🔗 Share this article

PHEVs release almost 5x more planet-heating pollution than lab-reported data indicate, as per a new analysis.

Growing Discrepancy Between Lab and Actual CO2 Output

Data shows that PHEVs emit only one-fifth lower CO₂ than conventional petrol and diesel cars, based on research conducted by a advocacy organization. That differs sharply with laboratory estimates, which suggested a 75% reduction in pollution.

Analysts studied data from in-vehicle energy use meters of eight hundred thousand vehicles registered in the EU from 2021 and 2023. The team found that actual CO₂ emissions from PHEVs in 2023 were nearly five times higher than lab estimates, increased from 3.5 times in 2021.

“Actual CO2 output are increasing, while lab-reported figures are falling,” said a senior researcher involved in the study. “That discrepancy is widening and creates a serious problem. Consequently, PHEVs pollute almost as heavily as gasoline cars.”

Key Reasons Behind the Emissions Gap

Analysts attributed the majority of the difference to inflated estimates of the “electric driving share” – the ratio of kilometers driven in electric power relative to overall mileage. The team found that only a quarter of travel was done in EV mode, while lab assumptions assumed over four-fifths.

Additionally, when operating in EV mode, emission levels were significantly higher than lab projections. That happened because electric motors were insufficiently powerful sufficient to function independently, resulting to combustion motors burning fossil fuels for nearly one-third of the travel covered in EV mode.

Regulatory and Economic Implications

Based on estimates, the underestimation of PHEV emissions enabled several major carmaker groups to avoid over €5bn in fines between 2021 and 2023, by falsely easing compliance with European Union average fleet CO₂ standards.

Additionally, owners of PHEVs could pay about €500 extra annually in running costs than would be estimated under lab conditions.

“The bold statements that manufacturers like to make about their PHEV vehicles are obviously far from the mark,” commented a automotive expert. “Consumers are being misled into believing that by purchasing a PHEV, they are benefiting the environment and saving money. In reality, PHEVs are only slightly improved than regular gas and diesel cars in terms of fuel consumption, CO₂ emissions, and running costs.”

Policy Discussion and Automotive Pressure

Hybrid cars have lately been brought again into policy discussions as automakers have lobbied the European Union to weaken CO₂ targets. A proposed prohibition on new internal combustion vehicles in 2035 has faced intense lobbying from the car sector and opposition from member states with significant automotive manufacturing.

Some senior politicians have proposed PHEVs as a potential “compromise” option to include in the regulation.

One independent energy policy specialist, who was not involved with the study, described the report a “highly valuable contribution” after a long period in which parts of the automotive sector argued there was insufficient data to properly evaluate actual CO2 output.

“The results demonstrate, beyond any doubt, that the gap between lab and actual PHEV fuel consumption and CO₂ emissions is significantly greater than for gasoline or diesel cars,” the expert said. “All regulatory changes concerning PHEVs should be made with utmost care and in the light of that data.”