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PHEVs produce nearly 5x more global warming emissions than official data show, as per a recent analysis.

Growing Discrepancy Between Lab and Actual CO2 Output

Statistics shows that PHEVs release only one-fifth lower CO₂ than traditional gas and diesel cars, based on analysis carried out by a non-profit group. That contrasts sharply with lab tests, which assumed a 75% reduction in emissions.

Analysts studied information from in-vehicle energy use monitors of 800,000 vehicles sold in the EU from 2021 and 2023. The team discovered that real-world CO₂ output from PHEVs in 2023 were nearly five times greater than official estimates, up from three and a half times in 2021.

“Actual emissions are increasing, while lab-reported figures are falling,” stated a senior analyst participating in the report. “This discrepancy is growing and poses a significant problem. As a result, PHEVs pollute nearly as much as petrol vehicles.”

Primary Factors Driving the Emissions Gap

Analysts linked the majority of the difference to inflated estimates of the “utility factor” – the percentage of miles travelled in electric power relative to total distance. They found that only 27% of travel was done in EV mode, while official estimates assumed over four-fifths.

Additionally, when operating in EV mode, pollution amounts were significantly higher than official projections. That happened because EV motors were insufficiently powerful sufficient to function independently, leading to combustion motors burning gasoline for nearly one-third of the distance covered in EV mode.

Policy and Financial Consequences

Based on estimates, the underestimation of PHEV emissions enabled four large automaker groups to escape more than €5bn in fines between 2021 and 2023, by artificially simplifying adherence with European Union fleet-average CO₂ standards.

Additionally, owners of PHEVs would spend about €500 extra annually in running costs than is estimated under lab tests.

“The strong claims that automakers often promote about their PHEV cars are clearly far from the truth,” stated a transport expert. “Buyers are being misled into thinking that by buying a PHEV, they are helping the environment and saving money. In reality, PHEVs are little improved than regular gas and diesel cars in terms of fuel consumption, CO₂ emissions, and running expenses.”

Policy Debate and Industry Pressure

Hybrid cars have recently been brought again into political debates as automakers have pressed the EU to weaken CO₂ standards. A proposed ban on new internal combustion vehicles in 2035 has faced intense lobbying from the automotive sector and opposition from member states with large automotive industries.

Several high-level officials have proposed PHEVs as a possible “compromise” option to include in the legislation.

An external energy policy expert, who was unaffiliated with the research, called the analysis a “very useful addition” after a long period in which segments of the automotive sector argued there was insufficient information to accurately assess actual CO2 output.

“These findings show, without question, that the gap between official and actual PHEV energy use and CO₂ output is significantly greater than for petrol or conventional cars,” the expert stated. “Any regulatory changes regarding PHEVs should be implemented with extreme caution and in the light of this evidence.”