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Plug-in hybrid cars release almost 5x more planet-heating pollution than official data show, as per a recent report.

Growing Discrepancy Between Lab and Actual CO2 Output

Statistics shows that PHEVs release only one-fifth less CO₂ than traditional gas and diesel cars, according to research conducted by a advocacy group. That differs sharply with lab tests, which assumed a three-quarters reduction in emissions.

Analysts studied information from onboard fuel consumption meters of eight hundred thousand cars sold in Europe between 2021 and 2023. The team discovered that actual CO₂ output from PHEVs in 2023 were 4.9 times greater than lab figures, up from three and a half times in 2021.

“Real-world emissions are increasing, while official emissions are falling,” stated a senior researcher participating in the report. “This gap is growing and poses a serious issue. Consequently, PHEVs pollute nearly as much as petrol cars.”

Primary Factors Driving the Discrepancy

Analysts attributed the majority of the difference to overestimates of the “electric driving share” – the percentage of miles driven in battery mode compared to total distance. The team determined that only a quarter of driving was done in EV mode, whereas official assumptions suggested over four-fifths.

Additionally, when running in EV mode, pollution amounts were well above lab estimates. This occurred because EV motors were not strong sufficient to operate alone, resulting to combustion motors burning gasoline for almost a third of the travel completed in electric mode.

Policy and Economic Consequences

Based on estimates, the underestimation of PHEV CO2 output enabled four large carmaker groups to avoid over €5bn in fines from 2021 and 2023, by artificially easing compliance with European Union fleet-average CO₂ standards.

Additionally, drivers of PHEVs would spend about €500 extra per year in operating expenses than is assumed under laboratory conditions.

“The bold claims that automakers like to make about their plug-in hybrid cars are obviously way off the mark,” commented a automotive analyst. “Consumers are being duped into thinking that by purchasing a PHEV, they are benefiting the environment and saving costs. In reality, PHEVs are little better than regular gas and diesel vehicles in terms of fuel use, CO₂ production, and running expenses.”

Political Debate and Industry Pressure

Hybrid cars have recently been brought back into political discussions as automakers have pressed the European Union to relax CO₂ targets. A planned ban on sales of new internal combustion cars in 2035 has faced heavy lobbying from the automotive sector and opposition from EU countries with large automotive manufacturing.

Some high-level politicians have proposed PHEVs as a potential “compromise” option to introduce in the legislation.

An external energy policy expert, who was not involved with the study, described the analysis a “very useful contribution” after years in which parts of the car industry claimed there was insufficient information to accurately assess real-world emissions.

“These findings show, without question, that the gap in lab and actual PHEV energy use and CO₂ output is much, much larger than for gasoline or diesel cars,” the expert said. “Any policy changes regarding PHEVs should be implemented with utmost care and in the light of that data.”