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PHEVs emit almost five times greater planet-heating pollution than official figures indicate, as per a new report.

Growing Discrepancy In Official and Actual CO2 Output

Data reveals that PHEVs release only 19% lower CO₂ than traditional petrol and diesel cars, based on analysis conducted by a advocacy organization. That differs sharply with lab estimates, which assumed a three-quarters decrease in emissions.

Researchers examined data from in-vehicle energy use meters of eight hundred thousand cars registered in the EU between 2021 and 2023. The team discovered that real-world CO₂ output from PHEVs in 2023 were nearly five times greater than official figures, up from 3.5 times in 2021.

“Actual CO2 output are rising, while lab-reported figures are falling,” said a senior researcher involved in the study. “This discrepancy is widening and creates a significant issue. Consequently, PHEVs emit nearly as much as petrol vehicles.”

Key Reasons Driving the Emissions Gap

Analysts linked the majority of the difference to overestimates of the “electric driving share” – the ratio of miles driven in electric mode compared to total mileage. The team found that only a quarter of travel was done in electric mode, while official estimates suggested over four-fifths.

Additionally, when running in electric mode, emission amounts were well above official projections. That happened because electric motors were insufficiently powerful sufficient to operate independently, leading to combustion motors burning gasoline for nearly a third of the travel completed in electric mode.

Policy and Financial Consequences

Based on estimates, the underestimation of PHEV emissions allowed four major carmaker groups to escape over €5bn in penalties between 2021 and 2023, by artificially simplifying adherence with European Union average fleet CO₂ standards.

Additionally, drivers of PHEVs could pay approximately €500 more annually in operating costs than would be estimated under laboratory conditions.

“The strong statements that automakers often promote about their PHEV cars are clearly far from the mark,” commented a automotive expert. “Consumers are being duped into thinking that by buying a PHEV, they are benefiting the environment and saving money. Actually, PHEVs are little improved than standard gas and diesel cars in terms of energy consumption, CO₂ production, and running expenses.”

Policy Discussion and Industry Pressure

Hybrid vehicles have recently been drawn back into political discussions as automakers have lobbied the European Union to weaken CO₂ targets. A planned prohibition on sales of new internal combustion vehicles in 2035 has faced heavy lobbying from the automotive industry and resistance from member states with large automotive industries.

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

An independent energy economics expert, who was not involved with the study, described the report a “highly valuable addition” after a long period in which segments of the automotive industry argued there was too little information to accurately assess actual CO2 output.

“The results show, beyond any doubt, that the gap between official and actual PHEV energy use and CO₂ emissions is significantly larger than for gasoline or conventional vehicles,” the expert stated. “Any regulatory changes concerning PHEVs should be implemented with extreme caution and considering that evidence.”