, much greater than for petrol or diesel vehicles,” the expert stated. “All regulatory adjustments regarding PHEVs should be implemented with extreme care and in the light of this data.”