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PHEVs emit almost 5x greater planet-heating pollution than official data indicate, as per a new analysis.

Growing Discrepancy Between Official and Actual CO2 Output

Data reveals that PHEVs emit just 19% less CO₂ than conventional petrol and diesel cars, based on analysis carried out by a advocacy organization. That contrasts significantly with lab estimates, which assumed a 75% decrease in emissions.

Researchers examined information from in-vehicle energy use monitors of 800,000 vehicles registered in the EU from 2021 and 2023. They found that real-world CO₂ emissions from PHEVs in 2023 were nearly five times greater than lab estimates, up from 3.5 times in 2021.

“Real-world emissions are rising, while lab-reported emissions are falling,” said a senior analyst participating in the study. “This gap is growing and creates a significant problem. As a result, PHEVs pollute almost as much as gasoline cars.”

Key Reasons Behind the Discrepancy

Analysts attributed the majority of the gap to overestimates of the “utility factor” – the ratio of miles travelled in electric power compared to overall distance. The team found that just 27% of travel was completed in EV mode, while lab assumptions suggested 84%.

Even, when operating in EV mode, emission amounts were significantly higher than official projections. This occurred because electric motors were not strong sufficient to operate independently, resulting to combustion motors burning gasoline for almost one-third of the distance covered in EV mode.

Regulatory and Financial Consequences

Based on calculations, the lowballing of PHEV CO2 output allowed four large carmaker groups to escape over €5bn in fines from 2021 and 2023, by falsely easing compliance with European Union average fleet CO₂ targets.

Additionally, drivers of PHEVs would pay approximately €500 extra per year in operating expenses than is estimated under laboratory conditions.

“The strong claims that manufacturers like to make about their PHEV vehicles are obviously far from the mark,” stated a transport expert. “Consumers are being duped into believing that by buying a PHEV, they are helping the environment and cutting money. Actually, PHEVs are only slightly improved than standard gas and diesel vehicles in terms of energy consumption, CO₂ emissions, and operating costs.”

Political Debate and Industry Lobbying

Hybrid cars have recently been drawn again into political debates as automakers have lobbied the EU to weaken CO₂ standards. A planned ban on new internal combustion vehicles in 2035 has faced intense pressure from the car industry and resistance from member states with significant car industries.

Some senior officials have proposed PHEVs as a potential “flexibility” solution to introduce in the legislation.

One independent energy economics expert, who was unaffiliated with the research, called the analysis a “highly valuable contribution” after years in which segments of the car industry argued there was insufficient information to accurately evaluate real-world emissions.

“The results show, beyond any doubt, that the gap in official and actual PHEV fuel consumption and CO₂ output is much, much larger than for gasoline or diesel vehicles,” the expert said. “All regulatory changes concerning PHEVs should be made with extreme caution and considering this data.”