🔗 Share this article

Plug-in hybrid electric vehicles produce nearly 5x more planet-heating pollution than official figures indicate, as per a recent report.

Growing Discrepancy In Lab and Real-World Emissions

Data reveals that PHEVs emit only 19% less CO₂ than traditional petrol and diesel vehicles, based on analysis carried out by a non-profit group. That differs sharply with laboratory estimates, which suggested a 75% reduction in pollution.

Researchers examined information from in-vehicle fuel consumption monitors of eight hundred thousand cars registered in the EU from 2021 and 2023. The team discovered that actual CO₂ emissions from PHEVs in 2023 were nearly five times greater than lab figures, up from three and a half times in 2021.

“Real-world CO2 output are rising, while lab-reported emissions are falling,” stated a senior analyst involved in the report. “This gap is growing and creates a significant problem. As a result, PHEVs emit almost as heavily as gasoline cars.”

Primary Reasons Behind the Discrepancy

Analysts linked the majority of the gap to inflated estimates of the “utility factor” – the percentage of miles travelled in electric mode relative to total distance. They found that just 27% of travel was completed in EV mode, whereas lab estimates suggested 84%.

Even, when running in EV mode, emission amounts were significantly higher than lab projections. This happened because EV motors were not strong enough to function independently, leading to engines using gasoline for almost a third of the travel covered in electric mode.

Regulatory and Financial Consequences

According to calculations, the underestimation of PHEV CO2 output allowed four large carmaker groups to escape over €5bn in fines between 2021 and 2023, by falsely easing compliance with European Union average fleet CO₂ targets.

Furthermore, drivers of PHEVs would spend approximately €500 more annually in operating expenses than would be assumed under lab conditions.

“The bold claims that automakers often promote about their plug-in hybrid vehicles are obviously way off the truth,” stated a automotive analyst. “Consumers are being duped into believing that by purchasing a PHEV, they are benefiting the environment and saving money. Actually, PHEVs are little improved than standard petrol and diesel vehicles in terms of fuel consumption, CO₂ emissions, and operating costs.”

Political Debate and Automotive Pressure

Plug-in hybrid cars have lately been drawn again into policy discussions as automakers have pressed the European Union to relax CO₂ standards. A proposed prohibition on new internal combustion cars in 2035 has faced heavy lobbying from the car industry and resistance from member states with large automotive industries.

Some senior politicians have proposed plug-in hybrids as a potential “flexibility” option to include in the legislation.

An external energy economics expert, who was unaffiliated with the research, described the analysis a “highly valuable contribution” after years in which parts of the car sector argued there was insufficient data to properly assess actual emissions.

“The results demonstrate, beyond any doubt, that the gap between lab and real-world PHEV fuel consumption and CO₂ emissions is much, much greater than for gasoline or conventional cars,” they said. “All policy adjustments regarding PHEVs should be implemented with extreme care and in the light of that data.”