Plug-in Hybrid electric Vehicles Pollute Nearly as Heavily as Petrol Vehicles, Study Reveals

Plug-in hybrid cars release nearly five times more global warming emissions than official data show, as per a recent report.

Widening Discrepancy In Official and Real-World Emissions

Data reveals that PHEVs release just one-fifth less CO₂ than traditional petrol and diesel cars, based on analysis carried out by a non-profit organization. That differs significantly with lab estimates, which assumed a 75% decrease in emissions.

Analysts examined data from in-vehicle fuel consumption monitors of 800,000 cars sold in the EU 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 3.5 times in 2021.

“Real-world CO2 output are rising, while lab-reported emissions are falling,” said a lead analyst involved in the study. “This gap is growing and creates a serious issue. Consequently, PHEVs emit nearly as heavily as petrol cars.”

Key Factors Driving the Emissions Gap

Researchers linked the majority of the difference to overestimates of the “electric driving share” – the ratio of kilometers driven in electric mode compared to overall distance. The team found that just a quarter of travel was completed in EV mode, whereas official estimates assumed 84%.

Even, when running in EV mode, pollution amounts were well above lab estimates. This happened because electric motors were insufficiently powerful enough to operate independently, resulting to engines using fossil fuels for nearly one-third of the travel completed in electric mode.

Regulatory and Financial Consequences

Based on calculations, the underestimation of PHEV CO2 output allowed several large automaker groups to avoid more than €5bn in fines between 2021 and 2023, by falsely simplifying compliance with European Union average fleet CO₂ targets.

Furthermore, drivers of PHEVs could spend about €500 more per year in operating costs than is estimated under laboratory conditions.

“The bold statements that automakers like to make about their PHEV cars are obviously far from the truth,” stated a transport expert. “Buyers are being misled into thinking that by purchasing a PHEV, they are benefiting the environment and cutting money. Actually, PHEVs are little improved than regular petrol and diesel cars in terms of energy use, CO₂ production, and operating costs.”

Policy Debate and Automotive Pressure

Hybrid vehicles have lately been brought back into policy discussions as automakers have pressed the EU to weaken CO₂ targets. A planned ban on sales of new internal combustion vehicles in 2035 has faced heavy pressure from the car sector and opposition from EU countries with large automotive industries.

Several senior politicians have proposed PHEVs as a potential “flexibility” option to include in the legislation.

One external energy economics specialist, who was unaffiliated with the study, described the analysis a “highly valuable contribution” after a long period in which parts of the automotive industry argued there was too little information to accurately evaluate real-world emissions.

“The results show, beyond any doubt, that the difference between lab and real-world PHEV fuel consumption and CO₂ output is much, much larger than for gasoline or conventional cars,” they stated. “All policy changes concerning PHEVs should be made with utmost caution and in the light of that data.”