Plug-in Hybrid electric Cars Pollute Almost as Heavily as Petrol Vehicles, Report Finds

Plug-in hybrid electric vehicles produce nearly five times more planet-heating pollution than lab-reported data show, as per a new report.

Widening Discrepancy Between Lab and Real-World CO2 Output

Statistics reveals that PHEVs emit just 19% lower CO₂ than conventional petrol and diesel vehicles, according to research carried out by a non-profit group. This differs sharply with laboratory estimates, which assumed a three-quarters decrease in emissions.

Analysts examined data from in-vehicle energy use monitors of eight hundred thousand cars sold in the EU between 2021 and 2023. They discovered that actual CO₂ emissions from PHEVs in 2023 were 4.9 times greater than lab figures, increased from three and a half times in 2021.

“Real-world emissions are rising, while lab-reported emissions are falling,” stated a lead researcher participating in the study. “This gap is widening and creates a significant problem. As a result, PHEVs pollute nearly as much as petrol cars.”

Primary Reasons Driving the Discrepancy

Researchers linked most of the difference to inflated estimates of the “utility factor” – the ratio of kilometers travelled in electric power relative to total mileage. The team determined that only 27% of travel was done in EV mode, whereas official estimates assumed over four-fifths.

Even, when running in EV mode, pollution amounts were significantly higher than lab estimates. This occurred because electric motors were not strong enough to function independently, leading to combustion motors using fossil fuels for nearly a third of the travel covered in electric mode.

Regulatory and Financial Implications

According to estimates, the lowballing of PHEV emissions allowed four large automaker companies to avoid more than €5bn in penalties between 2021 and 2023, by falsely easing adherence with European Union fleet-average CO₂ targets.

Furthermore, drivers of PHEVs could pay about €500 more annually in running expenses than would be estimated under laboratory tests.

“The strong statements that manufacturers often promote about their PHEV vehicles are obviously way off the truth,” stated a automotive analyst. “Buyers are being duped into believing that by purchasing a PHEV, they are benefiting the planet and saving money. In reality, PHEVs are only slightly better than standard petrol and diesel vehicles in terms of fuel consumption, CO₂ emissions, and running costs.”

Policy Debate and Industry Lobbying

Hybrid vehicles have recently been drawn again into political discussions as carmakers have lobbied the European Union to weaken CO₂ standards. A proposed ban on new combustion engine vehicles in 2035 has faced intense pressure from the automotive sector and opposition from EU countries with significant car industries.

Some high-level politicians have proposed plug-in hybrids as a possible “flexibility” solution to include in the regulation.

One external energy economics expert, who was unaffiliated with the study, described the report a “highly valuable addition” after a long period in which parts of the automotive industry claimed there was insufficient information to properly assess actual emissions.

“These findings demonstrate, without question, that the gap between official and real-world PHEV energy use and CO₂ emissions is significantly greater than for gasoline or diesel cars,” the expert said. “Any policy adjustments concerning PHEVs should be implemented with extreme care and in the light of this data.”