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PHEVs release nearly 5x more planet-heating emissions than official figures indicate, according to a recent report.

Widening Gap In Official and Actual CO2 Output

Statistics shows that PHEVs release just one-fifth less CO₂ than conventional petrol and diesel cars, based on analysis carried out by a advocacy group. This differs sharply with lab estimates, which assumed a 75% reduction in emissions.

Researchers examined information from onboard energy use monitors of eight hundred thousand cars registered in Europe between 2021 and 2023. They found that real-world CO₂ emissions from PHEVs in 2023 were 4.9 times higher than official estimates, up from 3.5 times in 2021.

“Actual CO2 output are increasing, while official emissions are decreasing,” said a senior researcher involved in the report. “This discrepancy is growing and creates a significant problem. As a result, PHEVs pollute almost as heavily as petrol cars.”

Primary Factors Driving the Emissions Gap

Analysts linked the majority of the gap to overestimates of the “electric driving share” – the ratio of miles travelled in electric mode relative to overall mileage. They found that only 27% of travel was completed in EV mode, while lab assumptions assumed over four-fifths.

Additionally, when running in EV mode, emission levels were well above official projections. This occurred because electric motors were insufficiently powerful sufficient to function independently, resulting to engines burning fossil fuels for nearly one-third of the travel completed in EV mode.

Regulatory and Financial Consequences

Based on calculations, the underestimation of PHEV CO2 output allowed several large carmaker companies to avoid over €5bn in penalties from 2021 and 2023, by artificially easing compliance with European Union average fleet CO₂ standards.

Furthermore, drivers of PHEVs could pay about €500 extra annually in operating expenses than is assumed under lab tests.

“The strong claims that automakers often promote about their PHEV cars are obviously way off the truth,” stated a automotive analyst. “Consumers are being misled into thinking that by buying a PHEV, they are benefiting the environment and cutting costs. In reality, PHEVs are only slightly better than regular gas and diesel cars in terms of fuel use, CO₂ emissions, and operating costs.”

Political Discussion and Industry Pressure

Hybrid cars have lately been brought back into political debates as automakers have lobbied the EU to relax CO₂ targets. A proposed ban on sales of new internal combustion vehicles in 2035 has faced heavy pressure from the car sector and opposition from EU countries with large automotive manufacturing.

Several senior officials have proposed plug-in hybrids as a potential “flexibility” option to introduce in the regulation.

An independent energy economics specialist, who was unaffiliated with the study, called the analysis a “highly valuable addition” after a long period in which segments of the automotive industry claimed there was too little information to properly assess actual CO2 output.

“These findings demonstrate, without question, that the difference in official and real-world PHEV energy use and CO₂ emissions is significantly larger than for petrol or diesel cars,” they said. “All regulatory changes concerning PHEVs should be made with extreme care and in the light of that evidence.”