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Plug-in hybrid cars emit almost 5x more global warming pollution than official figures show, as per a recent analysis.

Growing Gap In Official and Real-World CO2 Output

Data reveals that PHEVs release just one-fifth lower CO₂ than traditional gas and diesel cars, based on research conducted by a advocacy organization. That differs significantly with lab estimates, which assumed a 75% decrease in pollution.

Researchers examined data from in-vehicle fuel consumption meters of 800,000 cars sold in the EU from 2021 and 2023. They discovered that real-world CO₂ output from PHEVs in 2023 were nearly five times higher than official estimates, increased from 3.5 times in 2021.

“Actual emissions are increasing, while lab-reported emissions are falling,” stated a senior researcher involved in the report. “That discrepancy is growing and poses a significant issue. As a result, PHEVs emit nearly as heavily as petrol vehicles.”

Primary Factors Behind the Emissions Gap

Researchers linked most of the gap to overestimates of the “utility factor” – the percentage of miles driven in battery power compared to overall distance. The team determined that only a quarter of driving was done in EV mode, while lab estimates assumed over four-fifths.

Even, when operating in electric mode, pollution amounts were significantly higher than lab projections. That occurred because EV motors were insufficiently powerful sufficient to operate alone, leading to combustion motors using gasoline for almost a third of the travel covered in EV mode.

Regulatory and Financial Consequences

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

Additionally, owners of PHEVs could spend approximately €500 more per year in running expenses than is assumed under laboratory tests.

“The strong statements that automakers like to make about their PHEV cars are obviously far from the truth,” commented a automotive analyst. “Consumers are being misled into believing that by purchasing a PHEV, they are helping the planet and saving money. In reality, PHEVs are only slightly improved than standard gas and diesel cars in terms of energy consumption, CO₂ production, and operating expenses.”

Policy Discussion and Industry Pressure

Hybrid vehicles have recently been brought back into policy debates as carmakers have pressed the EU to relax CO₂ standards. A proposed prohibition on sales of new internal combustion vehicles in 2035 has faced intense lobbying from the car industry and opposition from EU countries with large automotive industries.

Some high-level officials have proposed PHEVs as a possible “compromise” option to introduce in the regulation.

One external energy policy expert, who was unaffiliated with the research, described the analysis a “very useful addition” after a long period in which segments of the automotive sector argued there was insufficient information to properly evaluate real-world emissions.

“The results demonstrate, without question, that the difference in official and real-world PHEV fuel consumption and CO₂ emissions is significantly larger than for gasoline or conventional cars,” they stated. “All policy changes concerning PHEVs should be implemented with extreme caution and considering that evidence.”