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PHEVs release almost 5x more planet-heating pollution than lab-reported figures indicate, according to a recent report.

Widening Gap In Official and Real-World CO2 Output

Data shows that PHEVs release just 19% less CO₂ than traditional gas and diesel vehicles, according to analysis conducted by a non-profit group. This differs significantly with laboratory tests, which assumed a three-quarters decrease in pollution.

Researchers studied data from in-vehicle fuel consumption monitors of eight hundred thousand vehicles registered in Europe from 2021 and 2023. They discovered that real-world CO₂ emissions from PHEVs in 2023 were 4.9 times higher than lab figures, increased from three and a half times in 2021.

“Actual CO2 output are increasing, while lab-reported figures are decreasing,” stated a lead analyst involved in the study. “That discrepancy is widening and creates a serious issue. Consequently, PHEVs emit almost as much as gasoline vehicles.”

Primary Factors Behind the Emissions Gap

Analysts attributed most of the gap to inflated estimates of the “electric driving share” – the percentage of miles driven in electric mode compared to overall mileage. They determined that only 27% of driving was done in electric mode, while official assumptions suggested 84%.

Additionally, when operating in EV mode, emission levels were significantly higher than lab projections. This happened because EV motors were insufficiently powerful enough to function alone, resulting to combustion motors using fossil fuels for almost one-third of the distance completed in electric mode.

Regulatory and Economic Consequences

According to estimates, the underestimation of PHEV emissions enabled four large automaker groups to escape over €5bn in penalties between 2021 and 2023, by falsely easing adherence with EU average fleet CO₂ standards.

Furthermore, drivers of PHEVs would pay approximately €500 more per year in operating costs than would be assumed under lab conditions.

“The strong statements that manufacturers often promote about their PHEV vehicles are obviously far from the truth,” stated a transport analyst. “Buyers are being misled into thinking that by buying a PHEV, they are benefiting the environment and cutting money. In reality, PHEVs are only slightly improved than standard petrol and diesel vehicles in terms of fuel consumption, CO₂ production, and running expenses.”

Political Discussion and Automotive Lobbying

Plug-in hybrid cars have lately been drawn again into political debates as automakers have lobbied the EU to weaken CO₂ targets. A planned prohibition on sales of new combustion engine vehicles in 2035 has faced intense pressure from the automotive industry and opposition from EU countries with significant car industries.

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

An independent energy policy specialist, who was unaffiliated with the study, called the report a “highly valuable addition” after a long period in which parts of the automotive industry claimed there was insufficient data to accurately evaluate actual emissions.

“These findings demonstrate, without question, that the gap in lab and real-world PHEV fuel consumption and CO₂ emissions is much, much larger than for gasoline or conventional vehicles,” they stated. “Any regulatory changes regarding PHEVs should be implemented with utmost care and in the light of that evidence.”