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Plug-in hybrid electric vehicles release almost five times more planet-heating pollution than official figures show, as per a new analysis.

Widening Gap In Official and Actual CO2 Output

Statistics shows that PHEVs emit just one-fifth lower CO₂ than conventional gas and diesel cars, according to analysis carried out by a non-profit group. That contrasts significantly with laboratory tests, which suggested a three-quarters decrease in pollution.

Analysts studied information from onboard fuel consumption meters of 800,000 cars sold in Europe from 2021 and 2023. The team found that real-world CO₂ output from PHEVs in 2023 were nearly five times higher than lab estimates, increased from three and a half times in 2021.

“Real-world CO2 output are increasing, while official emissions are decreasing,” said a lead analyst participating in the report. “This discrepancy is growing and creates a significant problem. As a result, PHEVs pollute nearly as much as petrol cars.”

Primary Reasons Behind the Emissions Gap

Analysts linked most of the difference to overestimates of the “utility factor” – the percentage of miles driven in battery mode relative to total distance. The team found that just 27% of travel was completed in EV mode, whereas official estimates suggested 84%.

Even, when operating in EV mode, pollution levels were significantly higher than lab projections. That occurred because electric motors were insufficiently powerful sufficient to function alone, leading to combustion motors using gasoline for nearly a third of the distance completed in EV mode.

Regulatory and Economic Consequences

According to estimates, the underestimation of PHEV emissions allowed several large automaker groups to escape more than €5bn in penalties from 2021 and 2023, by artificially easing adherence with European Union fleet-average CO₂ standards.

Furthermore, owners of PHEVs would pay about €500 extra annually in running costs than would be estimated under lab tests.

“The bold statements that manufacturers like to make about their PHEV cars are clearly way off the mark,” commented a automotive expert. “Buyers are being duped into believing that by buying a PHEV, they are helping the environment and cutting money. In reality, PHEVs are only slightly improved than standard petrol and diesel vehicles in terms of energy consumption, CO₂ production, and operating costs.”

Political Debate and Automotive Lobbying

Hybrid vehicles have lately been brought back into political discussions as carmakers have lobbied the European Union to weaken CO₂ targets. A planned ban on new internal combustion cars in 2035 has faced heavy lobbying from the car sector and resistance from EU countries with significant automotive industries.

Several senior officials have proposed PHEVs as a potential “flexibility” solution to include in the regulation.

An external energy economics expert, who was unaffiliated with the research, described the report a “highly valuable contribution” after a long period in which parts of the automotive sector argued there was insufficient data to accurately evaluate actual emissions.

“The results show, beyond any doubt, that the difference between official and actual PHEV energy use and CO₂ output is much, much larger than for gasoline or conventional cars,” the expert stated. “Any policy changes concerning PHEVs should be implemented with extreme caution and in the light of that data.”