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PHEVs emit almost five times more global warming emissions than lab-reported data show, according to a recent analysis.

Growing Gap In Lab and Actual CO2 Output

Data reveals that PHEVs emit just one-fifth lower CO₂ than traditional petrol and diesel vehicles, according to analysis carried out by a advocacy group. This contrasts significantly with laboratory tests, which suggested a three-quarters reduction in pollution.

Researchers studied data from in-vehicle fuel consumption meters of eight hundred thousand cars sold in the EU between 2021 and 2023. They found that real-world CO₂ emissions from PHEVs in 2023 were nearly five times greater than official figures, up from three and a half times in 2021.

“Real-world emissions are increasing, while lab-reported figures are falling,” stated a senior researcher participating in the report. “This discrepancy is widening and creates a significant issue. Consequently, PHEVs pollute nearly as much as petrol cars.”

Primary Reasons Driving the Emissions Gap

Analysts linked most of the difference to overestimates of the “utility factor” – the ratio of miles driven in battery mode relative to overall mileage. The team determined that only 27% of travel was done in electric mode, while lab assumptions assumed over four-fifths.

Even, when operating in EV mode, emission amounts were well above lab estimates. This occurred because electric motors were not strong sufficient to function independently, resulting to engines using fossil fuels for nearly a third of the travel completed in electric mode.

Regulatory and Financial Consequences

Based on estimates, the underestimation of PHEV CO2 output allowed four large carmaker groups to escape more than €5bn in penalties between 2021 and 2023, by falsely easing adherence with EU fleet-average CO₂ standards.

Furthermore, owners of PHEVs could spend approximately €500 extra per year in operating expenses than is estimated under lab conditions.

“The strong claims that automakers like to make about their PHEV vehicles are obviously far from the mark,” commented a automotive analyst. “Buyers are being duped into thinking that by buying a PHEV, they are helping the environment and saving money. Actually, PHEVs are only slightly better than standard petrol and diesel vehicles in terms of fuel use, CO₂ emissions, and running expenses.”

Policy Discussion and Industry Pressure

Plug-in hybrid vehicles have lately been drawn back into policy discussions as automakers have pressed the EU to weaken CO₂ standards. A proposed prohibition on sales of new internal combustion vehicles in 2035 has faced heavy lobbying from the automotive sector and opposition from EU countries with significant automotive manufacturing.

Several senior officials have suggested plug-in hybrids as a potential “flexibility” solution to introduce in the regulation.

An independent energy policy specialist, who was not involved with the research, called the report a “very useful addition” after a long period in which segments of the car industry claimed there was insufficient data to accurately evaluate actual emissions.

“These findings demonstrate, beyond any doubt, that the gap in lab and actual PHEV energy use and CO₂ emissions is much, much larger than for gasoline or conventional vehicles,” they said. “Any regulatory adjustments concerning PHEVs should be implemented with utmost care and considering that data.”