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PHEVs produce nearly 5x more global warming pollution than lab-reported figures show, as per a recent report.

Growing Gap In Official and Real-World CO2 Output

Statistics reveals that PHEVs emit only one-fifth lower CO₂ than conventional petrol and diesel cars, according to analysis carried out by a non-profit organization. That differs significantly with laboratory estimates, which suggested a three-quarters decrease in pollution.

Analysts studied information from onboard energy use monitors of eight hundred thousand cars registered in the EU between 2021 and 2023. The team found that real-world CO₂ emissions from PHEVs in 2023 were nearly five times higher than official figures, increased from three and a half times in 2021.

“Actual CO2 output are rising, while official figures are falling,” said a lead researcher involved in the study. “This discrepancy is widening and poses a significant problem. Consequently, PHEVs emit nearly as much as gasoline cars.”

Key Factors Driving the Emissions Gap

Researchers attributed most of the difference to overestimates of the “electric driving share” – the percentage of kilometers driven in battery power relative to overall mileage. The team determined that only 27% of driving was completed in EV mode, whereas lab assumptions assumed over four-fifths.

Additionally, when operating in electric mode, emission amounts were significantly higher than lab estimates. That happened because EV motors were not strong sufficient to function alone, leading to engines using fossil fuels for almost a third of the travel covered in electric mode.

Regulatory and Economic Implications

According to calculations, the lowballing of PHEV emissions allowed four large automaker groups to avoid over €5bn in fines from 2021 and 2023, by artificially simplifying compliance with EU average fleet CO₂ standards.

Furthermore, drivers of PHEVs could pay approximately €500 more annually in running costs than is estimated under laboratory tests.

“The strong statements that manufacturers like to make about their plug-in hybrid vehicles are obviously way off the truth,” stated a automotive analyst. “Consumers are being misled into thinking that by purchasing a PHEV, they are helping the planet and saving money. In reality, PHEVs are only slightly better than standard petrol and diesel cars in terms of fuel consumption, CO₂ production, and running costs.”

Policy Debate and Industry Pressure

Plug-in hybrid cars have recently been brought back into policy debates as carmakers have lobbied the European Union to relax CO₂ targets. A proposed ban on new internal combustion vehicles in 2035 has faced heavy pressure from the automotive industry and resistance from member states with significant automotive manufacturing.

Some high-level politicians have proposed plug-in hybrids as a possible “flexibility” solution to include in the regulation.

One external energy economics expert, who was not involved with the study, described the analysis a “highly valuable addition” after years in which parts of the car industry argued there was insufficient information to accurately evaluate real-world CO2 output.

“The results show, beyond any doubt, that the gap in official and real-world PHEV fuel consumption and CO₂ output is much, much greater than for gasoline or conventional vehicles,” they said. “All policy changes regarding PHEVs should be implemented with utmost care and in the light of that evidence.”