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

Plug-in hybrid electric vehicles produce nearly five times more planet-heating pollution than lab-reported figures indicate, according to a new analysis.

Widening Discrepancy In Lab and Real-World CO2 Output

Statistics shows that PHEVs release only 19% lower CO₂ than traditional gas and diesel vehicles, according to research conducted by a advocacy organization. This differs significantly with laboratory estimates, which suggested a 75% reduction in emissions.

Researchers studied information from onboard fuel consumption meters of 800,000 vehicles sold in the EU between 2021 and 2023. They discovered that actual CO₂ emissions from PHEVs in 2023 were nearly five times greater than official figures, up from three and a half times in 2021.

“Actual CO2 output are increasing, while lab-reported emissions are decreasing,” said a senior researcher participating in the study. “This gap is growing and poses a significant problem. As a result, PHEVs pollute nearly as heavily as petrol vehicles.”

Primary Reasons Behind the Discrepancy

Analysts linked the majority of the gap to inflated estimates of the “electric driving share” – the ratio of kilometers travelled in battery mode compared to overall distance. The team determined that only 27% of driving was done in electric mode, whereas lab assumptions assumed over four-fifths.

Even, when running in EV mode, pollution levels were significantly higher than official projections. This happened because electric motors were insufficiently powerful enough to operate alone, leading to engines using gasoline for almost one-third of the distance covered in EV mode.

Regulatory and Economic Consequences

According to estimates, the lowballing of PHEV emissions enabled four large carmaker companies to escape over €5bn in fines between 2021 and 2023, by falsely easing compliance with EU average fleet CO₂ standards.

Additionally, owners of PHEVs would pay approximately €500 more annually in operating expenses than is assumed under laboratory conditions.

“The bold claims that manufacturers often promote about their PHEV vehicles are obviously way off the truth,” commented a transport expert. “Consumers are being duped into believing that by buying a PHEV, they are benefiting the planet and saving money. Actually, PHEVs are little improved than standard petrol and diesel vehicles in terms of energy consumption, CO₂ emissions, and running costs.”

Political Discussion and Industry Lobbying

Plug-in hybrid vehicles have recently been drawn again into policy debates as carmakers have pressed the European Union to weaken CO₂ standards. A planned ban on new internal combustion cars in 2035 has faced intense lobbying from the automotive sector and opposition from EU countries with large car industries.

Several senior officials have suggested PHEVs as a potential “compromise” solution to include in the regulation.

An independent energy economics expert, who was not involved with the study, called the report a “highly valuable addition” after years in which segments of the automotive sector argued there was too little data to properly assess actual emissions.

“These findings show, beyond any doubt, that the difference between lab and actual PHEV fuel consumption and CO₂ output is significantly greater than for gasoline or diesel cars,” the expert said. “All regulatory adjustments regarding PHEVs should be implemented with extreme care and in the light of that evidence.”