🔗 Share this article

Plug-in hybrid cars emit almost five times greater planet-heating pollution than official figures show, according to a recent analysis.

Growing Gap In Official and Real-World CO2 Output

Data shows that PHEVs emit only 19% lower CO₂ than conventional gas and diesel vehicles, based on research carried out by a advocacy group. That differs significantly with laboratory estimates, which assumed a 75% decrease in pollution.

Analysts examined data from onboard energy use meters of 800,000 cars sold in the EU from 2021 and 2023. They found that real-world CO₂ emissions from PHEVs in 2023 were 4.9 times greater than official figures, increased from three and a half times in 2021.

“Actual CO2 output are rising, while lab-reported figures are falling,” said a lead analyst involved in the report. “That discrepancy is widening and creates a significant issue. As a result, PHEVs emit almost as heavily as petrol vehicles.”

Primary Reasons Driving the Emissions Gap

Researchers attributed the majority of the difference to inflated estimates of the “utility factor” – the percentage of kilometers driven in electric power relative to total mileage. The team found that only a quarter of driving was done in electric mode, while lab assumptions suggested over four-fifths.

Even, when operating in electric mode, pollution levels were well above lab estimates. That happened because electric motors were not strong enough to function independently, resulting to combustion motors using fossil fuels for almost a third of the distance covered in EV mode.

Regulatory and Economic Consequences

Based on estimates, the lowballing of PHEV emissions allowed several large automaker companies to escape more than €5bn in penalties from 2021 and 2023, by falsely easing compliance with EU fleet-average CO₂ targets.

Furthermore, owners of PHEVs would spend approximately €500 more annually in operating expenses than would be assumed under lab tests.

“The strong claims that automakers often promote about their PHEV cars are clearly way off the truth,” stated a transport analyst. “Buyers are being duped into believing that by purchasing a PHEV, they are benefiting the environment and saving costs. Actually, PHEVs are little improved than standard gas and diesel cars in terms of fuel use, CO₂ emissions, and running expenses.”

Policy Debate and Automotive Pressure

Hybrid vehicles have recently been drawn back into political discussions as automakers have pressed the European Union to relax CO₂ standards. A planned prohibition on new combustion engine cars in 2035 has faced intense pressure from the automotive industry and resistance from EU countries with significant car manufacturing.

Several senior officials have proposed plug-in hybrids as a possible “flexibility” option to introduce in the regulation.

An external energy policy expert, who was not involved with the study, called the report a “very useful addition” after years in which segments of the car industry argued there was too little data to accurately evaluate real-world CO2 output.

“These findings show, beyond any doubt, that the gap between official and real-world PHEV fuel consumption and CO₂ emissions is much, much larger than for petrol or conventional vehicles,” they stated. “All regulatory adjustments concerning PHEVs should be implemented with extreme care and considering that evidence.”