Plug in Hybrid electric Cars Emit Almost as Much as Gasoline Cars, Study Reveals

PHEVs emit almost five times greater global warming pollution than official data indicate, as per a recent analysis.

Widening Gap Between Official and Actual Emissions

Data reveals that PHEVs release only one-fifth lower CO₂ than traditional petrol and diesel cars, according to analysis conducted by a non-profit organization. That contrasts significantly with lab tests, which assumed a 75% reduction in pollution.

Analysts studied information from in-vehicle energy use monitors of 800,000 cars registered in Europe from 2021 and 2023. The team found that actual CO₂ emissions from PHEVs in 2023 were 4.9 times higher than official figures, up from 3.5 times in 2021.

“Actual CO2 output are rising, while lab-reported emissions are decreasing,” said a lead researcher involved in the study. “This discrepancy is widening and poses a significant problem. As a result, PHEVs emit nearly as heavily as petrol vehicles.”

Key Factors Driving the Discrepancy

Researchers linked the majority of the difference to overestimates of the “utility factor” – the percentage of kilometers driven in battery mode compared to overall distance. They found that just 27% of driving was completed in EV mode, while lab estimates assumed 84%.

Additionally, when operating in electric mode, emission amounts were significantly higher than official projections. This happened because electric motors were insufficiently powerful enough to function alone, leading to engines using gasoline for nearly a third of the travel completed in electric mode.

Regulatory and Financial Consequences

Based on calculations, the lowballing of PHEV emissions enabled four major automaker groups to avoid more than €5bn in fines between 2021 and 2023, by artificially simplifying adherence with EU fleet-average CO₂ targets.

Additionally, drivers of PHEVs could spend approximately €500 extra annually in running expenses than is assumed under laboratory conditions.

“The strong statements that automakers like to make about their PHEV vehicles are clearly far from the truth,” stated a transport analyst. “Consumers are being misled into believing that by buying a PHEV, they are helping the environment and cutting money. In reality, PHEVs are little better than standard gas and diesel cars in terms of energy use, CO₂ emissions, and running expenses.”

Political Discussion and Industry Lobbying

Plug-in hybrid vehicles have lately been brought again into policy debates as automakers have lobbied the EU to relax CO₂ standards. A proposed ban on sales of new combustion engine cars in 2035 has faced heavy lobbying from the automotive sector and opposition from member states with large car manufacturing.

Several senior officials have proposed plug-in hybrids as a potential “compromise” solution to include in the legislation.

One external energy policy specialist, who was unaffiliated with the research, called the analysis a “highly valuable addition” after a long period in which segments of the car industry claimed there was too little data to accurately evaluate actual CO2 output.

“These findings demonstrate, without question, that the gap in official and actual PHEV fuel consumption and CO₂ output is much, much greater than for gasoline or diesel cars,” the expert said. “All regulatory adjustments regarding PHEVs should be made with utmost caution and considering that data.”