🔗 Share this article

Plug-in hybrid electric vehicles emit almost five times more global warming pollution than official figures indicate, according to a new analysis.

Growing Discrepancy Between Lab and Real-World CO2 Output

Data reveals that PHEVs emit only 19% less CO₂ than traditional petrol and diesel cars, based on research carried out by a advocacy organization. That differs sharply with lab estimates, which suggested a 75% decrease in pollution.

Researchers studied information from in-vehicle energy use meters of eight hundred thousand cars sold in Europe from 2021 and 2023. The team found that actual CO₂ output from PHEVs in 2023 were 4.9 times greater than lab estimates, increased from three and a half times in 2021.

“Actual emissions are increasing, while lab-reported emissions are falling,” stated a lead researcher involved in the study. “That discrepancy is growing and creates a significant problem. As a result, PHEVs pollute nearly as heavily as petrol cars.”

Key Reasons Driving the Discrepancy

Analysts attributed the majority of the difference to overestimates of the “utility factor” – the ratio of kilometers travelled in electric power compared to total distance. The team found that just a quarter of driving was done in electric mode, while official estimates suggested 84%.

Even, when running in EV mode, emission amounts were well above lab projections. That happened because EV motors were not strong enough to operate independently, leading to combustion motors using fossil fuels for almost a third of the travel covered in EV mode.

Regulatory and Economic Consequences

According to calculations, the underestimation of PHEV emissions enabled several major carmaker groups to avoid more than €5bn in penalties between 2021 and 2023, by falsely easing adherence with EU average fleet CO₂ targets.

Additionally, drivers of PHEVs would spend approximately €500 more per year in operating costs than is assumed under lab conditions.

“The strong claims that manufacturers like to make about their plug-in hybrid vehicles are clearly far from the truth,” stated a automotive expert. “Buyers are being duped into believing that by purchasing a PHEV, they are benefiting the environment and saving money. Actually, PHEVs are little better than standard petrol and diesel cars in terms of fuel consumption, CO₂ production, and running expenses.”

Political Discussion and Industry Lobbying

Plug-in hybrid vehicles have lately been brought again into policy discussions as carmakers have lobbied the European Union to relax CO₂ standards. A proposed prohibition on sales of new internal combustion vehicles in 2035 has faced heavy pressure from the automotive industry and resistance from member states with large car industries.

Several senior officials have suggested PHEVs as a possible “flexibility” solution to introduce in the legislation.

An independent energy policy expert, who was unaffiliated with the research, described the analysis a “very useful contribution” after years in which segments of the automotive sector argued there was insufficient data to properly assess real-world CO2 output.

“The results demonstrate, beyond any doubt, that the difference between lab and real-world PHEV fuel consumption and CO₂ emissions is much, much larger than for gasoline or conventional vehicles,” they said. “Any regulatory changes concerning PHEVs should be made with utmost caution and in the light of this data.”