🔗 Share this article

PHEVs produce nearly five times more planet-heating emissions than lab-reported figures show, according to a new analysis.

Growing Discrepancy Between Official and Actual Emissions

Data shows that PHEVs emit just one-fifth less CO₂ than conventional gas and diesel vehicles, according to research conducted by a non-profit group. That differs sharply with laboratory estimates, which suggested a 75% reduction in pollution.

Analysts studied data from onboard fuel consumption meters of eight hundred thousand cars sold in Europe between 2021 and 2023. The team discovered that actual CO₂ output from PHEVs in 2023 were 4.9 times higher than lab figures, increased from 3.5 times in 2021.

“Actual CO2 output are rising, while lab-reported emissions are falling,” stated a lead analyst participating in the report. “This gap is growing and creates a serious problem. Consequently, PHEVs emit almost as much as petrol vehicles.”

Key Factors Driving the Emissions Gap

Researchers linked most of the gap to overestimates of the “utility factor” – the percentage of miles driven in electric power compared to total distance. They found that only a quarter of travel was completed in EV mode, whereas official estimates assumed over four-fifths.

Additionally, when running in electric mode, pollution levels were well above lab projections. That happened because EV motors were not strong sufficient to operate independently, leading to combustion motors burning fossil fuels for almost a third of the distance covered in electric mode.

Policy and Financial Implications

Based on calculations, the lowballing of PHEV emissions enabled several large automaker companies to escape over €5bn in penalties between 2021 and 2023, by artificially easing adherence with EU fleet-average CO₂ targets.

Additionally, owners of PHEVs would pay about €500 more annually in operating expenses than would be estimated under lab tests.

“The strong claims that automakers like to make about their PHEV vehicles are obviously far from the mark,” stated a automotive expert. “Consumers are being misled into thinking that by buying a PHEV, they are benefiting the planet and saving costs. In reality, PHEVs are little better than standard petrol and diesel vehicles in terms of fuel consumption, CO₂ emissions, and operating expenses.”

Political Discussion and Industry Pressure

Plug-in hybrid vehicles have recently been drawn again into policy discussions as carmakers have pressed the European Union to relax CO₂ standards. A proposed prohibition on sales of new internal combustion vehicles in 2035 has faced intense pressure from the car industry and resistance from EU countries with significant automotive industries.

Some high-level politicians have suggested plug-in hybrids as a potential “flexibility” option to include in the regulation.

An independent energy policy specialist, who was not involved with the study, described the report a “highly valuable contribution” after years in which parts of the automotive sector claimed there was insufficient information to accurately assess real-world CO2 output.

“The results show, beyond any doubt, that the difference in lab and actual PHEV fuel consumption and CO₂ emissions is significantly larger than for gasoline or conventional cars,” they said. “All regulatory adjustments concerning PHEVs should be implemented with extreme care and in the light of this evidence.”