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PHEVs release almost 5x greater planet-heating emissions than official figures indicate, as per a new analysis.

Widening Discrepancy Between Official and Real-World Emissions

Statistics reveals that PHEVs emit just one-fifth less CO₂ than conventional petrol and diesel vehicles, based on research conducted by a non-profit group. That differs significantly with lab estimates, which assumed a three-quarters decrease in pollution.

Analysts studied data from onboard fuel consumption meters of eight hundred thousand vehicles registered in Europe from 2021 and 2023. They discovered that real-world CO₂ emissions from PHEVs in 2023 were nearly five times greater than lab estimates, increased from 3.5 times in 2021.

“Real-world CO2 output are increasing, while lab-reported emissions are decreasing,” stated a lead researcher involved in the report. “This gap is widening and creates a significant issue. As a result, PHEVs pollute nearly as heavily as gasoline cars.”

Key Reasons Behind the Emissions Gap

Researchers attributed the majority of the difference to inflated estimates of the “electric driving share” – the ratio of kilometers driven in battery mode compared to total distance. The team found that just a quarter of travel was completed in EV mode, whereas official assumptions suggested over four-fifths.

Additionally, when operating in EV mode, pollution amounts were well above lab projections. This happened because EV motors were insufficiently powerful sufficient to function alone, leading to engines burning fossil fuels for almost a third of the travel completed in EV mode.

Regulatory and Economic Consequences

Based on estimates, the lowballing of PHEV emissions allowed four large carmaker groups to escape more than €5bn in penalties between 2021 and 2023, by falsely simplifying compliance with European Union average fleet CO₂ standards.

Furthermore, owners of PHEVs could spend approximately €500 extra per year in operating costs than is estimated under laboratory conditions.

“The bold statements that automakers like to make about their plug-in hybrid cars are clearly far from the truth,” commented a transport analyst. “Buyers are being misled into believing that by purchasing a PHEV, they are benefiting the planet and saving money. Actually, PHEVs are little improved than regular gas and diesel cars in terms of fuel consumption, CO₂ emissions, and running costs.”

Political Discussion and Automotive Lobbying

Hybrid vehicles have recently been brought back into political debates as automakers have pressed the EU to weaken CO₂ standards. A planned prohibition on sales of new combustion engine cars in 2035 has faced heavy lobbying from the automotive sector and resistance from member states with large automotive industries.

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

An external energy policy expert, who was unaffiliated with the study, described the report a “very useful contribution” after years in which parts of the automotive sector claimed there was insufficient data to accurately assess actual CO2 output.

“These findings demonstrate, beyond any doubt, that the difference between official and actual PHEV energy use and CO₂ emissions is much, much greater than for petrol or conventional cars,” they stated. “All policy adjustments concerning PHEVs should be implemented with utmost caution and considering that data.”