Plug in Hybrid electric Vehicles Pollute Nearly as Heavily as Gasoline Cars, Report Finds

PHEVs emit nearly five times greater global warming pollution than official figures show, according to a new report.

Growing Gap Between Lab and Real-World CO2 Output

Statistics shows that PHEVs release only one-fifth less CO₂ than conventional gas and diesel cars, according to analysis conducted by a non-profit organization. This differs significantly with laboratory tests, which assumed a 75% reduction in emissions.

Researchers studied data from onboard energy use meters of eight hundred thousand vehicles sold in Europe from 2021 and 2023. The team found that actual CO₂ emissions from PHEVs in 2023 were nearly five times greater than official estimates, up from 3.5 times in 2021.

“Real-world emissions are increasing, while lab-reported figures are decreasing,” said a senior analyst participating in the study. “This gap is widening and creates a serious issue. As a result, PHEVs pollute nearly as heavily as gasoline vehicles.”

Primary Reasons Behind the Emissions Gap

Researchers attributed most of the difference to inflated estimates of the “electric driving share” – the percentage of miles driven in electric power relative to overall mileage. The team found that only a quarter of driving was completed in EV mode, whereas lab assumptions assumed 84%.

Even, when operating in EV mode, emission amounts were significantly higher than official projections. This occurred because electric motors were not strong sufficient to function independently, resulting to engines burning fossil fuels for almost a third of the travel covered in electric mode.

Regulatory and Financial Consequences

According to calculations, the underestimation of PHEV CO2 output enabled four large automaker companies to avoid over €5bn in fines from 2021 and 2023, by falsely simplifying adherence with EU average fleet CO₂ targets.

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

“The bold claims that automakers often promote about their PHEV cars are clearly far from the mark,” stated a automotive expert. “Consumers are being duped into believing that by purchasing a PHEV, they are benefiting the environment and saving costs. Actually, PHEVs are only slightly improved than regular petrol and diesel cars in terms of energy use, CO₂ emissions, and operating costs.”

Policy Discussion and Industry Lobbying

Plug-in hybrid cars have recently been drawn again into policy discussions as automakers have pressed the European Union to weaken CO₂ standards. A proposed prohibition on sales of new combustion engine cars in 2035 has faced heavy pressure from the automotive sector and resistance from EU countries with large automotive industries.

Several high-level officials have proposed plug-in hybrids as a potential “flexibility” solution to include in the regulation.

An independent energy economics specialist, who was unaffiliated with the research, called the report a “very useful contribution” after years in which segments of the car sector argued there was too little information to properly assess actual CO2 output.

“The results demonstrate, beyond any doubt, that the gap in lab and actual PHEV energy use and CO₂ emissions is much, much greater than for gasoline or conventional vehicles,” they stated. “All policy changes regarding PHEVs should be implemented with utmost care and considering that data.”