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PHEVs release nearly 5x more global warming pollution than official data show, as per a recent report.

Growing Discrepancy Between Lab and Actual CO2 Output

Data shows that PHEVs release just one-fifth lower CO₂ than conventional gas and diesel vehicles, according to analysis conducted by a non-profit organization. That differs significantly with laboratory estimates, which suggested a 75% decrease in emissions.

Researchers examined information from onboard fuel consumption monitors of 800,000 cars registered in Europe from 2021 and 2023. The team discovered that actual CO₂ output from PHEVs in 2023 were 4.9 times higher than official figures, increased from 3.5 times in 2021.

“Actual emissions are rising, while lab-reported figures are decreasing,” stated a lead researcher participating in the report. “That discrepancy is widening and poses a significant issue. As a result, PHEVs emit nearly as much as petrol vehicles.”

Key Factors Behind the Discrepancy

Analysts linked most of the gap to inflated estimates of the “electric driving share” – the percentage of miles travelled in electric power compared to total distance. They found that just a quarter of driving was completed in electric mode, while lab assumptions assumed 84%.

Additionally, when running in electric mode, pollution levels were significantly higher than official estimates. This occurred because electric motors were not strong sufficient to function alone, resulting to combustion motors burning gasoline for nearly a third of the distance completed in EV mode.

Policy and Economic Implications

According to estimates, the lowballing of PHEV CO2 output enabled four large automaker companies to escape over €5bn in penalties between 2021 and 2023, by falsely easing compliance with EU average fleet CO₂ targets.

Furthermore, owners of PHEVs could pay about €500 more annually in operating costs than would be estimated under laboratory tests.

“The bold statements that automakers often promote about their PHEV vehicles are clearly far from the truth,” stated a transport expert. “Consumers are being misled into believing that by purchasing a PHEV, they are benefiting the environment and saving money. Actually, PHEVs are only slightly improved than standard petrol and diesel cars in terms of energy consumption, CO₂ production, and running costs.”

Political Debate and Industry Pressure

Hybrid vehicles have lately been drawn back into political debates as automakers have pressed the European Union to relax CO₂ targets. A planned ban on new combustion engine cars in 2035 has faced intense pressure from the car industry and resistance from member states with significant car industries.

Several high-level officials have suggested plug-in hybrids as a potential “flexibility” option to include in the regulation.

One external energy policy expert, who was not involved with the study, called the report a “very useful contribution” after a long period in which segments of the automotive industry claimed there was too little data to properly evaluate real-world CO2 output.

“These findings demonstrate, beyond any doubt, that the gap in official and actual PHEV fuel consumption and CO₂ output is much, much larger than for gasoline or conventional vehicles,” they said. “All policy changes regarding PHEVs should be made with extreme caution and considering this data.”