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

Plug-in hybrid electric vehicles emit nearly five times greater global warming pollution than lab-reported figures show, as per a new report.

Widening Gap Between Lab and Actual Emissions

Data reveals that PHEVs release just 19% less CO₂ than traditional petrol and diesel cars, based on research conducted by a non-profit organization. This differs sharply with laboratory estimates, which suggested a three-quarters reduction in emissions.

Analysts examined information from onboard fuel consumption monitors of eight hundred thousand vehicles registered in Europe from 2021 and 2023. The team discovered that actual CO₂ output from PHEVs in 2023 were nearly five times greater than official figures, increased from three and a half times in 2021.

“Real-world CO2 output are increasing, while official figures are decreasing,” said a senior researcher participating in the report. “That discrepancy is growing and creates a serious issue. Consequently, PHEVs pollute nearly as heavily as gasoline cars.”

Key Factors Driving the Discrepancy

Researchers linked most of the difference to overestimates of the “electric driving share” – the ratio of kilometers travelled in electric power compared to overall mileage. They determined that just 27% of travel was completed in EV mode, whereas official assumptions suggested over four-fifths.

Even, when operating in electric mode, emission levels were well above official estimates. That happened because electric motors were insufficiently powerful enough to operate alone, resulting to combustion motors using gasoline for almost a third of the travel covered in EV mode.

Regulatory and Financial Implications

Based on calculations, the underestimation of PHEV emissions enabled four large automaker companies to escape more than €5bn in penalties from 2021 and 2023, by artificially simplifying compliance with European Union fleet-average CO₂ standards.

Furthermore, drivers of PHEVs could pay about €500 extra per year in operating expenses than would be assumed under laboratory conditions.

“The bold statements that manufacturers like to make about their plug-in hybrid vehicles are obviously far from the truth,” commented a automotive expert. “Buyers are being misled into believing that by buying a PHEV, they are benefiting the planet and cutting money. Actually, PHEVs are only slightly improved than standard petrol and diesel cars in terms of fuel use, CO₂ production, and running expenses.”

Policy Discussion and Automotive Pressure

Hybrid vehicles have recently been drawn again into policy discussions as automakers have pressed the EU to weaken CO₂ targets. A proposed ban on sales of new internal combustion cars in 2035 has faced heavy pressure from the car sector and resistance from member states with significant car industries.

Some senior officials have suggested PHEVs as a potential “flexibility” solution to introduce in the legislation.

One external energy policy expert, who was unaffiliated with the study, described the analysis a “highly valuable contribution” after years in which parts of the automotive sector argued there was insufficient data to properly assess actual CO2 output.

“The results show, without question, that the difference in lab and real-world PHEV energy use and CO₂ emissions is significantly larger than for gasoline or conventional cars,” they stated. “Any regulatory adjustments concerning PHEVs should be implemented with extreme care and considering this data.”