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PHEVs release almost five times greater global warming pollution than lab-reported data indicate, as per a recent analysis.

Widening Discrepancy In Lab and Real-World Emissions

Statistics reveals that PHEVs release only one-fifth less CO₂ than conventional petrol and diesel cars, according to research carried out by a advocacy group. That differs sharply with lab estimates, which suggested a three-quarters reduction in emissions.

Researchers examined information from onboard fuel consumption monitors of eight hundred thousand cars sold in the EU from 2021 and 2023. They discovered that real-world CO₂ emissions from PHEVs in 2023 were nearly five times higher than official figures, up from three and a half times in 2021.

“Real-world emissions are rising, while lab-reported emissions are decreasing,” stated a senior researcher participating in the report. “This gap is growing and creates a serious issue. Consequently, PHEVs pollute nearly as heavily as petrol cars.”

Primary Reasons Driving the Discrepancy

Researchers attributed the majority of the difference to overestimates of the “electric driving share” – the percentage of kilometers driven in battery power compared to overall mileage. The team found that just 27% of travel was completed in electric mode, whereas official assumptions suggested over four-fifths.

Additionally, when operating in electric mode, pollution amounts were well above official projections. This occurred because electric motors were not strong sufficient to operate alone, leading to engines burning fossil fuels for almost a third of the distance completed in electric mode.

Regulatory and Economic Consequences

According to calculations, the underestimation of PHEV CO2 output enabled four large carmaker groups to avoid more than €5bn in penalties between 2021 and 2023, by artificially easing compliance with European Union fleet-average CO₂ standards.

Additionally, owners of PHEVs could spend about €500 extra annually in operating expenses than would be estimated under lab conditions.

“The strong statements that automakers like to make about their PHEV cars are obviously way off the truth,” stated a transport analyst. “Consumers are being misled into thinking that by buying a PHEV, they are helping the environment and saving money. Actually, PHEVs are little better than regular petrol and diesel cars in terms of fuel use, CO₂ emissions, and running costs.”

Political Discussion and Automotive Lobbying

Hybrid cars have recently been brought back into political discussions as carmakers have lobbied the European Union to relax CO₂ standards. A planned ban on new combustion engine cars in 2035 has faced heavy pressure from the automotive industry and resistance from member states with significant car manufacturing.

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

One external energy economics specialist, who was not involved with the study, described the report a “very useful addition” after a long period in which parts of the car sector argued there was too little information to properly evaluate real-world CO2 output.

“The results demonstrate, without question, that the gap between lab and actual PHEV fuel consumption and CO₂ emissions is much, much greater than for petrol or diesel vehicles,” they stated. “All regulatory adjustments concerning PHEVs should be made with extreme caution and in the light of that evidence.”