Plug-in Hybrid Cars Emit Almost as Much as Petrol Cars, Study Reveals

Plug-in hybrid electric vehicles produce nearly 5x greater global warming emissions than official figures show, as per a new analysis.

Widening Gap In Official and Actual CO2 Output

Statistics shows that PHEVs release only 19% less CO₂ than conventional petrol and diesel vehicles, based on analysis conducted by a non-profit group. This contrasts sharply with lab tests, which suggested a 75% decrease in pollution.

Researchers examined information from onboard energy use monitors of eight hundred thousand cars sold in Europe between 2021 and 2023. They discovered that real-world CO₂ output from PHEVs in 2023 were nearly five times higher than official estimates, up from three and a half times in 2021.

“Real-world CO2 output are increasing, while official figures are falling,” said a senior analyst involved in the report. “That gap is growing and creates a serious problem. As a result, PHEVs pollute almost as heavily as petrol vehicles.”

Key Factors Driving the Discrepancy

Researchers linked most of the difference to inflated estimates of the “electric driving share” – the ratio of miles driven in electric mode relative to overall distance. The team found that just a quarter of driving was done in EV mode, whereas official assumptions assumed over four-fifths.

Even, when running in EV mode, pollution amounts were significantly higher than lab projections. This happened because EV motors were insufficiently powerful sufficient to function independently, resulting to combustion motors burning fossil fuels for almost a third of the travel covered in electric mode.

Regulatory and Economic Implications

Based on estimates, the underestimation of PHEV CO2 output allowed four large carmaker companies to escape over €5bn in fines from 2021 and 2023, by falsely simplifying compliance with European Union average fleet CO₂ standards.

Furthermore, owners of PHEVs would pay approximately €500 more per year in operating expenses than is estimated under laboratory tests.

“The bold claims that automakers often promote about their plug-in hybrid vehicles are clearly way off the truth,” stated a transport expert. “Buyers are being duped into thinking that by buying a PHEV, they are helping the environment and cutting costs. In reality, PHEVs are little better than regular petrol and diesel vehicles in terms of fuel consumption, CO₂ production, and running costs.”

Political Discussion and Automotive Pressure

Hybrid vehicles have lately been drawn back into policy debates as carmakers have pressed the EU to relax CO₂ standards. A proposed prohibition on new internal combustion cars in 2035 has faced heavy lobbying from the automotive industry and resistance from member states with large car manufacturing.

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

One independent energy policy expert, who was unaffiliated with the study, described the report a “very useful contribution” after a long period in which parts of the automotive industry argued there was too little data to accurately assess real-world emissions.

“The results show, beyond any doubt, that the gap between lab and real-world PHEV energy use and CO₂ output is much, much greater than for gasoline or diesel cars,” the expert said. “Any policy adjustments regarding PHEVs should be made with extreme caution and in the light of that data.”