Plug-in Hybrid electric Vehicles Emit Nearly as Heavily as Gasoline Cars, Study Finds

PHEVs release nearly five times greater global warming pollution than lab-reported figures indicate, as per a new report.

Growing Discrepancy Between Official and Actual Emissions

Data shows that PHEVs emit just 19% less CO₂ than conventional petrol and diesel cars, according to research carried out by a non-profit organization. This contrasts sharply with lab estimates, which assumed a three-quarters decrease in pollution.

Researchers studied data from in-vehicle energy use monitors of 800,000 vehicles registered in Europe between 2021 and 2023. They discovered that real-world CO₂ output from PHEVs in 2023 were 4.9 times higher than official estimates, increased from three and a half times in 2021.

“Real-world emissions are rising, while lab-reported emissions are falling,” stated a senior analyst participating in the report. “This gap is growing and creates a serious issue. As a result, PHEVs pollute nearly as heavily as gasoline cars.”

Key Factors Driving the Emissions Gap

Analysts attributed the majority of the difference to overestimates of the “electric driving share” – the ratio of kilometers driven in electric power compared to total distance. The team determined that just 27% of driving was done in electric mode, whereas official estimates suggested over four-fifths.

Additionally, when operating in electric mode, emission levels were well above official estimates. That happened because EV motors were insufficiently powerful sufficient to operate independently, leading to combustion motors using fossil fuels for almost one-third of the travel completed in electric mode.

Policy and Economic Consequences

Based on calculations, the lowballing of PHEV CO2 output enabled several major carmaker companies to avoid over €5bn in fines between 2021 and 2023, by falsely simplifying adherence with European Union fleet-average CO₂ targets.

Additionally, owners of PHEVs could spend approximately €500 more annually in operating costs than is estimated under lab tests.

“The strong statements that manufacturers often promote about their PHEV cars are clearly far from the mark,” stated a automotive expert. “Consumers are being duped into thinking that by purchasing a PHEV, they are helping the planet and saving costs. In reality, PHEVs are only slightly better than standard gas and diesel cars in terms of energy use, CO₂ emissions, and running expenses.”

Policy Discussion and Automotive Pressure

Hybrid cars have recently been drawn again into political discussions as carmakers have lobbied the European Union to relax CO₂ standards. A planned prohibition on new combustion engine cars in 2035 has faced heavy pressure from the car industry and opposition from EU countries with significant car industries.

Some high-level officials have suggested plug-in hybrids as a possible “flexibility” option to include in the regulation.

An external energy economics specialist, who was not involved with the study, called the analysis a “highly valuable contribution” after a long period in which parts of the automotive sector claimed there was insufficient information to accurately evaluate real-world CO2 output.

“These findings show, without question, that the difference between lab and actual PHEV energy use and CO₂ emissions is significantly greater than for gasoline or diesel vehicles,” they said. “All policy adjustments regarding PHEVs should be made with utmost caution and considering that evidence.”