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PHEVs produce nearly 5x greater planet-heating emissions than lab-reported data show, as per a new report.

Growing Gap In Official and Real-World CO2 Output

Statistics reveals that PHEVs emit only one-fifth lower CO₂ than traditional petrol and diesel cars, according to research carried out by a advocacy group. This differs significantly with laboratory estimates, which assumed a three-quarters decrease in emissions.

Analysts studied information from in-vehicle energy use meters of 800,000 vehicles registered in Europe between 2021 and 2023. The team discovered that real-world CO₂ emissions from PHEVs in 2023 were nearly five times greater than official estimates, increased from 3.5 times in 2021.

“Real-world CO2 output are increasing, while official figures are falling,” said a lead analyst participating in the report. “That gap is widening and creates a significant problem. As a result, PHEVs pollute nearly as heavily as gasoline cars.”

Key Reasons Behind the Emissions Gap

Analysts linked 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 a quarter of travel was completed in electric mode, while official estimates assumed 84%.

Even, when running in electric mode, pollution amounts were well above lab estimates. This occurred because electric motors were insufficiently powerful sufficient to operate independently, leading to combustion motors burning gasoline for nearly a third of the distance covered in electric mode.

Regulatory and Economic Consequences

Based on estimates, the underestimation of PHEV emissions allowed several major carmaker groups to escape more than €5bn in penalties from 2021 and 2023, by falsely easing adherence with EU fleet-average CO₂ targets.

Additionally, drivers of PHEVs would spend approximately €500 more annually in operating costs than would be assumed under lab conditions.

“The bold statements that automakers like to make about their PHEV vehicles are obviously far from the truth,” stated a automotive expert. “Buyers are being duped into believing that by buying a PHEV, they are benefiting the planet and saving costs. In reality, PHEVs are only slightly better than standard petrol and diesel cars in terms of fuel use, CO₂ production, and operating expenses.”

Policy Debate and Automotive Lobbying

Plug-in hybrid cars have lately been brought again into political discussions as carmakers have lobbied the EU to weaken CO₂ targets. A proposed ban on new internal combustion cars in 2035 has faced intense pressure from the car industry and opposition from EU countries with significant car industries.

Some high-level officials have proposed plug-in hybrids as a potential “flexibility” solution to include in the legislation.

One external energy policy specialist, who was not involved with the study, described the analysis a “very useful contribution” after a long period in which parts of the automotive sector argued there was too little data to accurately assess actual CO2 output.

“These findings demonstrate, without question, that the difference in lab and actual PHEV fuel consumption and CO₂ output is significantly larger than for gasoline or diesel cars,” they said. “Any policy changes concerning PHEVs should be made with extreme care and in the light of this data.”