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PHEVs produce almost five times greater planet-heating pollution than lab-reported figures indicate, as per a new report.

Widening Discrepancy Between Lab and Real-World CO2 Output

Data shows that PHEVs emit just one-fifth lower CO₂ than conventional gas and diesel vehicles, based on analysis carried out by a advocacy organization. That differs significantly with lab estimates, which assumed a three-quarters reduction in emissions.

Analysts examined information from onboard fuel consumption monitors of 800,000 cars sold in Europe from 2021 and 2023. They found that real-world CO₂ output from PHEVs in 2023 were 4.9 times greater than official estimates, up from 3.5 times in 2021.

“Actual CO2 output are increasing, while lab-reported emissions are falling,” stated a lead analyst participating in the study. “This gap is widening and poses a significant problem. Consequently, PHEVs pollute almost as much as petrol vehicles.”

Key Reasons Behind the Emissions Gap

Researchers linked the majority of the difference to inflated estimates of the “utility factor” – the percentage of kilometers driven in electric power relative to total mileage. The team found that just 27% of driving was completed in electric mode, while official assumptions assumed 84%.

Even, when running in electric mode, pollution amounts were significantly higher than official estimates. That happened because electric motors were insufficiently powerful sufficient to function independently, leading to combustion motors burning fossil fuels for almost one-third of the travel covered in electric mode.

Regulatory and Economic Implications

According to calculations, the lowballing of PHEV CO2 output enabled several large automaker groups to escape more than €5bn in penalties between 2021 and 2023, by artificially easing compliance with European Union fleet-average CO₂ targets.

Furthermore, owners of PHEVs would spend about €500 more per year in operating expenses than would be assumed under lab tests.

“The bold statements that automakers like to make about their plug-in hybrid vehicles are clearly way off the truth,” stated a automotive expert. “Buyers are being misled 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 vehicles in terms of fuel consumption, CO₂ production, and operating expenses.”

Political Discussion and Industry Pressure

Hybrid cars have lately been brought back into policy debates as carmakers have lobbied the EU to weaken CO₂ standards. A planned ban on new combustion engine vehicles in 2035 has faced heavy lobbying from the car industry and opposition from member states with large automotive industries.

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

One external energy economics expert, who was unaffiliated with the research, described the report a “very useful addition” after years in which segments of the car sector claimed there was insufficient information to accurately assess actual emissions.

“The results demonstrate, beyond any doubt, that the difference in lab and actual PHEV fuel consumption and CO₂ output is significantly greater than for gasoline or diesel cars,” the expert said. “Any regulatory adjustments regarding PHEVs should be made with utmost caution and in the light of this evidence.”