Plug in Hybrid electric Vehicles Emit Nearly as Heavily as Petrol Vehicles, Study Finds

Plug-in hybrid cars release almost five times greater planet-heating emissions than lab-reported data indicate, according to a recent analysis.

Widening Discrepancy Between Official and Real-World CO2 Output

Statistics shows that PHEVs emit just 19% lower CO₂ than conventional gas and diesel cars, according to analysis carried out by a non-profit organization. That contrasts sharply with lab estimates, which assumed a three-quarters decrease in pollution.

Analysts examined information from onboard fuel consumption meters of 800,000 cars sold in Europe between 2021 and 2023. They discovered that actual CO₂ output from PHEVs in 2023 were nearly five times greater than official figures, increased from 3.5 times in 2021.

“Actual CO2 output are increasing, while official emissions are falling,” stated a senior researcher participating in the report. “That gap is growing and creates a significant issue. As a result, PHEVs pollute nearly as heavily as petrol vehicles.”

Primary Factors Behind the Emissions Gap

Researchers attributed most of the difference to overestimates of the “utility factor” – the ratio of kilometers driven in battery mode compared to overall distance. They determined that just a quarter of travel was done in EV mode, while lab assumptions suggested 84%.

Additionally, when running in electric mode, pollution levels were well above official projections. This happened because EV motors were insufficiently powerful sufficient to operate alone, resulting to engines burning fossil fuels for almost a third of the travel covered in electric mode.

Regulatory and Economic Consequences

According to calculations, the underestimation of PHEV CO2 output allowed several major carmaker groups to avoid more than €5bn in fines from 2021 and 2023, by artificially easing adherence with European Union fleet-average CO₂ targets.

Additionally, drivers of PHEVs could spend about €500 more annually in running costs than is assumed under lab tests.

“The strong claims that manufacturers often promote about their plug-in hybrid vehicles are clearly far from the truth,” commented a transport analyst. “Consumers are being misled into thinking that by purchasing a PHEV, they are benefiting the environment and saving money. Actually, PHEVs are only slightly better than standard gas and diesel cars in terms of energy use, CO₂ emissions, and operating expenses.”

Political Debate and Industry Lobbying

Plug-in hybrid vehicles have lately been brought again into policy discussions as carmakers have pressed the European Union to weaken CO₂ targets. A proposed prohibition on new combustion engine vehicles in 2035 has faced heavy pressure from the automotive sector and opposition from EU countries with large car manufacturing.

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

An independent energy policy specialist, who was unaffiliated with the study, called the report a “very useful addition” after years in which segments of the automotive industry argued there was too little information to accurately evaluate real-world CO2 output.

“These findings demonstrate, beyond any doubt, that the gap in official and actual PHEV fuel consumption and CO₂ output is significantly larger than for gasoline or conventional cars,” they said. “Any regulatory changes regarding PHEVs should be implemented with utmost caution and in the light of this evidence.”