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Plug-in hybrid cars emit nearly five times greater planet-heating emissions than lab-reported data show, as per a recent report.

Widening Gap Between Lab and Actual Emissions

Statistics reveals that PHEVs emit just one-fifth lower CO₂ than conventional petrol and diesel vehicles, based on analysis carried out by a advocacy organization. This differs significantly with laboratory estimates, which suggested a 75% reduction in emissions.

Analysts studied information from in-vehicle energy use meters of eight hundred thousand cars registered in the EU 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.

“Real-world CO2 output are increasing, while lab-reported figures are decreasing,” said a lead analyst participating in the report. “That discrepancy is growing and creates a serious issue. Consequently, PHEVs pollute nearly as heavily as gasoline cars.”

Primary Factors Driving the Emissions Gap

Analysts attributed most of the gap to overestimates of the “electric driving share” – the percentage of miles travelled in battery mode relative to overall mileage. The team found that only a quarter of travel was done in electric mode, whereas lab assumptions suggested 84%.

Additionally, when running in EV mode, emission amounts were well above official projections. That occurred because electric motors were insufficiently powerful enough to function independently, leading to engines burning gasoline for almost a third of the distance covered in electric mode.

Policy and Economic Implications

According to estimates, the underestimation of PHEV emissions enabled four large carmaker companies to avoid over €5bn in penalties from 2021 and 2023, by falsely easing adherence with European Union average fleet CO₂ standards.

Furthermore, owners of PHEVs could spend approximately €500 more annually in running expenses than is assumed under lab conditions.

“The bold statements that automakers often promote about their plug-in hybrid cars are clearly far from the truth,” stated a automotive expert. “Consumers are being duped into believing that by purchasing a PHEV, they are benefiting the environment and cutting money. Actually, PHEVs are little improved than standard gas and diesel cars in terms of energy use, CO₂ emissions, and operating costs.”

Policy Debate and Industry Lobbying

Plug-in hybrid cars have lately been brought back into political debates as automakers have pressed the EU to relax CO₂ targets. A proposed ban on new combustion engine cars in 2035 has faced heavy pressure from the automotive industry and opposition from EU countries with large automotive manufacturing.

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

One external energy policy expert, who was not involved with the study, described the analysis a “very useful addition” after years in which segments of the automotive industry argued there was too little data to accurately assess real-world CO2 output.

“These findings demonstrate, beyond any doubt, that the gap in lab and real-world PHEV energy use and CO₂ emissions is much, much greater than for gasoline or diesel vehicles,” they stated. “Any policy adjustments regarding PHEVs should be made with utmost care and considering that evidence.”