🔗 Share this article

PHEVs produce almost five times greater planet-heating pollution than lab-reported figures show, as per a new report.

Widening Discrepancy Between Lab and Actual Emissions

Statistics shows that PHEVs emit just 19% lower CO₂ than conventional petrol and diesel cars, according to research conducted by a advocacy group. That differs significantly with lab tests, which assumed a three-quarters decrease in pollution.

Researchers examined data from in-vehicle energy use monitors of 800,000 cars registered in the EU from 2021 and 2023. The team discovered that actual CO₂ emissions from PHEVs in 2023 were nearly five times higher than lab figures, up from three and a half times in 2021.

“Actual emissions are rising, while lab-reported figures are falling,” said a senior analyst participating in the report. “This discrepancy is growing and creates a serious problem. Consequently, PHEVs pollute nearly as heavily as gasoline vehicles.”

Key Factors Behind the Discrepancy

Researchers linked most of the gap to inflated estimates of the “electric driving share” – the percentage of miles travelled in electric mode compared to total distance. The team determined that only 27% of travel was completed in electric mode, whereas lab estimates suggested 84%.

Even, when running in EV mode, emission amounts were well above official estimates. This occurred because EV motors were not strong enough to function independently, leading to engines using fossil fuels for nearly one-third of the distance completed in electric mode.

Policy and Economic Implications

Based on calculations, the underestimation of PHEV CO2 output enabled four large carmaker companies to avoid more than €5bn in penalties from 2021 and 2023, by falsely simplifying adherence with European Union fleet-average CO₂ standards.

Furthermore, drivers of PHEVs could pay about €500 extra per year in running expenses than is assumed under lab tests.

“The bold claims that automakers often promote about their PHEV vehicles are obviously way off the mark,” commented a automotive expert. “Consumers are being duped into thinking that by purchasing a PHEV, they are helping the environment and cutting money. In reality, PHEVs are little improved than standard petrol and diesel vehicles in terms of energy consumption, CO₂ production, and running expenses.”

Policy Debate and Automotive Pressure

Plug-in hybrid cars have lately been brought again into policy debates as automakers have pressed the EU to weaken CO₂ targets. A proposed ban on new combustion engine cars in 2035 has faced intense pressure from the automotive industry and resistance from EU countries with large car manufacturing.

Some high-level officials have proposed plug-in hybrids as a potential “compromise” solution to include in the regulation.

An external energy policy specialist, who was not involved with the research, described the analysis a “very useful contribution” after a long period in which parts of the automotive industry argued there was insufficient information to properly assess real-world emissions.

“The results show, without question, that the gap between official and actual PHEV energy use and CO₂ output is much, much greater than for petrol or conventional cars,” the expert said. “Any regulatory adjustments concerning PHEVs should be made with utmost caution and in the light of this data.”