Plug-in Hybrid Cars Emit Nearly as Much as Gasoline Vehicles, Report Reveals

PHEVs emit almost 5x greater global warming pollution than lab-reported figures show, according to a recent report.

Widening Gap Between Official and Real-World Emissions

Statistics reveals that PHEVs release just 19% lower CO₂ than conventional gas and diesel cars, according to analysis conducted by a non-profit organization. This differs significantly with laboratory tests, which suggested a three-quarters decrease in pollution.

Researchers studied data from in-vehicle energy use meters of 800,000 vehicles registered in Europe between 2021 and 2023. The team discovered that real-world CO₂ emissions from PHEVs in 2023 were 4.9 times greater than official estimates, increased from three and a half times in 2021.

“Actual emissions are rising, while lab-reported figures are decreasing,” said a senior analyst participating in the study. “This discrepancy is growing and creates a significant issue. Consequently, PHEVs emit almost as much as gasoline vehicles.”

Primary Factors Driving the Discrepancy

Researchers linked most of the difference to inflated estimates of the “utility factor” – the ratio of miles travelled in electric power compared to overall distance. The team found that only a quarter of travel was completed in EV mode, while lab assumptions assumed 84%.

Additionally, when running in EV mode, emission levels were well above lab projections. That happened because EV motors were insufficiently powerful enough to operate alone, resulting to engines burning fossil fuels for nearly one-third of the distance completed in electric mode.

Policy and Economic Consequences

According to calculations, the lowballing of PHEV emissions allowed several large automaker companies to avoid over €5bn in fines from 2021 and 2023, by falsely simplifying adherence with European Union fleet-average CO₂ standards.

Furthermore, owners of PHEVs could pay approximately €500 more per year in running expenses than is estimated under lab tests.

“The strong statements that manufacturers often promote about their PHEV cars are clearly way off the mark,” commented a automotive analyst. “Buyers are being duped into believing that by purchasing a PHEV, they are helping the planet and cutting costs. In reality, PHEVs are little better than regular gas and diesel vehicles in terms of fuel use, CO₂ emissions, and running costs.”

Political Discussion and Industry Pressure

Hybrid cars have recently been brought back into policy debates as carmakers have pressed the European Union to weaken CO₂ targets. A proposed prohibition on new internal combustion vehicles in 2035 has faced heavy lobbying from the automotive sector and resistance from EU countries with large car industries.

Some high-level politicians have proposed PHEVs as a potential “compromise” solution to include in the legislation.

One external energy economics specialist, who was unaffiliated with the research, called the analysis a “very useful contribution” after a long period in which parts of the car sector argued there was insufficient data to accurately assess actual emissions.

“The results show, without question, that the gap in official and actual PHEV fuel consumption and CO₂ output is much, much greater than for gasoline or conventional cars,” they stated. “All regulatory adjustments concerning PHEVs should be made with utmost care and considering that evidence.”