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PHEVs produce nearly five times greater planet-heating pollution than lab-reported data indicate, as per a new analysis.

Widening Gap Between Official and Real-World CO2 Output

Data shows that PHEVs release only one-fifth less CO₂ than traditional gas and diesel cars, based on analysis carried out by a advocacy group. This contrasts significantly with lab estimates, which assumed a three-quarters decrease in emissions.

Analysts examined data from onboard fuel consumption monitors of 800,000 vehicles sold in the EU between 2021 and 2023. The team discovered that real-world CO₂ emissions from PHEVs in 2023 were 4.9 times greater than lab figures, up from three and a half times in 2021.

“Real-world emissions are increasing, while official figures are falling,” said a lead researcher involved in the study. “This discrepancy is growing and creates a significant issue. Consequently, PHEVs emit almost as heavily as gasoline vehicles.”

Primary Reasons Behind the Emissions Gap

Analysts linked most of the difference to inflated estimates of the “utility factor” – the percentage of kilometers travelled in battery power compared to total distance. They found that just a quarter of travel was completed in electric mode, while lab assumptions assumed over four-fifths.

Even, when running in EV mode, emission amounts were significantly higher than official projections. This happened because EV motors were not strong sufficient to operate independently, resulting to combustion motors burning fossil fuels for almost one-third of the distance covered in electric mode.

Policy and Economic Implications

According to calculations, the lowballing of PHEV CO2 output enabled several large automaker groups to avoid more than €5bn in fines between 2021 and 2023, by artificially simplifying compliance with European Union average fleet CO₂ standards.

Additionally, drivers of PHEVs could pay about €500 extra annually in operating costs than is assumed under laboratory tests.

“The bold claims that manufacturers like to make about their PHEV vehicles are clearly way off the truth,” stated a transport analyst. “Buyers are being duped into believing that by buying a PHEV, they are helping the environment and cutting costs. In reality, PHEVs are little improved than regular gas and diesel cars in terms of fuel consumption, CO₂ emissions, and operating costs.”

Policy Discussion and Automotive Pressure

Plug-in hybrid cars have lately been brought back into political debates as automakers have lobbied the European Union to relax CO₂ standards. A proposed prohibition on sales of new combustion engine cars in 2035 has faced heavy pressure from the car industry and opposition from EU countries with significant car industries.

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

An independent energy policy specialist, who was unaffiliated with the research, called the analysis a “very useful addition” after years in which segments of the automotive industry argued there was insufficient information to accurately evaluate actual CO2 output.

“These findings show, without question, that the difference in official and real-world PHEV fuel consumption and CO₂ emissions is significantly greater than for gasoline or conventional cars,” the expert said. “All policy adjustments concerning PHEVs should be made with utmost care and considering that data.”