Plug in Hybrid Vehicles Emit Nearly as Heavily as Gasoline Vehicles, Study Reveals

Plug-in hybrid cars produce almost 5x greater global warming pollution than official figures indicate, according to a recent report.

Growing Discrepancy Between Official and Actual Emissions

Statistics shows that PHEVs emit only one-fifth less CO₂ than traditional petrol and diesel cars, based on analysis carried out by a advocacy organization. That contrasts significantly with lab estimates, which suggested a three-quarters reduction in emissions.

Analysts studied information from onboard fuel consumption meters of 800,000 cars registered in the EU between 2021 and 2023. The team discovered that real-world CO₂ emissions from PHEVs in 2023 were nearly five times greater than lab figures, increased from 3.5 times in 2021.

“Actual emissions are rising, while official figures are decreasing,” said a senior analyst participating in the report. “This gap is widening and creates a serious issue. As a result, PHEVs pollute nearly as much as gasoline vehicles.”

Key Factors Behind the Discrepancy

Analysts attributed the majority of the difference to overestimates of the “electric driving share” – the percentage of miles driven in battery mode relative to total distance. The team found that just 27% of travel was done in EV mode, while official assumptions suggested over four-fifths.

Additionally, when running in electric mode, emission amounts were significantly higher than official projections. That occurred because electric motors were insufficiently powerful enough to function alone, resulting to combustion motors burning fossil fuels for almost a third of the travel covered in electric mode.

Regulatory and Financial Consequences

According to estimates, the underestimation of PHEV emissions enabled several large automaker groups to escape over €5bn in penalties from 2021 and 2023, by artificially easing compliance with European Union average fleet CO₂ standards.

Additionally, owners of PHEVs would spend about €500 more annually in operating expenses than is estimated under lab conditions.

“The bold statements that automakers like to make about their plug-in hybrid vehicles are obviously far from the truth,” commented a transport expert. “Buyers are being misled into believing that by purchasing a PHEV, they are benefiting the environment and saving money. In reality, PHEVs are little improved than standard gas and diesel cars in terms of energy consumption, CO₂ emissions, and operating costs.”

Policy Discussion and Industry Pressure

Plug-in hybrid cars have recently been brought back into political discussions as carmakers have pressed the EU to weaken CO₂ standards. A proposed prohibition on sales of new combustion engine cars in 2035 has faced heavy lobbying from the car sector and resistance from EU countries with significant car manufacturing.

Several senior officials have proposed plug-in hybrids as a possible “compromise” solution to include in the legislation.

One independent energy policy expert, who was not involved with the study, described the report a “very useful addition” after a long period in which parts of the car industry argued there was insufficient information to accurately assess actual emissions.

“The results demonstrate, without question, that the gap between official and real-world PHEV energy use and CO₂ output is much, much greater than for gasoline or diesel cars,” they stated. “Any regulatory changes concerning PHEVs should be made with utmost care and in the light of this data.”