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Plug-in hybrid electric vehicles release nearly 5x greater planet-heating pollution than lab-reported figures show, as per a new report.

Growing Gap In Lab and Actual CO2 Output

Statistics shows that PHEVs release just 19% lower CO₂ than conventional gas and diesel vehicles, based on analysis carried out by a advocacy organization. This contrasts sharply with lab estimates, which assumed a three-quarters reduction in pollution.

Researchers studied data from onboard fuel consumption monitors of eight hundred thousand cars registered in Europe between 2021 and 2023. The team discovered that real-world CO₂ output from PHEVs in 2023 were 4.9 times higher than lab estimates, up from 3.5 times in 2021.

“Actual CO2 output are rising, while lab-reported emissions are falling,” said a lead analyst involved in the report. “This discrepancy is growing and creates a significant issue. As a result, PHEVs pollute nearly as much as petrol vehicles.”

Primary Reasons Behind the Emissions Gap

Analysts linked most of the gap to overestimates of the “utility factor” – the ratio of kilometers travelled in electric mode compared to overall mileage. The team found that just a quarter of driving was completed in electric mode, while official estimates assumed 84%.

Even, when running in EV mode, emission amounts were well above lab projections. This occurred because electric motors were insufficiently powerful enough to function independently, leading to combustion motors using gasoline for almost a third of the distance completed in EV mode.

Policy and Financial Implications

According to estimates, the lowballing of PHEV CO2 output enabled several large automaker groups to avoid more than €5bn in fines from 2021 and 2023, by artificially easing compliance with EU fleet-average CO₂ standards.

Additionally, drivers of PHEVs would pay approximately €500 extra annually in running costs than would be estimated under lab tests.

“The bold statements that automakers like to make about their plug-in hybrid cars are clearly way off the mark,” stated a automotive expert. “Consumers are being misled into believing that by purchasing a PHEV, they are helping the environment and cutting costs. In reality, PHEVs are only slightly better than regular petrol and diesel vehicles in terms of fuel consumption, CO₂ production, and running expenses.”

Policy Discussion and Industry Pressure

Hybrid vehicles have lately been drawn again into political debates as carmakers have lobbied the EU to relax CO₂ targets. A proposed ban on new combustion engine cars in 2035 has faced intense lobbying from the automotive industry and resistance from EU countries with significant car manufacturing.

Some senior politicians have proposed plug-in hybrids as a potential “flexibility” solution to introduce in the legislation.

One independent energy economics specialist, who was not involved with the research, called the report a “very useful contribution” after a long period in which segments of the automotive sector argued there was insufficient data to accurately assess actual CO2 output.

“These findings demonstrate, beyond any doubt, that the gap in lab and real-world PHEV energy use and CO₂ emissions is much, much greater than for petrol or conventional vehicles,” the expert said. “All regulatory adjustments regarding PHEVs should be implemented with utmost caution and considering this evidence.”