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Plug-in hybrid electric vehicles emit almost five times more global warming emissions than official data show, as per a new analysis.

Growing Gap In Official and Real-World CO2 Output

Statistics shows that PHEVs emit only one-fifth lower CO₂ than traditional gas and diesel vehicles, based on analysis carried out by a non-profit group. That contrasts sharply with lab tests, which suggested a 75% decrease in pollution.

Researchers examined information from onboard energy use monitors of 800,000 vehicles registered in the EU from 2021 and 2023. The team found that real-world CO₂ output from PHEVs in 2023 were 4.9 times greater than official estimates, up from three and a half times in 2021.

“Real-world emissions are rising, while official emissions are falling,” stated a lead researcher participating in the study. “This discrepancy is widening and poses a significant issue. As a result, PHEVs pollute nearly as much as gasoline cars.”

Key Reasons Driving the Discrepancy

Researchers linked most of the gap to inflated estimates of the “utility factor” – the percentage of kilometers travelled in battery mode compared to total mileage. They determined that just a quarter of driving was completed in EV mode, whereas lab estimates suggested 84%.

Even, when operating in electric mode, pollution levels were significantly higher than official projections. That happened because EV motors were not strong enough to operate alone, resulting to engines burning fossil fuels for almost a third of the travel completed in electric mode.

Regulatory and Financial Implications

Based on calculations, the lowballing of PHEV emissions allowed several major carmaker companies to escape over €5bn in fines between 2021 and 2023, by artificially easing adherence with EU fleet-average CO₂ targets.

Furthermore, drivers of PHEVs could spend about €500 extra annually in running expenses than would be assumed under lab tests.

“The bold claims that automakers like to make about their plug-in hybrid vehicles are obviously far from the mark,” stated a automotive analyst. “Consumers are being misled into thinking that by buying a PHEV, they are helping the planet and saving costs. In reality, PHEVs are only slightly improved than standard petrol and diesel cars in terms of energy use, CO₂ emissions, and running expenses.”

Policy Discussion and Industry Lobbying

Hybrid vehicles have recently been brought back into policy discussions as automakers have pressed the EU to weaken CO₂ standards. A planned ban on new combustion engine cars in 2035 has faced intense pressure from the automotive sector and opposition from member states with large automotive industries.

Some high-level politicians have suggested plug-in hybrids as a possible “flexibility” solution to include in the regulation.

An independent energy economics expert, who was unaffiliated with the study, described the analysis a “highly valuable addition” after years in which parts of the car sector claimed there was too little information to accurately evaluate real-world CO2 output.

“These findings show, beyond any doubt, that the gap between official and real-world PHEV energy use and CO₂ emissions is significantly greater than for gasoline or conventional cars,” they said. “All regulatory adjustments concerning PHEVs should be made with utmost caution and in the light of that evidence.”