🔗 Share this article

Plug-in hybrid electric vehicles produce nearly 5x greater global warming pollution than lab-reported figures indicate, according to a recent analysis.

Growing Discrepancy Between Lab and Actual Emissions

Statistics reveals that PHEVs release only one-fifth less CO₂ than traditional gas and diesel vehicles, based on research carried out by a non-profit organization. That contrasts sharply with laboratory estimates, which assumed a 75% decrease in pollution.

Researchers examined information from in-vehicle energy use monitors of 800,000 cars registered in Europe between 2021 and 2023. The team found that actual CO₂ emissions from PHEVs in 2023 were 4.9 times higher than official estimates, up from three and a half times in 2021.

“Actual emissions are increasing, while lab-reported figures are decreasing,” said a senior analyst involved in the study. “This gap is growing and poses a serious problem. Consequently, PHEVs pollute nearly as much as gasoline cars.”

Primary Factors Behind the Emissions Gap

Analysts linked most of the gap to overestimates of the “utility factor” – the percentage of miles driven in electric mode relative to total mileage. The team found that only a quarter of travel was completed in EV mode, whereas official assumptions assumed over four-fifths.

Additionally, when operating in EV mode, pollution amounts were significantly higher than official projections. That occurred because electric motors were not strong sufficient to function independently, resulting to combustion motors burning gasoline for nearly one-third of the travel completed in electric mode.

Regulatory and Economic Implications

According to calculations, the lowballing of PHEV CO2 output allowed several large carmaker companies to avoid over €5bn in fines between 2021 and 2023, by artificially simplifying adherence with EU fleet-average CO₂ targets.

Furthermore, owners of PHEVs could pay about €500 more annually in operating costs than is estimated under lab conditions.

“The bold claims that automakers often promote about their PHEV vehicles are obviously way off the mark,” commented a automotive expert. “Consumers are being duped into thinking that by purchasing a PHEV, they are helping the environment and saving costs. Actually, PHEVs are little better than regular petrol and diesel cars in terms of fuel use, CO₂ production, and running costs.”

Policy Debate and Automotive Pressure

Hybrid vehicles have lately been brought back into policy discussions as carmakers have lobbied the EU to relax CO₂ standards. A proposed ban on new internal combustion cars in 2035 has faced heavy pressure from the car industry and opposition from EU countries with significant automotive industries.

Several senior officials have suggested plug-in hybrids as a possible “flexibility” solution to introduce in the legislation.

One independent energy policy specialist, who was not involved with the research, called the report a “very useful addition” after a long period in which segments of the automotive industry claimed there was too little information to accurately assess real-world CO2 output.

“The results demonstrate, beyond any doubt, that the gap between lab and actual PHEV fuel consumption and CO₂ emissions is much, much greater than for gasoline or diesel cars,” the expert said. “Any regulatory adjustments concerning PHEVs should be implemented with utmost care and considering that evidence.”