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Plug-in hybrid cars produce almost 5x more global warming emissions than official figures show, as per a recent analysis.

Widening Discrepancy In Official and Real-World Emissions

Statistics shows that PHEVs emit just 19% lower CO₂ than conventional petrol and diesel vehicles, based on analysis conducted by a advocacy group. That contrasts sharply with lab tests, which assumed a three-quarters reduction in emissions.

Researchers studied information from onboard fuel consumption meters of 800,000 cars registered in Europe from 2021 and 2023. They discovered that actual CO₂ output from PHEVs in 2023 were nearly five times greater than lab estimates, increased from 3.5 times in 2021.

“Real-world CO2 output are increasing, while lab-reported figures are decreasing,” stated a lead researcher involved in the report. “That discrepancy is widening and poses a significant problem. Consequently, PHEVs pollute nearly as much as gasoline vehicles.”

Primary Reasons Driving the Discrepancy

Analysts attributed most of the gap to inflated estimates of the “electric driving share” – the percentage of miles travelled in electric power compared to overall mileage. They determined that just 27% of driving was done in EV mode, whereas lab assumptions assumed over four-fifths.

Additionally, when running in EV mode, pollution amounts were significantly higher than lab estimates. That happened because electric motors were not strong enough to operate alone, resulting to engines burning gasoline for almost a third of the distance covered in EV mode.

Policy and Economic Implications

According to calculations, the underestimation of PHEV CO2 output enabled several major carmaker groups to avoid over €5bn in fines from 2021 and 2023, by artificially easing adherence with EU fleet-average CO₂ targets.

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

“The bold statements that manufacturers often promote about their plug-in hybrid vehicles are clearly far from the mark,” stated a transport expert. “Buyers are being misled into believing that by buying a PHEV, they are helping the planet and cutting money. In reality, PHEVs are little improved than standard petrol and diesel cars in terms of fuel consumption, CO₂ production, and operating expenses.”

Political Debate and Automotive Pressure

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

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

One independent energy economics expert, who was unaffiliated with the research, called the analysis a “very useful contribution” after a long period in which parts of the car industry claimed there was insufficient data to properly assess actual emissions.

“These findings show, without question, that the gap between official and actual PHEV fuel consumption and CO₂ output is significantly greater than for gasoline or diesel cars,” the expert stated. “All policy changes concerning PHEVs should be made with extreme caution and in the light of this data.”