Plug in Hybrid electric Vehicles Pollute Almost as Much as Petrol Vehicles, Report Reveals

PHEVs release almost five times more global warming pollution than official data indicate, according to a new report.

Growing Gap In Official and Real-World Emissions

Statistics shows that PHEVs emit just one-fifth less CO₂ than traditional petrol and diesel cars, according to analysis conducted by a non-profit group. That differs sharply with laboratory estimates, which suggested a 75% reduction in emissions.

Analysts examined information from in-vehicle energy use meters of 800,000 cars registered in the EU from 2021 and 2023. The team discovered that real-world CO₂ emissions from PHEVs in 2023 were 4.9 times greater than official estimates, increased from 3.5 times in 2021.

“Actual CO2 output are rising, while lab-reported emissions are decreasing,” stated a senior analyst participating in the study. “This discrepancy is growing and creates a significant issue. As a result, PHEVs pollute almost as much as petrol cars.”

Primary Reasons Driving the Emissions Gap

Analysts attributed most of the gap to overestimates of the “utility factor” – the percentage of miles driven in battery power relative to overall mileage. The team determined that just 27% of travel was completed in EV mode, whereas official assumptions assumed over four-fifths.

Additionally, when operating in EV mode, pollution levels were well above official projections. That occurred because EV motors were not strong sufficient to function alone, resulting to engines using gasoline for almost a third of the distance completed in electric mode.

Policy and Financial Implications

Based on estimates, the underestimation of PHEV CO2 output enabled several major carmaker companies to avoid over €5bn in penalties between 2021 and 2023, by artificially easing compliance with EU average fleet CO₂ standards.

Furthermore, drivers of PHEVs could pay about €500 extra annually in operating costs than would be assumed under laboratory tests.

“The strong statements that automakers often promote about their PHEV cars are obviously far from the truth,” commented a transport analyst. “Consumers are being duped into thinking that by purchasing a PHEV, they are helping the planet and saving costs. Actually, PHEVs are little better than regular petrol and diesel vehicles in terms of fuel consumption, CO₂ production, and running expenses.”

Policy Debate and Industry Pressure

Hybrid cars have lately been drawn back into political discussions as automakers have pressed the EU to relax CO₂ targets. A planned ban on new combustion engine cars in 2035 has faced intense pressure from the car industry and resistance from EU countries with significant automotive manufacturing.

Some high-level politicians have suggested plug-in hybrids as a potential “compromise” option to include in the legislation.

An independent energy policy expert, who was not involved with the research, called the report a “highly valuable contribution” after years in which parts of the car industry argued there was too little data to properly assess real-world CO2 output.

“The results demonstrate, without question, that the difference in official and real-world PHEV energy use and CO₂ output is significantly larger than for gasoline or conventional cars,” the expert stated. “All regulatory changes regarding PHEVs should be implemented with extreme caution and considering this data.”