Plug-in Hybrid electric Vehicles Pollute Nearly as Much as Petrol Cars, Study Finds

Plug-in hybrid electric vehicles produce almost five times greater planet-heating emissions than official figures show, as per a recent analysis.

Growing Discrepancy Between Official and Actual Emissions

Statistics reveals that PHEVs emit just one-fifth lower CO₂ than conventional petrol and diesel cars, according to analysis carried out by a advocacy group. That differs significantly with laboratory tests, which assumed a three-quarters reduction in pollution.

Analysts studied data from in-vehicle energy use monitors of eight hundred thousand cars sold in Europe from 2021 and 2023. They found that real-world CO₂ output from PHEVs in 2023 were 4.9 times higher than official estimates, increased from three and a half times in 2021.

“Real-world CO2 output are rising, while lab-reported emissions are falling,” said a senior researcher involved in the study. “That gap is growing and poses a serious issue. Consequently, PHEVs emit almost as much as petrol cars.”

Key Reasons Driving the Discrepancy

Analysts linked most of the difference to overestimates of the “electric driving share” – the ratio of kilometers driven in battery mode compared to overall mileage. The team determined that just 27% of travel was completed in EV mode, whereas official assumptions suggested 84%.

Even, when operating in electric mode, pollution levels were significantly higher than official projections. This happened because EV motors were insufficiently powerful enough to function alone, leading to combustion motors using gasoline for nearly a third of the travel completed in EV mode.

Regulatory and Financial Implications

According to estimates, the lowballing of PHEV emissions enabled four major automaker groups to avoid more than €5bn in penalties from 2021 and 2023, by falsely easing compliance with European Union fleet-average CO₂ standards.

Additionally, drivers of PHEVs could pay approximately €500 extra per year in running costs than is estimated under laboratory conditions.

“The bold statements that manufacturers like to make about their plug-in hybrid cars are obviously far from the mark,” stated a automotive expert. “Consumers are being misled into thinking that by purchasing a PHEV, they are benefiting the planet and saving costs. Actually, PHEVs are little better than standard gas and diesel vehicles in terms of energy use, CO₂ emissions, and running costs.”

Political Debate and Automotive Pressure

Hybrid cars have lately been drawn back into political discussions as automakers have pressed the European Union to relax CO₂ standards. A planned prohibition on sales of new internal combustion vehicles in 2035 has faced heavy pressure from the car industry and resistance from member states with large automotive manufacturing.

Several senior politicians have suggested PHEVs as a possible “flexibility” solution to introduce in the legislation.

One independent energy policy expert, who was unaffiliated with the study, described the report a “highly valuable addition” after years in which segments of the automotive industry argued there was insufficient information to properly evaluate real-world CO2 output.

“These findings show, without question, that the gap in lab and real-world PHEV fuel consumption and CO₂ emissions is much, much greater than for gasoline or conventional cars,” they said. “Any policy changes regarding PHEVs should be implemented with utmost care and in the light of that data.”