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Plug-in hybrid cars produce almost five times more global warming emissions than lab-reported figures indicate, as per a new analysis.

Growing Discrepancy In Lab and Actual CO2 Output

Statistics shows that PHEVs emit just one-fifth less CO₂ than conventional petrol and diesel vehicles, according to research carried out by a non-profit group. That differs sharply with laboratory estimates, which assumed a three-quarters reduction in pollution.

Analysts examined data from onboard energy use monitors of 800,000 cars sold in the EU between 2021 and 2023. They found that actual CO₂ output from PHEVs in 2023 were 4.9 times greater than lab estimates, up from three and a half times in 2021.

“Real-world emissions are rising, while lab-reported figures are falling,” stated a lead researcher participating in the study. “This gap is growing and creates a serious problem. As a result, PHEVs pollute nearly as much as petrol cars.”

Key Factors Behind the Emissions Gap

Researchers attributed most of the difference to overestimates of the “electric driving share” – the ratio of miles travelled in electric power relative to total distance. The team found that only a quarter of travel was completed in EV mode, whereas official estimates suggested over four-fifths.

Even, when operating in EV mode, pollution amounts were well above lab estimates. This occurred because EV motors were not strong sufficient to function independently, resulting to combustion motors using gasoline for nearly one-third of the distance covered in EV mode.

Regulatory and Economic Implications

Based on calculations, the lowballing of PHEV emissions enabled four major carmaker groups to escape more than €5bn in penalties from 2021 and 2023, by artificially easing adherence with European Union fleet-average CO₂ standards.

Additionally, owners of PHEVs could pay approximately €500 extra per year in running expenses than is assumed under lab tests.

“The strong claims that manufacturers like to make about their plug-in hybrid cars are obviously way off the mark,” commented a automotive analyst. “Consumers are being misled into thinking that by buying a PHEV, they are benefiting the planet and cutting costs. Actually, PHEVs are only slightly improved than regular gas and diesel vehicles in terms of fuel use, CO₂ emissions, and operating expenses.”

Policy Debate and Industry Lobbying

Hybrid vehicles have lately been drawn back into political debates as automakers have pressed the European Union to weaken CO₂ targets. A proposed ban on sales of new internal combustion vehicles in 2035 has faced intense lobbying from the car sector and resistance from EU countries with large automotive industries.

Several senior officials have suggested plug-in hybrids as a potential “compromise” solution to introduce in the legislation.

An external energy economics expert, who was unaffiliated with the research, described the analysis a “very useful contribution” after a long period in which parts of the automotive sector argued there was insufficient information to accurately assess real-world CO2 output.

“The results show, without question, that the difference between official and actual PHEV energy use and CO₂ emissions is much, much larger than for petrol or conventional cars,” the expert said. “Any policy changes regarding PHEVs should be made with extreme care and considering this data.”