🔗 Share this article

PHEVs emit almost 5x greater planet-heating emissions than lab-reported figures indicate, according to a new report.

Widening Gap In Lab and Real-World Emissions

Data shows that PHEVs release only one-fifth less CO₂ than conventional petrol and diesel vehicles, based on analysis conducted by a non-profit organization. This contrasts sharply with lab estimates, which assumed a three-quarters decrease in emissions.

Analysts studied data from in-vehicle energy use meters of eight hundred thousand cars sold in the EU from 2021 and 2023. They found that real-world CO₂ output from PHEVs in 2023 were nearly five times higher than official figures, up from three and a half times in 2021.

“Actual emissions are rising, while official emissions are decreasing,” said a lead researcher participating in the study. “That discrepancy is growing and poses a serious problem. As a result, PHEVs pollute almost as heavily as gasoline cars.”

Key Reasons Behind the Discrepancy

Researchers linked most of the gap to inflated estimates of the “utility factor” – the percentage of miles driven in battery mode relative to overall mileage. They found that just a quarter of travel was completed in electric mode, whereas lab estimates assumed 84%.

Even, when operating in EV mode, emission levels were well above lab projections. That occurred because electric motors were insufficiently powerful sufficient to operate alone, resulting to engines burning gasoline for nearly a third of the travel completed in EV mode.

Policy and Economic Consequences

According to estimates, the lowballing of PHEV CO2 output enabled four large carmaker groups to escape more than €5bn in fines from 2021 and 2023, by falsely easing compliance with EU fleet-average CO₂ targets.

Furthermore, owners of PHEVs would pay about €500 more per year in running expenses than is assumed under lab conditions.

“The bold statements that manufacturers like to make about their plug-in hybrid vehicles are clearly way off the mark,” stated a automotive analyst. “Consumers are being duped into thinking that by purchasing a PHEV, they are benefiting the planet and saving money. In reality, PHEVs are only slightly improved than regular petrol and diesel vehicles in terms of fuel use, CO₂ production, and running expenses.”

Political Debate and Industry Lobbying

Hybrid vehicles have recently been brought again into political discussions as automakers have lobbied the European Union to weaken CO₂ standards. A proposed ban on sales of new combustion engine cars in 2035 has faced heavy lobbying from the car industry and resistance from EU countries with large car manufacturing.

Some senior officials have suggested PHEVs as a potential “compromise” solution to include in the legislation.

An external energy policy specialist, who was unaffiliated with the study, described the analysis a “highly valuable contribution” after a long period in which segments of the automotive sector claimed there was too little data to accurately assess actual CO2 output.

“The results show, without question, that the difference between official and real-world PHEV energy use and CO₂ emissions is significantly greater than for petrol or diesel cars,” they stated. “Any policy adjustments regarding PHEVs should be implemented with extreme care and in the light of this evidence.”