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Plug-in hybrid cars release nearly five times greater global warming emissions than official figures show, according to a new report.

Growing Discrepancy In Official and Actual CO2 Output

Statistics reveals that PHEVs release only one-fifth lower CO₂ than conventional petrol and diesel vehicles, based on research carried out by a non-profit group. This differs sharply with lab estimates, which suggested a 75% decrease in pollution.

Researchers studied information from onboard fuel consumption monitors of 800,000 cars sold in the EU between 2021 and 2023. The team found that actual CO₂ emissions from PHEVs in 2023 were nearly five times higher than official figures, up from three and a half times in 2021.

“Actual CO2 output are rising, while official figures are falling,” said a senior analyst participating in the study. “That gap is widening and creates a serious issue. As a result, PHEVs pollute almost as heavily as gasoline vehicles.”

Primary Reasons Behind the Emissions Gap

Analysts linked the majority of the difference to inflated estimates of the “utility factor” – the percentage of kilometers driven in electric power relative to total mileage. They determined that only a quarter of travel was done in EV mode, while lab assumptions assumed 84%.

Additionally, when running in electric mode, emission amounts were well above official estimates. This happened because electric motors were insufficiently powerful enough to operate independently, resulting to combustion motors using gasoline for almost a third of the travel completed in EV mode.

Regulatory and Financial Implications

According to calculations, the underestimation of PHEV CO2 output enabled several major automaker groups to escape over €5bn in penalties from 2021 and 2023, by artificially easing adherence with European Union average fleet CO₂ targets.

Furthermore, drivers of PHEVs would spend approximately €500 extra annually in operating costs than is assumed under laboratory conditions.

“The bold claims that manufacturers often promote about their plug-in hybrid cars are clearly far from the truth,” commented a automotive expert. “Consumers are being misled into thinking that by buying a PHEV, they are helping the planet and saving money. Actually, PHEVs are only slightly better than regular gas and diesel vehicles in terms of fuel consumption, CO₂ emissions, and operating costs.”

Policy Discussion and Industry Pressure

Hybrid cars have lately been brought again into policy discussions as automakers have lobbied the EU to weaken CO₂ targets. A proposed prohibition on sales of new internal combustion cars in 2035 has faced heavy pressure from the automotive sector and resistance from EU countries with large car industries.

Several high-level politicians have proposed plug-in hybrids as a possible “compromise” option to include in the regulation.

One external energy economics specialist, who was not involved with the study, called the analysis a “very useful contribution” after years in which segments of the automotive industry claimed there was insufficient data to accurately assess real-world CO2 output.

“These findings show, without question, that the gap between lab and actual PHEV energy use and CO₂ output is significantly larger than for petrol or diesel vehicles,” the expert said. “Any regulatory adjustments regarding PHEVs should be made with extreme caution and in the light of this data.”