Plug-in Hybrid electric Vehicles Pollute Almost as Heavily as Petrol Vehicles, Study Reveals

Plug-in hybrid cars release almost 5x greater planet-heating pollution than lab-reported figures show, according to a new report.

Growing Gap Between Official and Actual CO2 Output

Statistics shows that PHEVs emit just 19% less CO₂ than traditional gas and diesel vehicles, according to research conducted by a non-profit organization. This contrasts significantly with laboratory tests, which suggested a three-quarters decrease in emissions.

Researchers studied information from in-vehicle energy use monitors of eight hundred thousand vehicles registered in Europe from 2021 and 2023. The team found that actual CO₂ emissions from PHEVs in 2023 were nearly five times higher than lab estimates, up from three and a half times in 2021.

“Real-world emissions are increasing, while official emissions are decreasing,” stated a senior analyst participating in the report. “This discrepancy is growing and creates a significant issue. As a result, PHEVs emit nearly as much as gasoline cars.”

Primary Factors Driving the Discrepancy

Researchers attributed most of the gap to overestimates of the “utility factor” – the percentage of miles driven in battery power relative to total mileage. They found that only 27% of travel was completed in EV mode, while lab assumptions assumed 84%.

Even, when running in EV mode, pollution levels were significantly higher than official projections. That happened because electric motors were insufficiently powerful enough to operate alone, resulting to engines burning fossil fuels for almost a third of the travel covered in electric mode.

Regulatory and Economic Implications

According to calculations, the underestimation of PHEV emissions allowed four major automaker companies to avoid more than €5bn in fines from 2021 and 2023, by artificially easing adherence with European Union fleet-average CO₂ standards.

Furthermore, drivers of PHEVs would spend approximately €500 more annually in operating costs than would be estimated under laboratory tests.

“The bold claims that automakers often promote about their PHEV vehicles are clearly far from the truth,” commented a automotive expert. “Consumers are being duped into thinking that by purchasing a PHEV, they are helping the planet and cutting costs. In reality, PHEVs are little better than regular gas and diesel cars in terms of energy consumption, CO₂ production, and running costs.”

Political Discussion and Industry Lobbying

Plug-in hybrid vehicles have recently been drawn back into policy debates as automakers have pressed the EU to relax CO₂ targets. A proposed ban on new internal combustion vehicles in 2035 has faced intense lobbying from the automotive industry and opposition from member states with significant automotive manufacturing.

Some high-level politicians have proposed plug-in hybrids as a potential “compromise” option to include in the regulation.

One independent energy policy specialist, who was not involved with the study, described the analysis a “very useful contribution” after years in which parts of the automotive sector claimed there was insufficient information to accurately assess real-world CO2 output.

“The results show, beyond any doubt, that the gap between official and real-world PHEV energy use and CO₂ emissions is significantly greater than for gasoline or conventional cars,” the expert stated. “Any regulatory changes regarding PHEVs should be implemented with utmost caution and in the light of this evidence.”