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PHEVs produce nearly 5x more global warming pollution than official figures indicate, according to a recent analysis.

Widening Discrepancy In Official and Real-World Emissions

Statistics reveals that PHEVs release only 19% lower CO₂ than traditional gas and diesel vehicles, according to analysis carried out by a advocacy group. This differs sharply with laboratory estimates, which assumed a 75% decrease in emissions.

Researchers examined data from onboard fuel consumption monitors of 800,000 cars registered in Europe between 2021 and 2023. They found that real-world CO₂ emissions from PHEVs in 2023 were nearly five times higher than lab figures, up from 3.5 times in 2021.

“Real-world CO2 output are rising, while official emissions are decreasing,” stated a senior researcher participating in the study. “That gap is widening and creates a serious issue. Consequently, PHEVs emit nearly as heavily as petrol cars.”

Key Factors Driving the Emissions Gap

Researchers attributed the majority of the gap to overestimates of the “utility factor” – the ratio of kilometers travelled in electric power relative to overall mileage. They found that only 27% of travel was done in EV mode, whereas lab estimates assumed 84%.

Additionally, when running in electric mode, pollution amounts were significantly higher than lab estimates. That happened because electric motors were insufficiently powerful enough to operate independently, leading to combustion motors using fossil fuels for almost one-third of the travel covered in EV mode.

Regulatory and Financial Implications

Based on estimates, the underestimation of PHEV emissions allowed four major automaker companies to escape over €5bn in fines between 2021 and 2023, by falsely easing compliance with European Union fleet-average CO₂ targets.

Furthermore, drivers of PHEVs would spend approximately €500 more per year in running expenses than would be assumed under laboratory conditions.

“The bold statements that automakers like to make about their PHEV cars are obviously far from the truth,” stated a transport expert. “Consumers are being duped into thinking that by purchasing a PHEV, they are benefiting the planet and saving costs. Actually, PHEVs are only slightly improved than standard petrol and diesel cars in terms of energy use, CO₂ production, and operating expenses.”

Policy Discussion and Automotive Pressure

Plug-in hybrid vehicles have recently been drawn back into political debates as automakers have lobbied the EU to relax CO₂ targets. A proposed prohibition on sales of new combustion engine cars in 2035 has faced heavy lobbying from the car industry and resistance from member states with significant car manufacturing.

Several senior politicians have proposed PHEVs as a possible “flexibility” solution to introduce in the legislation.

An independent energy economics specialist, who was not involved with the study, called the analysis a “highly valuable addition” after a long period in which parts of the car industry argued there was insufficient information to properly assess actual CO2 output.

“The results show, beyond any doubt, that the gap in official and real-world PHEV energy use and CO₂ emissions is significantly greater than for petrol or conventional vehicles,” the expert stated. “All policy changes concerning PHEVs should be made with extreme caution and considering this evidence.”