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PHEVs release nearly 5x greater global warming pollution than lab-reported data show, as per a new report.

Widening Gap Between Lab and Actual CO2 Output

Statistics reveals that PHEVs emit just 19% less CO₂ than traditional gas and diesel cars, based on research carried out by a non-profit organization. This differs sharply with laboratory tests, which suggested a 75% decrease in pollution.

Analysts examined information from in-vehicle energy use monitors of 800,000 vehicles sold in Europe from 2021 and 2023. They found that actual CO₂ output from PHEVs in 2023 were nearly five times higher than lab figures, increased from 3.5 times in 2021.

“Actual emissions are increasing, while lab-reported emissions are falling,” stated a senior researcher participating in the report. “This gap is widening and poses a significant issue. As a result, PHEVs emit almost as much as petrol vehicles.”

Key Factors Driving the Emissions Gap

Researchers attributed most of the difference to inflated estimates of the “electric driving share” – the ratio of miles driven in battery power relative to total mileage. The team found that just a quarter of travel was done in electric mode, whereas lab assumptions suggested over four-fifths.

Additionally, when operating in electric mode, emission levels were significantly higher than lab projections. That occurred because electric motors were insufficiently powerful enough to function independently, resulting to engines burning gasoline for almost a third of the distance covered in electric mode.

Policy and Economic Consequences

According to calculations, the lowballing of PHEV emissions allowed several major automaker groups to avoid more than €5bn in penalties between 2021 and 2023, by falsely simplifying adherence with EU fleet-average CO₂ standards.

Additionally, drivers of PHEVs could spend about €500 extra per year in operating expenses than would be assumed under laboratory conditions.

“The strong statements that manufacturers often promote about their PHEV vehicles are clearly way off the truth,” stated a transport expert. “Buyers are being misled into thinking that by purchasing a PHEV, they are benefiting the environment and saving money. In reality, PHEVs are only slightly improved than standard gas and diesel cars in terms of energy consumption, CO₂ emissions, and running expenses.”

Policy Discussion and Automotive Pressure

Hybrid vehicles have lately been drawn again into political discussions as automakers have pressed the EU to relax CO₂ targets. A planned prohibition on new combustion engine cars in 2035 has faced heavy pressure from the automotive sector and resistance from member states with large automotive manufacturing.

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

One independent energy economics specialist, who was not involved with the research, called the report a “highly valuable contribution” after a long period in which parts of the automotive industry argued there was insufficient data to accurately assess actual CO2 output.

“The results show, beyond any doubt, that the gap in lab and actual PHEV fuel consumption and CO₂ emissions is much, much greater than for gasoline or diesel vehicles,” they stated. “Any policy adjustments regarding PHEVs should be implemented with utmost caution and in the light of this data.”