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

PHEVs produce almost 5x greater global warming emissions than lab-reported data indicate, as per a new report.

Widening Gap Between Lab and Real-World Emissions

Data shows that PHEVs release only 19% less CO₂ than conventional petrol and diesel vehicles, according to research carried out by a advocacy organization. This contrasts sharply with laboratory estimates, which assumed a 75% reduction in emissions.

Researchers examined data from in-vehicle fuel consumption monitors of 800,000 vehicles sold in Europe between 2021 and 2023. They found that actual CO₂ emissions from PHEVs in 2023 were nearly five times greater than official estimates, increased from 3.5 times in 2021.

“Real-world emissions are increasing, while lab-reported figures are falling,” stated a senior analyst participating in the study. “That discrepancy is widening and creates a significant problem. As a result, PHEVs emit almost as much as petrol vehicles.”

Key Factors Behind the Discrepancy

Analysts attributed the majority of the gap to overestimates of the “utility factor” – the percentage of miles driven in electric mode compared to total distance. They determined that only 27% of travel was completed in EV mode, whereas official estimates assumed over four-fifths.

Even, when running in EV mode, emission levels were significantly higher than official projections. That occurred because EV motors were not strong enough to operate alone, leading to engines using gasoline for almost one-third of the travel covered in EV mode.

Policy and Financial Implications

Based on calculations, the lowballing of PHEV emissions enabled four large carmaker companies to escape more than €5bn in penalties between 2021 and 2023, by artificially easing compliance with European Union fleet-average CO₂ targets.

Additionally, owners of PHEVs would pay approximately €500 extra annually in operating expenses than is estimated under lab conditions.

“The strong statements that manufacturers like to make about their plug-in hybrid cars are obviously way off the mark,” stated a automotive analyst. “Consumers are being duped into believing that by buying a PHEV, they are benefiting the planet and cutting costs. Actually, PHEVs are little improved than standard gas and diesel cars in terms of fuel use, CO₂ emissions, and running costs.”

Political Discussion and Industry Lobbying

Plug-in hybrid vehicles have lately been brought back into policy discussions as carmakers have pressed the EU to relax CO₂ targets. A planned prohibition on new combustion engine cars in 2035 has faced intense pressure from the automotive industry and resistance from member states with significant automotive industries.

Some senior officials have proposed PHEVs as a possible “compromise” solution to include in the legislation.

One external energy policy expert, who was unaffiliated with the study, called the analysis a “highly valuable contribution” after a long period in which parts of the car industry argued there was insufficient information to accurately evaluate real-world CO2 output.

“These findings show, without question, that the difference between lab and actual PHEV fuel consumption and CO₂ emissions is significantly greater than for gasoline or conventional vehicles,” the expert stated. “Any regulatory adjustments concerning PHEVs should be made with utmost care and considering this evidence.”