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PHEVs emit nearly 5x more planet-heating emissions than official figures show, as per a new analysis.

Growing Gap In Lab and Actual CO2 Output

Statistics reveals that PHEVs emit only one-fifth less CO₂ than conventional gas and diesel cars, based on research carried out by a advocacy group. This differs sharply with lab estimates, which suggested a three-quarters reduction in pollution.

Analysts studied information from onboard energy use meters of 800,000 vehicles sold in the EU from 2021 and 2023. They found that real-world CO₂ output from PHEVs in 2023 were nearly five times greater than official figures, increased from three and a half times in 2021.

“Actual emissions are increasing, while official figures are decreasing,” said a senior analyst participating in the report. “That gap is growing and poses a serious problem. As a result, PHEVs emit nearly as much as petrol vehicles.”

Primary Factors Driving the Emissions Gap

Analysts linked most of the difference to overestimates of the “electric driving share” – the ratio of miles driven in electric mode relative to total mileage. The team determined that just a quarter of travel was completed in EV mode, whereas official assumptions assumed 84%.

Additionally, when running in electric mode, pollution amounts were significantly higher than lab estimates. This occurred because electric motors were insufficiently powerful sufficient to function independently, leading to engines burning fossil fuels for nearly a third of the distance covered in EV mode.

Policy and Financial Consequences

Based on calculations, the underestimation of PHEV emissions enabled several major automaker companies to escape more than €5bn in fines between 2021 and 2023, by falsely simplifying compliance with European Union fleet-average CO₂ targets.

Additionally, drivers of PHEVs would spend approximately €500 more annually in running expenses than would be assumed under laboratory conditions.

“The bold claims that automakers often promote about their PHEV vehicles are clearly way off the truth,” stated a automotive expert. “Consumers are being misled into believing that by buying a PHEV, they are helping the planet and saving costs. In reality, PHEVs are little better than standard gas and diesel vehicles in terms of fuel use, CO₂ emissions, and operating expenses.”

Political Debate and Automotive Pressure

Hybrid vehicles have recently been drawn back into policy discussions as carmakers have pressed the EU to relax CO₂ standards. A planned ban on sales of new combustion engine vehicles in 2035 has faced intense pressure from the car sector and resistance from member states with large car industries.

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

An independent energy policy expert, who was unaffiliated with the study, described the analysis a “very useful addition” after a long period in which parts of the automotive industry claimed there was too little data to accurately evaluate actual CO2 output.

“The results demonstrate, without question, that the difference in lab and actual PHEV energy use and CO₂ output is much, much larger than for petrol or diesel cars,” the expert stated. “All policy adjustments concerning PHEVs should be implemented with utmost care and in the light of that data.”