Plug in Hybrid Vehicles Pollute Almost as Heavily as Petrol Cars, Study Finds

Plug-in hybrid cars release almost 5x more planet-heating emissions than lab-reported data indicate, as per a recent analysis.

Growing Gap Between Lab and Real-World Emissions

Statistics shows that PHEVs emit only one-fifth lower CO₂ than conventional petrol and diesel cars, according to research conducted by a non-profit organization. That differs significantly with laboratory estimates, which assumed a 75% reduction in emissions.

Researchers studied information from onboard energy use meters of eight hundred thousand vehicles sold in Europe between 2021 and 2023. They found that real-world CO₂ emissions from PHEVs in 2023 were nearly five times greater than official estimates, up from three and a half times in 2021.

“Actual CO2 output are rising, while lab-reported emissions are falling,” stated a lead researcher involved in the report. “That gap is growing and creates a significant problem. Consequently, PHEVs pollute almost as heavily as petrol cars.”

Primary Reasons Behind the Discrepancy

Analysts linked most of the gap to overestimates of the “electric driving share” – the ratio of miles driven in battery power compared to total mileage. The team determined that just a quarter of driving was done in EV mode, while official assumptions suggested over four-fifths.

Even, when running in electric mode, emission amounts were significantly higher than lab estimates. That happened because electric motors were insufficiently powerful sufficient to function alone, leading to combustion motors using gasoline for almost a third of the distance covered in electric mode.

Policy and Financial Consequences

Based on calculations, the lowballing of PHEV emissions allowed four major carmaker companies to escape more than €5bn in penalties between 2021 and 2023, by falsely simplifying compliance with EU average fleet CO₂ standards.

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

“The strong statements that automakers often promote about their PHEV vehicles are clearly way off the truth,” commented a transport analyst. “Buyers are being duped into believing that by buying a PHEV, they are benefiting the environment and cutting costs. In reality, PHEVs are little better than standard gas and diesel vehicles in terms of energy use, CO₂ production, and operating costs.”

Policy Debate and Automotive Pressure

Hybrid cars have recently been drawn again into political debates as carmakers have lobbied the European Union to weaken CO₂ standards. A proposed prohibition on new internal combustion cars in 2035 has faced intense lobbying from the automotive industry and resistance from member states with large car industries.

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

One independent energy economics expert, who was unaffiliated with the study, called the report a “highly valuable addition” after a long period in which parts of the car industry argued there was insufficient information to accurately evaluate actual CO2 output.

“The results demonstrate, without question, that the gap in lab and actual PHEV fuel consumption and CO₂ emissions is much, much larger than for gasoline or diesel vehicles,” they stated. “Any policy adjustments regarding PHEVs should be made with utmost caution and in the light of this evidence.”