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Plug-in hybrid cars emit almost five times greater global warming emissions than lab-reported data show, as per a recent report.

Widening Gap Between Lab and Real-World CO2 Output

Statistics shows that PHEVs emit only 19% lower CO₂ than traditional gas and diesel vehicles, based on research conducted by a non-profit organization. This differs significantly with lab tests, which suggested a 75% reduction in pollution.

Analysts examined data from in-vehicle energy use meters of 800,000 cars registered in Europe from 2021 and 2023. The team discovered that real-world CO₂ emissions from PHEVs in 2023 were nearly five times higher than official figures, up from 3.5 times in 2021.

“Actual emissions are rising, while lab-reported figures are falling,” said a senior analyst involved in the report. “This discrepancy is growing and creates a significant issue. Consequently, PHEVs pollute almost as much as gasoline vehicles.”

Primary Reasons Driving the Discrepancy

Researchers attributed most of the difference to inflated estimates of the “utility factor” – the percentage of kilometers driven in electric power relative to overall mileage. The team found that only 27% of travel was completed in electric mode, while official estimates suggested over four-fifths.

Even, when running in electric mode, pollution amounts were significantly higher than lab estimates. That happened because EV motors were not strong sufficient to function alone, resulting to engines burning fossil fuels for nearly one-third of the travel covered in electric mode.

Regulatory and Financial Consequences

Based on calculations, the lowballing of PHEV emissions enabled four major carmaker groups to avoid over €5bn in penalties from 2021 and 2023, by artificially simplifying adherence with EU average fleet CO₂ targets.

Additionally, owners of PHEVs could pay about €500 extra annually in operating costs than would be estimated under lab tests.

“The bold statements that automakers often promote about their PHEV cars are clearly far from the mark,” stated a transport expert. “Buyers are being duped into thinking that by buying a PHEV, they are benefiting the planet and saving costs. Actually, PHEVs are little better than regular petrol and diesel vehicles in terms of fuel consumption, CO₂ production, and running expenses.”

Political Discussion and Industry Lobbying

Plug-in hybrid vehicles have lately been drawn back into political debates as automakers have lobbied the European Union to weaken CO₂ standards. A proposed ban on sales of new combustion engine cars in 2035 has faced heavy pressure from the car sector and opposition from member states with large automotive industries.

Several high-level politicians have suggested PHEVs as a potential “compromise” option to include in the regulation.

An external energy economics expert, who was not involved with the study, described the analysis a “very useful contribution” after years in which parts of the automotive industry claimed there was too little data to accurately assess actual CO2 output.

“These findings show, without question, that the difference in official and real-world PHEV fuel consumption and CO₂ output is significantly larger than for gasoline or diesel vehicles,” they said. “All regulatory adjustments regarding PHEVs should be made with utmost care and considering this data.”