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Plug-in hybrid electric vehicles release nearly 5x greater planet-heating pollution than official data indicate, as per a recent report.

Growing Discrepancy In Official and Actual Emissions

Data reveals that PHEVs emit only 19% less CO₂ than traditional gas and diesel cars, according to analysis carried out by a non-profit organization. This contrasts sharply with lab estimates, which suggested a three-quarters reduction in pollution.

Analysts studied data from onboard fuel consumption meters of 800,000 vehicles registered in Europe between 2021 and 2023. They discovered that actual CO₂ emissions from PHEVs in 2023 were 4.9 times higher than lab figures, increased from 3.5 times in 2021.

“Actual CO2 output are rising, while official emissions are falling,” said a lead analyst involved in the report. “That discrepancy is widening and creates a significant issue. Consequently, PHEVs emit nearly as heavily as petrol vehicles.”

Primary Reasons Driving the Discrepancy

Analysts linked most of the gap to overestimates of the “utility factor” – the ratio of miles travelled in electric mode relative to total mileage. The team determined that only a quarter of travel was completed in electric mode, whereas lab assumptions assumed 84%.

Even, when running in EV mode, pollution levels were well above lab estimates. This occurred because EV motors were insufficiently powerful enough to operate alone, leading to combustion motors using gasoline for nearly one-third of the distance completed in EV mode.

Policy and Financial Implications

According to estimates, the lowballing of PHEV emissions allowed four large automaker groups to escape more than €5bn in fines from 2021 and 2023, by artificially easing compliance with European Union fleet-average CO₂ targets.

Furthermore, drivers of PHEVs could spend approximately €500 more per year in running expenses than is estimated under laboratory tests.

“The bold statements that automakers like to make about their PHEV cars are clearly far from the mark,” commented a transport analyst. “Buyers are being duped into believing that by purchasing a PHEV, they are benefiting the environment and saving money. In reality, PHEVs are only slightly improved than standard gas and diesel cars in terms of fuel consumption, CO₂ production, and operating costs.”

Policy Discussion and Automotive Lobbying

Plug-in hybrid cars have recently been drawn again into political discussions as carmakers have pressed the European Union to relax CO₂ targets. A proposed prohibition on new internal combustion vehicles in 2035 has faced intense lobbying from the car sector and opposition from EU countries with large automotive industries.

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

One independent energy policy specialist, who was unaffiliated with the study, described the analysis a “very useful contribution” after a long period in which segments of the car industry claimed there was insufficient data to accurately evaluate real-world emissions.

“These findings demonstrate, without question, that the difference in official and actual PHEV fuel consumption and CO₂ output is much, much greater than for gasoline or diesel vehicles,” they stated. “Any regulatory changes concerning PHEVs should be made with extreme care and considering that data.”