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

Widening Gap Between Official and Actual CO2 Output

Statistics reveals that PHEVs emit just one-fifth lower CO₂ than traditional gas and diesel vehicles, based on analysis carried out by a advocacy group. This differs sharply with lab estimates, which suggested a 75% reduction in emissions.

Analysts studied information from onboard energy use monitors of eight hundred thousand cars sold in the EU from 2021 and 2023. They discovered that real-world CO₂ emissions from PHEVs in 2023 were 4.9 times greater than official estimates, 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. “That discrepancy is growing and poses a serious problem. Consequently, PHEVs emit almost as much as petrol cars.”

Key Reasons Driving the Discrepancy

Researchers linked the majority of the gap to overestimates of the “electric driving share” – the percentage of kilometers driven in electric mode compared to overall mileage. They determined that just 27% of travel was done in electric mode, while official estimates suggested 84%.

Even, when operating in electric mode, pollution levels were significantly higher than lab projections. This happened because electric motors were not strong sufficient to operate alone, leading to engines using gasoline for almost a third of the travel completed in electric mode.

Policy and Financial Consequences

According to calculations, the underestimation of PHEV emissions enabled four large automaker groups to avoid more than €5bn in fines between 2021 and 2023, by artificially easing adherence with European Union average fleet CO₂ standards.

Additionally, drivers of PHEVs would pay approximately €500 more per year in operating costs than is estimated under lab conditions.

“The strong statements that automakers often promote about their PHEV vehicles are obviously way off the mark,” stated a automotive analyst. “Consumers are being misled into thinking that by buying a PHEV, they are benefiting the environment and saving costs. In reality, PHEVs are little better than standard gas and diesel vehicles in terms of energy use, CO₂ production, and operating expenses.”

Political Debate and Automotive Pressure

Hybrid cars have lately been brought again into policy debates as carmakers have lobbied the European Union to relax CO₂ standards. A proposed ban on sales of new internal combustion vehicles in 2035 has faced heavy lobbying from the automotive industry and resistance from EU countries with large automotive manufacturing.

Some senior officials have suggested plug-in hybrids as a potential “compromise” option to introduce in the regulation.

An independent energy economics specialist, who was unaffiliated with the research, described the report a “very useful contribution” after a long period in which segments of the car industry argued there was too little information to accurately evaluate actual CO2 output.

“The results show, beyond any doubt, that the gap between lab and actual PHEV energy use and CO₂ emissions is much, much larger than for petrol or conventional vehicles,” the expert stated. “Any policy adjustments concerning PHEVs should be made with extreme caution and in the light of this data.”