Plug in Hybrid electric Vehicles Emit Almost as Much as Gasoline Cars, Report Reveals

Plug-in hybrid electric vehicles produce almost five times greater planet-heating emissions than lab-reported data indicate, according to a new analysis.

Growing Gap Between Official and Actual Emissions

Statistics reveals that PHEVs emit only one-fifth lower CO₂ than conventional petrol and diesel vehicles, according to analysis conducted by a advocacy organization. That differs sharply with laboratory tests, which assumed a three-quarters decrease in pollution.

Researchers studied information from in-vehicle fuel consumption meters of 800,000 vehicles sold in the EU from 2021 and 2023. They discovered that actual CO₂ output from PHEVs in 2023 were nearly five times greater than lab estimates, increased from 3.5 times in 2021.

“Real-world CO2 output are rising, while official figures are falling,” said a senior analyst involved in the report. “That gap is growing and poses a significant problem. As a result, PHEVs emit nearly as much as petrol vehicles.”

Key Reasons Driving the Emissions Gap

Analysts attributed most of the difference to overestimates of the “electric driving share” – the percentage of miles travelled in battery power compared to overall mileage. The team determined that only a quarter of driving was done in electric mode, while lab estimates assumed 84%.

Additionally, when operating in EV mode, pollution levels were well above official projections. That occurred because EV motors were not strong enough to operate independently, leading to combustion motors burning gasoline for nearly one-third of the distance covered in electric mode.

Policy and Financial Consequences

Based on estimates, the underestimation of PHEV CO2 output enabled several major automaker groups to avoid more than €5bn in fines from 2021 and 2023, by artificially simplifying compliance with European Union fleet-average CO₂ standards.

Furthermore, drivers of PHEVs could pay approximately €500 extra annually in operating costs than would be estimated under lab conditions.

“The strong claims that automakers like to make about their PHEV cars are clearly far from the truth,” commented a transport expert. “Consumers are being duped into believing that by purchasing a PHEV, they are helping the environment and cutting money. Actually, PHEVs are only slightly better than standard petrol and diesel vehicles in terms of fuel use, CO₂ production, and operating expenses.”

Political Debate and Industry Lobbying

Hybrid cars have recently been brought back into policy discussions as carmakers have lobbied the European Union to relax CO₂ standards. A planned ban on sales of new internal combustion cars in 2035 has faced intense pressure from the car sector and resistance from member states with large automotive manufacturing.

Several high-level politicians have proposed PHEVs as a possible “flexibility” option to introduce in the legislation.

An external energy policy expert, who was unaffiliated with the study, described the report a “very useful addition” after a long period in which parts of the car industry argued there was too little data to properly evaluate real-world CO2 output.

“The results demonstrate, without question, that the difference in lab and actual PHEV fuel consumption and CO₂ emissions is significantly greater than for petrol or conventional vehicles,” the expert stated. “Any regulatory changes regarding PHEVs should be made with utmost care and considering this evidence.”