🔗 Share this article

Plug-in hybrid electric vehicles emit nearly five times more planet-heating pollution than lab-reported data show, according to a new report.

Widening Discrepancy Between Official and Actual Emissions

Statistics reveals that PHEVs release just one-fifth less CO₂ than conventional petrol and diesel vehicles, based on analysis carried out by a non-profit organization. This differs significantly with laboratory estimates, which suggested a 75% reduction in emissions.

Researchers studied data from onboard fuel consumption meters of eight hundred thousand cars registered in the EU between 2021 and 2023. They found that actual CO₂ emissions from PHEVs in 2023 were nearly five times higher than lab figures, increased from three and a half times in 2021.

“Actual CO2 output are increasing, while lab-reported figures are falling,” stated a senior researcher involved in the study. “This gap is widening and poses a serious problem. As a result, PHEVs emit nearly as much as petrol vehicles.”

Key Factors Driving the Emissions Gap

Researchers attributed most of the difference to inflated estimates of the “electric driving share” – the ratio of kilometers driven in battery power compared to overall distance. They found that only a quarter of driving was done in electric mode, whereas official assumptions suggested over four-fifths.

Even, when running in electric mode, pollution amounts were significantly higher than lab projections. That happened because electric motors were insufficiently powerful sufficient to operate alone, resulting to combustion motors burning fossil fuels for almost a third of the travel completed in EV mode.

Policy and Economic Implications

Based on calculations, the lowballing of PHEV emissions enabled four major carmaker groups to avoid over €5bn in fines from 2021 and 2023, by falsely simplifying adherence with EU average fleet CO₂ standards.

Furthermore, drivers of PHEVs could pay about €500 extra annually in running expenses than is estimated under lab tests.

“The strong claims that manufacturers often promote about their plug-in hybrid vehicles are obviously far from the truth,” stated a automotive analyst. “Buyers are being duped into believing that by purchasing a PHEV, they are benefiting the environment and saving costs. In reality, PHEVs are little improved than standard petrol and diesel vehicles in terms of energy use, CO₂ emissions, and operating costs.”

Political Discussion and Automotive Pressure

Hybrid cars have lately been drawn again into policy discussions as carmakers have pressed the European Union to relax CO₂ standards. A proposed prohibition on sales of new internal combustion vehicles in 2035 has faced intense lobbying from the automotive sector and opposition from EU countries with significant car manufacturing.

Some high-level officials have suggested plug-in hybrids as a potential “flexibility” solution to introduce in the regulation.

One independent energy economics expert, who was not involved with the study, described the report a “very useful addition” after years in which parts of the car industry argued there was too little data to properly assess real-world emissions.

“These findings demonstrate, without question, that the difference in lab and actual PHEV energy use and CO₂ emissions is significantly larger than for gasoline or diesel cars,” the expert said. “Any regulatory changes regarding PHEVs should be implemented with utmost caution and in the light of this data.”