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Plug-in hybrid cars release almost five times more global warming pollution than official figures indicate, as per a recent analysis.

Widening Gap Between Lab and Real-World CO2 Output

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

Analysts studied information from in-vehicle energy use monitors of eight hundred thousand vehicles registered in the EU from 2021 and 2023. They found that actual CO₂ output from PHEVs in 2023 were 4.9 times higher than lab figures, up from three and a half times in 2021.

“Actual CO2 output are increasing, while official emissions are decreasing,” stated a senior analyst involved in the report. “This discrepancy is growing and poses a significant issue. Consequently, PHEVs emit nearly as much as gasoline vehicles.”

Key Factors Driving the Emissions Gap

Analysts linked most of the difference to overestimates of the “utility factor” – the percentage of miles driven in battery power relative to total mileage. They determined that only 27% of driving was done in electric mode, whereas official assumptions assumed over four-fifths.

Additionally, when operating in electric mode, emission amounts were significantly higher than lab projections. That happened because EV motors were not strong enough to function independently, resulting to engines using gasoline for almost one-third of the distance covered in EV mode.

Regulatory and Financial Consequences

Based on estimates, the underestimation of PHEV emissions enabled four large carmaker companies to avoid more than €5bn in penalties from 2021 and 2023, by artificially easing compliance with EU average fleet CO₂ standards.

Furthermore, owners of PHEVs could spend approximately €500 extra annually in running costs than is assumed under laboratory conditions.

“The strong claims that manufacturers like to make about their PHEV vehicles are obviously far from the truth,” stated a transport analyst. “Consumers are being misled into thinking that by buying a PHEV, they are benefiting the environment and cutting money. In reality, PHEVs are only slightly improved than regular petrol and diesel vehicles in terms of energy consumption, CO₂ emissions, and operating expenses.”

Political Debate and Automotive Lobbying

Plug-in hybrid vehicles have lately been brought back into policy discussions as automakers have lobbied the European Union to weaken CO₂ targets. A planned ban on new internal combustion cars in 2035 has faced intense pressure from the automotive industry and resistance from member states with large car manufacturing.

Several senior politicians have suggested plug-in hybrids as a potential “flexibility” option to introduce in the legislation.

One independent energy economics expert, who was not involved with the research, called the report a “very useful addition” after years in which segments of the automotive industry claimed there was too little data to properly evaluate actual emissions.

“The results demonstrate, beyond any doubt, that the difference in lab and actual PHEV energy use and CO₂ emissions is much, much greater than for petrol or conventional vehicles,” they stated. “All regulatory adjustments concerning PHEVs should be implemented with extreme caution and in the light of this data.”