Plug in Hybrid electric Cars Emit Almost as Much as Petrol Cars, Report Finds

Plug-in hybrid cars emit almost 5x greater global warming emissions than official figures indicate, according to a new analysis.

Growing Discrepancy In Lab and Actual Emissions

Statistics reveals that PHEVs emit only 19% less CO₂ than conventional petrol and diesel cars, according to research carried out by a advocacy group. That differs significantly with laboratory estimates, which suggested a three-quarters reduction in pollution.

Researchers studied information from onboard fuel consumption monitors of 800,000 cars registered in Europe between 2021 and 2023. The team found that real-world CO₂ output from PHEVs in 2023 were nearly five times higher than official figures, increased from 3.5 times in 2021.

“Real-world emissions are rising, while lab-reported emissions are falling,” said a senior analyst participating in the study. “This discrepancy is growing and poses a serious problem. Consequently, PHEVs emit nearly as much as gasoline cars.”

Key Factors Driving the Emissions Gap

Analysts attributed most of the gap to inflated estimates of the “utility factor” – the ratio of kilometers driven in electric mode compared to total distance. They determined that only a quarter of driving was done in electric mode, whereas official assumptions assumed over four-fifths.

Additionally, when operating in electric mode, emission amounts were significantly higher than lab projections. That occurred because EV motors were not strong enough to function independently, resulting to combustion motors using gasoline for nearly a third of the distance completed in electric mode.

Regulatory and Economic Consequences

Based on calculations, the underestimation of PHEV emissions enabled several major automaker groups to avoid over €5bn in fines between 2021 and 2023, by falsely easing adherence with EU fleet-average CO₂ targets.

Furthermore, drivers of PHEVs would spend about €500 more annually in operating costs than would be estimated under lab conditions.

“The strong statements that automakers often promote about their PHEV cars are obviously way off the mark,” commented a transport analyst. “Buyers are being duped into believing that by buying a PHEV, they are helping the planet and saving costs. Actually, PHEVs are only slightly improved than regular gas and diesel cars in terms of fuel consumption, CO₂ emissions, and operating expenses.”

Policy Debate and Industry Lobbying

Plug-in hybrid vehicles have recently been brought back into political debates as carmakers have pressed the European Union to relax CO₂ standards. A planned ban on new combustion engine cars in 2035 has faced heavy pressure from the automotive sector and resistance from EU countries with significant car industries.

Several senior officials have proposed PHEVs as a possible “flexibility” solution to include in the regulation.

One external energy economics expert, who was not involved with the study, described the report a “highly valuable addition” after a long period in which segments of the car industry argued there was too little information to properly assess actual emissions.

“The results show, without question, that the difference in lab and real-world PHEV energy use and CO₂ emissions is significantly greater than for petrol or conventional vehicles,” they said. “Any policy changes concerning PHEVs should be implemented with utmost care and in the light of that evidence.”