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Plug-in hybrid cars produce almost 5x greater global warming emissions than official figures show, as per a recent report.

Growing Discrepancy Between Official and Actual CO2 Output

Data reveals that PHEVs emit only one-fifth lower CO₂ than conventional gas and diesel cars, based on research carried out by a advocacy organization. This contrasts sharply with laboratory estimates, which suggested a 75% reduction in pollution.

Researchers studied information from onboard energy use meters of eight hundred thousand cars sold in Europe from 2021 and 2023. The team found that actual CO₂ emissions from PHEVs in 2023 were 4.9 times higher than lab figures, up from three and a half times in 2021.

“Actual CO2 output are rising, while official emissions are decreasing,” said a lead researcher participating in the report. “That gap is growing and poses a serious issue. As a result, PHEVs emit nearly as much as gasoline cars.”

Primary Reasons Driving the Discrepancy

Researchers linked most of the difference to inflated estimates of the “electric driving share” – the ratio of miles travelled in electric mode relative to overall mileage. The team determined that just a quarter of driving was done in electric mode, whereas lab estimates assumed over four-fifths.

Even, when operating in electric mode, pollution amounts were significantly higher than official estimates. This happened because electric motors were not strong enough to function alone, resulting to combustion motors using fossil fuels for almost a third of the distance completed in electric mode.

Regulatory and Financial Implications

Based on estimates, the underestimation of PHEV emissions allowed four large carmaker groups to avoid over €5bn in fines between 2021 and 2023, by artificially easing compliance with EU fleet-average CO₂ targets.

Additionally, owners of PHEVs would spend approximately €500 more annually in running expenses than would be estimated under laboratory conditions.

“The strong claims that manufacturers often promote about their plug-in hybrid vehicles are obviously way off the mark,” commented a automotive expert. “Consumers are being duped into thinking that by purchasing a PHEV, they are benefiting the planet and cutting costs. In reality, PHEVs are little improved than standard gas and diesel vehicles in terms of energy consumption, CO₂ production, and operating expenses.”

Political Discussion and Automotive Lobbying

Hybrid vehicles have recently been drawn back into policy discussions as carmakers have pressed the EU to weaken CO₂ standards. A planned prohibition on new internal combustion cars in 2035 has faced heavy lobbying from the car sector and opposition from EU countries with significant automotive manufacturing.

Several senior politicians have proposed plug-in hybrids as a potential “flexibility” solution to include in the regulation.

One independent energy economics expert, who was unaffiliated with the research, called the analysis a “very useful addition” after years in which segments of the automotive industry claimed there was insufficient data to properly assess real-world CO2 output.

“The results show, beyond any doubt, that the difference in lab and actual PHEV fuel consumption and CO₂ emissions is much, much larger than for gasoline or diesel cars,” the expert said. “Any regulatory adjustments regarding PHEVs should be made with extreme caution and in the light of this data.”