🔗 Share this article

PHEVs release nearly 5x greater planet-heating emissions than official data indicate, as per a recent analysis.

Widening Gap Between Lab and Real-World Emissions

Data shows that PHEVs emit just one-fifth less CO₂ than conventional gas and diesel cars, according to research carried out by a non-profit group. That differs sharply with lab tests, which suggested a 75% reduction in emissions.

Analysts studied information from in-vehicle fuel consumption meters of 800,000 cars sold in the EU from 2021 and 2023. They found that actual CO₂ emissions from PHEVs in 2023 were nearly five times greater than official figures, increased from three and a half times in 2021.

“Actual CO2 output are increasing, while lab-reported figures are falling,” said a lead analyst involved in the report. “That discrepancy is growing and creates a significant issue. Consequently, PHEVs emit almost as heavily as gasoline vehicles.”

Primary Reasons Driving the Discrepancy

Researchers attributed most of the difference to inflated estimates of the “electric driving share” – the percentage of miles travelled in electric mode relative to total mileage. They found that only a quarter of driving was completed in EV mode, whereas lab estimates assumed 84%.

Even, when running in EV mode, pollution levels were well above official estimates. This happened because EV motors were not strong sufficient to function independently, leading to engines burning fossil fuels for nearly a third of the distance completed in electric mode.

Regulatory and Economic Consequences

Based on estimates, the underestimation of PHEV CO2 output allowed four large carmaker companies to escape more than €5bn in penalties from 2021 and 2023, by falsely easing adherence with European Union average fleet CO₂ standards.

Additionally, owners of PHEVs could pay about €500 extra annually in running expenses than would be estimated under lab tests.

“The strong statements that automakers like to make about their plug-in hybrid cars are clearly far from the mark,” commented a automotive analyst. “Buyers are being misled into thinking that by purchasing a PHEV, they are helping the planet and saving money. Actually, PHEVs are only slightly better than regular gas and diesel vehicles in terms of energy use, CO₂ emissions, and operating costs.”

Political Discussion and Industry Lobbying

Plug-in hybrid vehicles have recently been drawn back into political discussions as carmakers have pressed the European Union to relax CO₂ standards. A planned ban on sales of new internal combustion vehicles in 2035 has faced heavy pressure from the car sector and resistance from EU countries with significant automotive industries.

Some senior officials have suggested plug-in hybrids as a potential “flexibility” solution to include in the regulation.

An independent energy economics expert, who was not involved with the research, described the analysis a “highly valuable addition” after years in which segments of the automotive sector argued there was insufficient information to properly assess real-world CO2 output.

“These findings demonstrate, without question, that the gap between official and actual PHEV fuel consumption and CO₂ output is much, much greater than for petrol or conventional cars,” the expert stated. “Any policy changes regarding PHEVs should be made with extreme caution and in the light of that evidence.”