Plug in Hybrid Vehicles Pollute Almost as Heavily as Gasoline Vehicles, Report Reveals

PHEVs release almost five times more planet-heating emissions than official figures indicate, according to a recent analysis.

Widening Gap Between Official and Actual CO2 Output

Data shows that PHEVs release only 19% lower CO₂ than conventional gas and diesel cars, according to analysis carried out by a non-profit organization. This contrasts sharply with laboratory tests, which suggested a three-quarters decrease in emissions.

Analysts studied data from onboard fuel consumption meters of 800,000 cars registered in the EU from 2021 and 2023. They discovered that actual CO₂ emissions from PHEVs in 2023 were 4.9 times greater than lab figures, increased from three and a half times in 2021.

“Real-world CO2 output are increasing, while lab-reported emissions are falling,” said a senior researcher involved in the study. “This gap is growing and creates a serious problem. As a result, PHEVs pollute almost as heavily as petrol vehicles.”

Primary Factors Driving the Discrepancy

Researchers linked the majority of the gap to inflated estimates of the “utility factor” – the percentage of miles driven in electric mode relative to total mileage. They found that just a quarter of travel was completed in EV mode, whereas official estimates suggested over four-fifths.

Even, when running in EV mode, emission levels were significantly higher than lab projections. That happened because EV motors were insufficiently powerful enough to operate alone, resulting to engines using gasoline for almost a third of the travel covered in EV mode.

Regulatory and Financial Consequences

Based on estimates, the lowballing of PHEV emissions enabled several major automaker companies to escape over €5bn in fines between 2021 and 2023, by artificially easing adherence with European Union average fleet CO₂ targets.

Furthermore, drivers of PHEVs would spend approximately €500 more annually in operating expenses than would be estimated under laboratory conditions.

“The bold statements that manufacturers often promote about their PHEV cars are obviously far from the truth,” stated a automotive expert. “Buyers are being misled into thinking that by purchasing a PHEV, they are benefiting the environment and cutting money. Actually, PHEVs are little improved than regular petrol and diesel cars in terms of energy consumption, CO₂ emissions, and running costs.”

Political Debate and Automotive Pressure

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

Several high-level politicians have suggested PHEVs as a potential “flexibility” solution to include in the legislation.

One independent energy policy specialist, who was not involved with the research, called the analysis a “highly valuable addition” after a long period in which parts of the car industry argued there was too little data to properly assess actual emissions.

“The results demonstrate, without question, that the gap between lab and real-world PHEV fuel consumption and CO₂ emissions is much, much greater than for petrol or diesel vehicles,” they stated. “Any policy changes concerning PHEVs should be implemented with utmost care and in the light of this evidence.”