Plug-in Hybrid Vehicles Emit Almost as Heavily as Gasoline Cars, Study Reveals

Plug-in hybrid electric vehicles release nearly 5x greater planet-heating pollution than lab-reported data indicate, as per a recent report.

Growing Discrepancy Between Lab and Actual Emissions

Statistics shows that PHEVs emit just 19% less CO₂ than traditional petrol and diesel cars, based on analysis conducted by a non-profit organization. This contrasts sharply with lab tests, which assumed a three-quarters decrease in emissions.

Analysts studied information from in-vehicle fuel consumption monitors of 800,000 vehicles registered in the EU from 2021 and 2023. The team discovered that real-world CO₂ output from PHEVs in 2023 were nearly five times greater than official figures, increased from three and a half times in 2021.

“Actual CO2 output are increasing, while official emissions are falling,” stated a lead analyst involved in the report. “This discrepancy is widening and poses a serious problem. Consequently, PHEVs emit nearly as heavily as petrol vehicles.”

Key Reasons Behind the Emissions Gap

Analysts attributed most of the difference to inflated estimates of the “utility factor” – the ratio of kilometers driven in electric power relative to overall mileage. The team found that just 27% of driving was done in EV mode, while official estimates suggested over four-fifths.

Additionally, when running in EV mode, emission amounts were well above lab projections. That occurred because electric motors were insufficiently powerful enough to operate alone, leading to combustion motors burning fossil fuels for nearly a third of the distance covered in electric mode.

Policy and Economic Implications

Based on calculations, the underestimation of PHEV CO2 output enabled several large carmaker companies to escape over €5bn in penalties between 2021 and 2023, by falsely easing compliance with EU average fleet CO₂ standards.

Furthermore, owners of PHEVs would pay about €500 extra per year in running costs than is estimated under lab tests.

“The bold claims that automakers like to make about their PHEV vehicles are clearly far from the truth,” stated a automotive analyst. “Buyers are being misled into believing that by buying a PHEV, they are helping the environment and saving costs. Actually, PHEVs are little better than regular gas and diesel vehicles in terms of energy use, CO₂ emissions, and operating costs.”

Political Discussion and Industry Pressure

Hybrid vehicles have recently been brought back into policy discussions as automakers have lobbied the EU to relax CO₂ standards. A planned prohibition on new combustion engine vehicles in 2035 has faced heavy lobbying from the automotive industry and opposition from EU countries with significant car industries.

Some senior politicians have suggested plug-in hybrids as a possible “compromise” solution to introduce in the regulation.

An external energy economics expert, who was not involved with the study, called the report a “highly valuable contribution” after years in which parts of the automotive industry claimed there was too little information to accurately evaluate actual emissions.

“The results demonstrate, without question, that the gap between official and real-world PHEV fuel consumption and CO₂ emissions is much, much larger than for petrol or diesel vehicles,” they said. “All policy adjustments concerning PHEVs should be implemented with utmost caution and in the light of this evidence.”