Plug-in Hybrid electric Cars Emit Nearly as Heavily as Gasoline Cars, Report Finds

Plug-in hybrid electric vehicles produce nearly 5x greater planet-heating pollution than lab-reported data indicate, according to a new analysis.

Growing Discrepancy In Official and Actual CO2 Output

Data reveals that PHEVs release only one-fifth less CO₂ than conventional petrol and diesel vehicles, according to research carried out by a advocacy organization. This contrasts significantly with laboratory tests, which assumed a 75% decrease in pollution.

Researchers examined data from onboard energy use meters of eight hundred thousand cars registered in the EU between 2021 and 2023. The team found that real-world CO₂ emissions from PHEVs in 2023 were nearly five times greater than official estimates, increased from 3.5 times in 2021.

“Real-world CO2 output are increasing, while lab-reported emissions are decreasing,” stated a senior analyst participating in the study. “This gap is widening and poses a significant problem. As a result, PHEVs pollute nearly as much as gasoline vehicles.”

Primary Factors Driving the Emissions Gap

Analysts attributed the majority of the gap to overestimates of the “electric driving share” – the percentage of kilometers driven in battery power relative to total distance. The team found that only 27% of travel was completed in electric mode, while lab estimates assumed 84%.

Additionally, when running in EV mode, emission amounts were well above lab projections. This occurred because electric motors were not strong sufficient to function independently, leading to combustion motors 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 enabled several large carmaker groups to escape over €5bn in fines between 2021 and 2023, by artificially easing compliance with European Union average fleet CO₂ standards.

Additionally, owners of PHEVs could pay approximately €500 more per year in operating costs than is assumed under lab conditions.

“The bold statements that automakers like to make about their PHEV vehicles are obviously way off the mark,” commented a transport analyst. “Consumers are being duped into thinking that by buying a PHEV, they are benefiting the environment and cutting money. In reality, PHEVs are only slightly better than standard petrol and diesel vehicles in terms of energy consumption, CO₂ emissions, and operating costs.”

Political Debate and Automotive Lobbying

Hybrid vehicles have lately been drawn back into policy discussions as carmakers have pressed the EU to weaken CO₂ targets. A planned ban on sales of new combustion engine vehicles in 2035 has faced intense lobbying from the automotive industry and resistance from member states with large automotive industries.

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

One external energy economics expert, who was not involved with the research, described the report a “highly valuable addition” after years in which segments of the car sector argued there was too little data to accurately assess actual emissions.

“These findings show, without question, that the difference between official and actual PHEV fuel consumption and CO₂ output is significantly larger than for petrol or diesel vehicles,” they stated. “Any policy changes regarding PHEVs should be made with utmost caution and in the light of this data.”