Plug-in Hybrid Vehicles Pollute Almost as Much as Petrol Vehicles, Study Reveals

Plug-in hybrid cars produce nearly 5x greater global warming pollution than lab-reported data show, as per a new analysis.

Growing Gap Between Lab and Real-World Emissions

Data shows that PHEVs release just one-fifth lower CO₂ than traditional gas and diesel cars, based on analysis conducted by a advocacy organization. This contrasts significantly with lab tests, which suggested a three-quarters reduction in emissions.

Analysts examined information from in-vehicle fuel consumption monitors of 800,000 cars sold in the EU between 2021 and 2023. They found that real-world CO₂ output from PHEVs in 2023 were nearly five times greater than lab estimates, up from 3.5 times in 2021.

“Actual emissions are increasing, while official figures are falling,” stated a lead researcher involved in the report. “This gap is widening and creates a significant issue. As a result, PHEVs pollute almost as heavily as gasoline cars.”

Key Reasons Driving the Discrepancy

Researchers attributed the majority of the gap to overestimates of the “electric driving share” – the percentage of kilometers travelled in battery mode compared to total distance. They determined that just a quarter of travel was completed in electric mode, while official estimates assumed 84%.

Even, when running in EV mode, pollution amounts were significantly higher than lab projections. This occurred because EV motors were insufficiently powerful enough to function alone, leading to combustion motors using fossil fuels for almost one-third of the distance completed in electric mode.

Regulatory and Financial Implications

According to estimates, the underestimation of PHEV CO2 output enabled several major automaker groups to escape over €5bn in penalties between 2021 and 2023, by artificially simplifying adherence with European Union average fleet CO₂ standards.

Additionally, owners of PHEVs could pay approximately €500 extra per year in operating expenses than is assumed under lab tests.

“The bold claims that manufacturers like to make about their PHEV cars are obviously far from the mark,” commented a automotive expert. “Buyers are being misled into believing that by purchasing a PHEV, they are benefiting the environment and saving money. In reality, PHEVs are little improved than standard gas and diesel cars in terms of energy use, CO₂ production, and running costs.”

Political Debate and Industry Pressure

Plug-in hybrid cars have lately been brought again into policy discussions as automakers have pressed the European Union to relax CO₂ standards. A planned prohibition on sales of new combustion engine cars in 2035 has faced intense pressure from the automotive sector and opposition from member states with large car industries.

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

An independent energy economics expert, who was not involved with the research, called the analysis a “highly valuable contribution” after years in which segments of the car industry argued there was insufficient data to properly evaluate actual CO2 output.

“The results demonstrate, without question, that the difference in lab and actual PHEV energy use and CO₂ emissions is much, much greater than for gasoline or conventional cars,” they said. “All regulatory changes regarding PHEVs should be implemented with utmost care and considering this evidence.”