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Plug-in hybrid cars produce nearly 5x more global warming emissions than lab-reported figures show, according to a recent analysis.

Widening Gap In Official and Actual Emissions

Statistics reveals that PHEVs emit only 19% lower CO₂ than conventional gas and diesel cars, based on analysis carried out by a non-profit organization. This differs sharply with laboratory tests, which assumed a 75% reduction in emissions.

Analysts examined information from onboard energy use monitors of eight hundred thousand cars sold in Europe between 2021 and 2023. They discovered that real-world CO₂ output from PHEVs in 2023 were 4.9 times greater than lab estimates, increased from three and a half times in 2021.

“Actual emissions are rising, while official figures are falling,” said a lead researcher participating in the report. “This gap is widening and creates a serious problem. As a result, PHEVs pollute almost as much as petrol cars.”

Primary Factors Driving the Emissions Gap

Researchers linked most of the gap to overestimates of the “utility factor” – the ratio of miles driven in battery power compared to overall distance. They determined that only 27% of driving was completed in EV mode, while official assumptions assumed over four-fifths.

Additionally, when operating in electric mode, emission amounts were well above lab estimates. This occurred because EV motors were insufficiently powerful enough to function alone, resulting to combustion motors using gasoline for nearly one-third of the travel covered in electric mode.

Policy and Financial Consequences

According to calculations, the lowballing of PHEV CO2 output allowed four major carmaker groups to escape more than €5bn in fines between 2021 and 2023, by artificially easing adherence with European Union fleet-average CO₂ standards.

Furthermore, drivers of PHEVs could pay approximately €500 more annually in operating expenses than would be assumed under laboratory tests.

“The strong statements that manufacturers like to make about their plug-in hybrid cars are obviously way off the mark,” stated a automotive expert. “Consumers are being misled into thinking that by purchasing a PHEV, they are benefiting the planet and saving costs. Actually, PHEVs are only slightly improved than regular gas and diesel cars in terms of energy use, CO₂ emissions, and operating costs.”

Policy Debate and Industry Lobbying

Hybrid vehicles have lately been brought again into policy debates as automakers have pressed the European Union to relax CO₂ targets. A proposed prohibition on sales of new combustion engine cars in 2035 has faced intense lobbying from the automotive sector and resistance from EU countries with significant car industries.

Some senior politicians have proposed PHEVs as a potential “compromise” option to include in the regulation.

One independent energy policy specialist, who was not involved with the research, called the report a “very useful addition” after years in which parts of the car industry claimed there was insufficient information to accurately assess real-world emissions.

“These findings demonstrate, beyond any doubt, that the gap in lab and real-world PHEV energy use and CO₂ output is much, much larger than for gasoline or conventional vehicles,” the expert stated. “All policy changes regarding PHEVs should be made with extreme care and in the light of that data.”