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PHEVs produce almost 5x more planet-heating pollution than lab-reported figures show, according to a recent analysis.

Widening Gap In Official and Real-World CO2 Output

Data shows that PHEVs release only one-fifth lower CO₂ than traditional petrol and diesel vehicles, based on analysis conducted by a advocacy organization. This contrasts sharply with laboratory estimates, which assumed a 75% reduction in emissions.

Researchers examined data from onboard energy use meters of 800,000 cars registered in Europe between 2021 and 2023. The team discovered that real-world CO₂ emissions from PHEVs in 2023 were 4.9 times greater than official estimates, increased from 3.5 times in 2021.

“Real-world emissions are increasing, while lab-reported figures are decreasing,” stated a lead researcher participating in the report. “This discrepancy is growing and creates a significant issue. As a result, PHEVs emit almost as heavily as petrol cars.”

Primary Factors Behind the Emissions Gap

Analysts attributed the majority of the gap to overestimates of the “electric driving share” – the ratio of miles travelled in battery power compared to overall distance. The team found that just 27% of travel was done in EV mode, whereas lab assumptions assumed over four-fifths.

Even, when running in EV mode, emission amounts were well above official estimates. This happened because EV motors were insufficiently powerful enough to operate independently, leading to engines burning gasoline for nearly one-third of the distance completed in electric mode.

Policy and Financial Implications

According to calculations, the lowballing of PHEV emissions enabled several large carmaker companies to avoid more than €5bn in penalties from 2021 and 2023, by artificially simplifying compliance with EU fleet-average CO₂ targets.

Additionally, drivers of PHEVs could pay approximately €500 extra annually in operating expenses than would be assumed under laboratory conditions.

“The bold claims that manufacturers often promote about their PHEV vehicles are clearly way off the mark,” stated a transport analyst. “Consumers are being misled into believing that by buying a PHEV, they are benefiting the planet and saving costs. Actually, PHEVs are little improved than standard petrol and diesel vehicles in terms of energy consumption, CO₂ production, and operating costs.”

Political Discussion and Automotive Lobbying

Hybrid cars have recently been brought back into political debates as automakers have lobbied the EU to relax CO₂ standards. A planned ban on new combustion engine vehicles in 2035 has faced heavy pressure from the automotive industry and resistance from EU countries with large automotive manufacturing.

Several senior officials have suggested PHEVs as a possible “flexibility” option to introduce in the regulation.

An independent energy policy expert, who was not involved with the research, described the report a “highly valuable contribution” after a long period in which parts of the automotive sector argued there was too little information to accurately assess actual CO2 output.

“The results demonstrate, beyond any doubt, that the difference in lab and actual PHEV energy use and CO₂ output is significantly larger than for petrol or conventional cars,” they stated. “All policy changes regarding PHEVs should be made with extreme caution and in the light of this evidence.”