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Plug-in hybrid cars release nearly 5x greater global warming emissions than lab-reported figures indicate, as per a recent analysis.

Growing Discrepancy In Lab and Actual Emissions

Data reveals that PHEVs release just 19% lower CO₂ than traditional gas and diesel vehicles, according to analysis conducted by a advocacy organization. This differs sharply with laboratory estimates, which suggested a three-quarters decrease in pollution.

Researchers studied information from onboard energy use meters of eight hundred thousand vehicles sold in the EU between 2021 and 2023. They discovered that real-world CO₂ emissions from PHEVs in 2023 were nearly five times higher than official figures, increased from three and a half times in 2021.

“Actual CO2 output are increasing, while lab-reported emissions are falling,” said a lead researcher involved in the study. “This discrepancy is growing and creates a significant problem. As a result, PHEVs emit nearly as much as petrol vehicles.”

Key Reasons Driving the Emissions Gap

Analysts linked most of the gap to overestimates of the “utility factor” – the percentage of kilometers driven in battery mode relative to overall distance. The team found that just a quarter of driving was done in EV mode, whereas official estimates suggested over four-fifths.

Additionally, when running in electric mode, pollution levels were well above lab projections. This happened because EV motors were insufficiently powerful sufficient to function alone, resulting to engines burning fossil fuels for nearly a third of the distance completed in EV mode.

Policy and Financial Implications

According to calculations, the underestimation of PHEV emissions allowed several large carmaker groups to escape over €5bn in penalties from 2021 and 2023, by artificially easing adherence with European Union average fleet CO₂ targets.

Furthermore, drivers of PHEVs would pay about €500 extra per year in operating costs than would be estimated under laboratory conditions.

“The bold claims that automakers like to make about their plug-in hybrid cars are clearly way off the mark,” commented a transport expert. “Buyers are being duped into believing that by buying a PHEV, they are benefiting the environment and cutting money. Actually, PHEVs are little improved than standard petrol and diesel vehicles in terms of energy consumption, CO₂ emissions, and operating expenses.”

Political Debate and Industry Lobbying

Plug-in hybrid vehicles have recently been brought back into policy discussions as carmakers have pressed the EU to relax CO₂ standards. A planned prohibition on new combustion engine vehicles in 2035 has faced heavy pressure from the car sector and opposition from member states with large automotive manufacturing.

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

An independent energy policy expert, who was unaffiliated with the research, called the report a “highly valuable addition” after a long period in which parts of the car industry argued there was insufficient data to accurately assess actual CO2 output.

“The results demonstrate, beyond any doubt, that the difference in lab and actual PHEV fuel consumption and CO₂ output is significantly larger than for gasoline or conventional vehicles,” the expert said. “All policy adjustments concerning PHEVs should be made with extreme care and in the light of that data.”