🔗 Share this article

Plug-in hybrid cars produce nearly five times more planet-heating emissions than lab-reported figures indicate, according to a new analysis.

Growing Discrepancy In Lab and Actual Emissions

Statistics reveals that PHEVs release only 19% less CO₂ than traditional gas and diesel vehicles, based on analysis carried out by a non-profit organization. This differs significantly with laboratory estimates, which assumed a three-quarters reduction in emissions.

Researchers examined information from in-vehicle energy use meters of eight hundred thousand vehicles sold in the EU between 2021 and 2023. They found that real-world CO₂ emissions from PHEVs in 2023 were nearly five times greater than lab figures, up from 3.5 times in 2021.

“Real-world CO2 output are increasing, while official figures are falling,” stated a senior analyst involved in the study. “This discrepancy is growing and poses a significant issue. As a result, PHEVs pollute almost as much as gasoline cars.”

Primary Factors Driving the Discrepancy

Researchers attributed the majority of the difference to inflated estimates of the “utility factor” – the ratio of miles driven in electric power relative to total mileage. They determined that just a quarter of travel was completed in EV mode, while official assumptions suggested over four-fifths.

Even, when running in electric mode, emission amounts were well above official projections. This occurred because electric motors were insufficiently powerful enough to function independently, resulting to engines using gasoline for nearly one-third of the travel covered in EV mode.

Policy and Financial Consequences

According to calculations, the underestimation of PHEV CO2 output allowed several major automaker companies to avoid over €5bn in penalties from 2021 and 2023, by artificially easing compliance with EU average fleet CO₂ standards.

Furthermore, owners of PHEVs could pay approximately €500 more annually in running expenses than would be estimated under laboratory tests.

“The bold claims that manufacturers like to make about their plug-in hybrid cars are obviously far from the truth,” stated a transport expert. “Consumers are being misled into believing that by buying a PHEV, they are helping the planet and cutting money. In reality, PHEVs are only slightly better than regular gas and diesel vehicles in terms of energy consumption, CO₂ production, and operating costs.”

Political Debate and Automotive Lobbying

Hybrid cars have recently been drawn back into political discussions as carmakers have lobbied the EU to weaken CO₂ targets. A proposed ban on new combustion engine vehicles in 2035 has faced heavy pressure from the automotive sector and opposition from member states with significant car manufacturing.

Several high-level politicians have proposed plug-in hybrids as a possible “flexibility” option to introduce in the regulation.

One independent energy economics specialist, who was not involved with the research, described the analysis a “highly valuable addition” after years in which parts of the car sector claimed there was insufficient data to properly evaluate real-world emissions.

“The results show, beyond any doubt, that the gap between official and real-world PHEV energy use and CO₂ output is significantly larger than for gasoline or diesel vehicles,” the expert said. “Any regulatory adjustments concerning PHEVs should be made with utmost care and in the light of that data.”