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PHEVs produce nearly five times more planet-heating pollution than official figures show, according to a new analysis.

Growing Gap In Official and Actual CO2 Output

Statistics reveals that PHEVs emit only 19% less CO₂ than conventional gas and diesel cars, according to research conducted by a advocacy organization. This contrasts significantly with laboratory tests, which assumed a 75% decrease in emissions.

Analysts examined information from in-vehicle energy use meters of eight hundred thousand cars sold in the EU from 2021 and 2023. The team found that actual CO₂ emissions from PHEVs in 2023 were nearly five times higher than official figures, up from 3.5 times in 2021.

“Real-world emissions are increasing, while lab-reported figures are falling,” stated a senior analyst participating in the report. “That discrepancy is growing and creates a significant issue. As a result, PHEVs emit almost as much as gasoline vehicles.”

Key Reasons Driving the Emissions Gap

Analysts linked most of the gap to overestimates of the “electric driving share” – the percentage of kilometers travelled in electric power compared to overall distance. The team found that just 27% of travel was completed in EV mode, while lab estimates assumed over four-fifths.

Even, when running in EV mode, pollution levels were significantly higher than official estimates. That occurred because EV motors were insufficiently powerful enough to operate independently, resulting to combustion motors burning gasoline for nearly one-third of the distance covered in EV mode.

Policy and Financial Implications

Based on estimates, the underestimation of PHEV CO2 output enabled four major carmaker groups to avoid over €5bn in penalties from 2021 and 2023, by artificially simplifying adherence with European Union fleet-average CO₂ targets.

Furthermore, drivers of PHEVs would pay approximately €500 extra annually in running costs than is estimated under lab conditions.

“The bold claims that manufacturers like to make about their PHEV cars are obviously way off the truth,” commented a transport analyst. “Consumers are being misled into thinking that by buying a PHEV, they are helping the environment and cutting money. Actually, PHEVs are little better than standard petrol and diesel vehicles in terms of fuel consumption, CO₂ production, and operating costs.”

Policy Debate and Industry Pressure

Plug-in hybrid cars have lately been drawn again into policy debates as automakers have lobbied the European Union to relax CO₂ standards. A planned prohibition on new combustion engine cars in 2035 has faced heavy pressure from the automotive sector and opposition from member states with significant automotive industries.

Several high-level officials have suggested PHEVs as a potential “flexibility” solution to introduce in the regulation.

One independent energy economics expert, who was not involved with the research, called the analysis a “highly valuable contribution” after years in which segments of the car industry claimed there was too little data to accurately evaluate real-world CO2 output.

“The results demonstrate, beyond any doubt, that the gap in official and real-world PHEV energy use and CO₂ emissions is much, much larger than for gasoline or conventional cars,” they said. “Any policy adjustments regarding PHEVs should be made with extreme caution and considering this data.”