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Plug-in hybrid cars emit nearly 5x greater global warming pollution than official data indicate, as per a recent analysis.

Growing Gap In Lab and Real-World CO2 Output

Data shows that PHEVs emit just 19% less CO₂ than conventional gas and diesel vehicles, according to analysis carried out by a non-profit organization. That differs significantly with lab estimates, which suggested a three-quarters reduction in emissions.

Analysts examined information from in-vehicle energy use monitors of 800,000 vehicles sold in the EU between 2021 and 2023. The team discovered that real-world CO₂ emissions from PHEVs in 2023 were 4.9 times greater than lab estimates, up from 3.5 times in 2021.

“Actual emissions are increasing, while official figures are decreasing,” stated a senior analyst participating in the study. “This discrepancy is growing and poses a significant issue. Consequently, PHEVs emit almost as much as petrol vehicles.”

Key Factors Driving the Emissions Gap

Analysts linked most of the difference to inflated estimates of the “utility factor” – the percentage of kilometers driven in electric power compared to total distance. They found that just a quarter of travel was completed in EV mode, while official estimates assumed over four-fifths.

Even, when operating in EV mode, pollution levels were well above lab projections. This occurred because electric motors were insufficiently powerful sufficient to function alone, leading to combustion motors using fossil fuels for almost a third of the distance completed in electric mode.

Regulatory and Economic Consequences

According to estimates, the lowballing of PHEV CO2 output allowed four major automaker companies to avoid over €5bn in penalties between 2021 and 2023, by falsely easing adherence with European Union average fleet CO₂ targets.

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

“The bold statements that automakers often promote about their plug-in hybrid vehicles are obviously way off the mark,” commented a transport expert. “Consumers are being duped into thinking that by buying a PHEV, they are helping the planet and cutting costs. In reality, PHEVs are only slightly improved than standard petrol and diesel vehicles in terms of fuel consumption, CO₂ emissions, and running expenses.”

Policy Debate and Industry Pressure

Hybrid cars have recently been brought back into policy discussions as automakers have lobbied the European Union to weaken CO₂ standards. A proposed ban on new internal combustion vehicles in 2035 has faced heavy lobbying from the car sector and opposition from EU countries with large car industries.

Some high-level officials have suggested PHEVs as a possible “compromise” solution to include in the regulation.

An external energy policy expert, who was unaffiliated with the study, described the report a “very useful contribution” after years in which parts of the automotive industry argued there was too little data to accurately assess actual emissions.

“These findings show, without question, that the difference between lab and real-world PHEV energy use and CO₂ emissions is significantly larger than for gasoline or conventional cars,” they stated. “All policy changes regarding PHEVs should be made with extreme care and considering that data.”