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Plug-in hybrid cars release almost five times greater planet-heating pollution than lab-reported figures indicate, as per a recent report.

Growing Discrepancy Between Lab and Real-World CO2 Output

Data reveals that PHEVs emit only one-fifth less CO₂ than traditional gas and diesel vehicles, based on research conducted by a advocacy organization. That contrasts sharply with laboratory estimates, which assumed a 75% decrease in emissions.

Researchers examined information from in-vehicle fuel consumption meters of 800,000 vehicles sold in the EU from 2021 and 2023. The team discovered that actual CO₂ emissions from PHEVs in 2023 were 4.9 times greater than lab figures, increased from three and a half times in 2021.

“Real-world emissions are rising, while official emissions are falling,” stated a lead researcher involved in the study. “This gap is growing and creates a serious problem. Consequently, PHEVs emit nearly as much as gasoline vehicles.”

Key Reasons Driving the Emissions Gap

Analysts attributed most of the difference to overestimates of the “electric driving share” – the ratio of miles travelled in electric power compared to total distance. They determined that just a quarter of travel was done in EV mode, while lab assumptions assumed 84%.

Additionally, when operating in electric mode, pollution levels were well above official projections. That occurred because electric motors were not strong sufficient to operate alone, leading to combustion motors burning fossil fuels for nearly one-third of the distance covered in EV mode.

Regulatory and Financial Implications

Based on calculations, the lowballing of PHEV CO2 output enabled four major automaker groups to escape over €5bn in penalties between 2021 and 2023, by artificially easing adherence with European Union average fleet CO₂ standards.

Additionally, owners of PHEVs could pay approximately €500 more per year in running costs than is estimated under laboratory tests.

“The strong claims that manufacturers often promote about their PHEV cars are obviously far from the truth,” stated a transport expert. “Consumers are being misled into thinking that by purchasing a PHEV, they are benefiting the environment and saving costs. Actually, PHEVs are only slightly improved than regular gas and diesel vehicles in terms of energy use, CO₂ production, and operating expenses.”

Political Discussion and Industry Lobbying

Hybrid cars have recently been brought again into policy discussions as automakers have lobbied the European Union to weaken CO₂ targets. A planned prohibition on sales of new internal combustion cars in 2035 has faced intense lobbying from the automotive industry and opposition from EU countries with significant automotive manufacturing.

Some high-level politicians have proposed PHEVs as a potential “compromise” solution to include in the regulation.

An independent energy policy expert, who was unaffiliated with the study, called the analysis a “very useful contribution” after a long period in which parts of the car sector argued there was insufficient information to properly evaluate real-world CO2 output.

“These findings demonstrate, beyond any doubt, that the difference between official and actual PHEV fuel consumption and CO₂ output is much, much greater than for gasoline or conventional vehicles,” the expert stated. “Any regulatory adjustments regarding PHEVs should be made with utmost care and considering this data.”