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PHEVs emit nearly 5x more planet-heating pollution than official data show, according to a recent report.

Growing Discrepancy Between Lab and Real-World CO2 Output

Statistics reveals that PHEVs emit only one-fifth lower CO₂ than traditional gas and diesel vehicles, based on analysis carried out by a non-profit organization. That contrasts significantly with lab tests, which assumed a 75% reduction in pollution.

Researchers examined information from in-vehicle fuel consumption monitors of eight hundred thousand cars registered in Europe from 2021 and 2023. They found that actual CO₂ output from PHEVs in 2023 were nearly five times greater than lab figures, up from 3.5 times in 2021.

“Actual CO2 output are rising, while official emissions are falling,” said a senior analyst involved in the report. “That discrepancy is widening and poses a serious issue. Consequently, PHEVs emit almost as heavily as gasoline cars.”

Primary Reasons Behind the Emissions Gap

Researchers linked most of the difference to overestimates of the “electric driving share” – the percentage of kilometers driven in electric power relative to total mileage. The team found that just a quarter of travel was completed in EV mode, while official assumptions assumed 84%.

Additionally, when running in electric mode, emission amounts were well above official projections. This happened because electric motors were insufficiently powerful sufficient to function alone, leading to engines using fossil fuels for nearly a third of the distance covered in EV mode.

Regulatory and Financial Consequences

Based on calculations, the lowballing of PHEV CO2 output enabled four large carmaker companies to escape over €5bn in penalties between 2021 and 2023, by falsely easing adherence with EU average fleet CO₂ standards.

Furthermore, owners of PHEVs could pay approximately €500 extra annually in running costs than is estimated under laboratory conditions.

“The bold claims that manufacturers like to make about their PHEV cars are clearly far from the truth,” stated a automotive expert. “Consumers are being duped into believing that by buying a PHEV, they are helping the environment and cutting money. In reality, PHEVs are little improved than standard gas and diesel vehicles in terms of fuel use, CO₂ emissions, and running expenses.”

Policy Discussion and Automotive Lobbying

Plug-in hybrid vehicles have lately been brought again into policy debates as carmakers have lobbied the European Union to weaken CO₂ targets. A planned ban on new internal combustion cars in 2035 has faced heavy pressure from the automotive sector and resistance from member states with significant automotive manufacturing.

Several senior politicians have suggested PHEVs as a possible “flexibility” option to include in the legislation.

One external energy policy specialist, who was unaffiliated with the research, described the report a “very useful contribution” after years in which parts of the automotive industry argued there was too little information to accurately evaluate actual emissions.

“These findings show, beyond any doubt, that the gap between official and real-world PHEV energy use and CO₂ emissions is significantly larger than for petrol or diesel cars,” they said. “Any regulatory adjustments concerning PHEVs should be implemented with utmost care and in the light of this evidence.”