Plug in Hybrid Vehicles Pollute Nearly as Much as Petrol Cars, Report Finds

Plug-in hybrid cars produce nearly five times greater global warming pollution than lab-reported data indicate, as per a new analysis.

Growing Gap Between Official and Real-World Emissions

Data reveals that PHEVs emit just 19% lower CO₂ than traditional petrol and diesel vehicles, according to analysis carried out by a non-profit group. That differs significantly with lab tests, which suggested a three-quarters reduction in pollution.

Researchers examined information from in-vehicle fuel consumption monitors of 800,000 vehicles sold in the EU between 2021 and 2023. The team discovered that actual CO₂ emissions from PHEVs in 2023 were 4.9 times higher than official estimates, increased from 3.5 times in 2021.

“Actual emissions are rising, while lab-reported figures are falling,” stated a senior researcher involved in the report. “That discrepancy is growing and creates a serious problem. As a result, PHEVs pollute nearly as much as petrol vehicles.”

Key Factors Driving the Emissions Gap

Analysts linked most of the difference to inflated estimates of the “electric driving share” – the ratio of miles driven in battery mode relative to overall mileage. The team found that only 27% of driving was done in EV mode, whereas lab estimates suggested 84%.

Additionally, when running in EV mode, emission levels were significantly higher than official estimates. This occurred because electric motors were insufficiently powerful enough to function independently, leading to combustion motors using fossil fuels for almost one-third of the distance completed in electric mode.

Regulatory and Financial Implications

According to estimates, the lowballing of PHEV emissions enabled four major automaker companies to escape over €5bn in penalties from 2021 and 2023, by falsely easing adherence with EU average fleet CO₂ targets.

Furthermore, owners of PHEVs could pay about €500 extra per year in operating expenses than would be assumed under laboratory conditions.

“The bold claims that manufacturers often promote about their plug-in hybrid vehicles are obviously way off the truth,” commented a automotive expert. “Buyers are being misled into believing that by purchasing a PHEV, they are helping the environment and saving costs. In reality, PHEVs are only slightly better than standard petrol and diesel cars in terms of energy consumption, CO₂ production, and running expenses.”

Political Debate and Automotive Lobbying

Plug-in hybrid cars have recently been drawn again into policy debates as automakers have pressed the European Union to weaken CO₂ targets. A proposed ban on new internal combustion vehicles in 2035 has faced heavy lobbying from the car sector and opposition from EU countries with significant car industries.

Several senior officials have suggested plug-in hybrids as a potential “compromise” option to include in the regulation.

One independent energy policy specialist, who was unaffiliated with the research, described the report a “highly valuable addition” after a long period in which segments of the automotive sector argued there was insufficient data to accurately evaluate actual emissions.

“These findings demonstrate, without question, that the gap between lab and real-world PHEV energy use and CO₂ emissions is much, much greater than for gasoline or conventional vehicles,” the expert said. “All policy changes regarding PHEVs should be made with utmost caution and in the light of this data.”