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

Plug-in hybrid electric vehicles produce almost five times greater planet-heating pollution than lab-reported data show, according to a recent report.

Widening Gap Between Lab and Real-World CO2 Output

Statistics reveals that PHEVs emit only one-fifth less CO₂ than conventional petrol and diesel vehicles, according to research carried out by a advocacy group. That differs significantly with lab tests, which assumed a 75% reduction in pollution.

Analysts examined data from onboard energy use meters of eight hundred thousand cars registered in the EU from 2021 and 2023. They discovered that actual CO₂ emissions from PHEVs in 2023 were 4.9 times greater than lab estimates, increased from 3.5 times in 2021.

“Actual emissions are increasing, while official emissions are decreasing,” said a senior analyst participating in the report. “This gap is growing and creates a significant problem. Consequently, PHEVs emit almost as much as petrol cars.”

Key Reasons Behind the Discrepancy

Researchers linked the majority of the gap to inflated estimates of the “electric driving share” – the percentage of kilometers travelled in electric mode compared to overall distance. They found that only a quarter of travel was done in electric mode, while lab estimates assumed over four-fifths.

Even, when running in EV mode, pollution amounts were well above official estimates. This occurred because electric motors were insufficiently powerful sufficient to operate alone, resulting to combustion motors burning fossil fuels for nearly one-third of the distance completed in EV mode.

Policy and Financial Consequences

Based on calculations, the lowballing of PHEV CO2 output enabled several large carmaker companies to avoid more than €5bn in fines between 2021 and 2023, by artificially easing compliance with EU fleet-average CO₂ standards.

Additionally, drivers of PHEVs would spend about €500 extra per year in running costs than would be estimated under lab tests.

“The bold statements that automakers often promote about their plug-in hybrid cars are obviously far from the truth,” commented a automotive analyst. “Buyers are being duped into believing that by buying a PHEV, they are benefiting the environment and cutting costs. In reality, PHEVs are little better than standard petrol and diesel cars in terms of fuel consumption, CO₂ emissions, and running costs.”

Political Debate and Industry Lobbying

Plug-in hybrid cars have lately been brought again into policy debates as carmakers have lobbied the EU to weaken CO₂ targets. A planned prohibition on new combustion engine vehicles in 2035 has faced intense pressure from the automotive sector and opposition from member states with large automotive manufacturing.

Several high-level politicians have proposed PHEVs as a possible “flexibility” option to introduce in the legislation.

An external energy policy specialist, who was not involved with the research, described the analysis a “highly valuable addition” after a long period in which segments of the automotive industry claimed there was insufficient information to accurately assess real-world emissions.

“These findings demonstrate, without question, that the difference between official and actual PHEV fuel consumption and CO₂ output is much, much greater than for petrol or diesel vehicles,” the expert said. “All regulatory changes regarding PHEVs should be made with extreme caution and in the light of this data.”