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Plug-in hybrid cars emit almost five times more planet-heating emissions than official data show, as per a new report.

Growing Discrepancy In Lab and Actual CO2 Output

Statistics shows that PHEVs release just one-fifth lower CO₂ than traditional gas and diesel vehicles, based on analysis carried out by a advocacy group. That differs significantly with lab estimates, which assumed a three-quarters decrease in emissions.

Researchers examined information from in-vehicle fuel consumption monitors of 800,000 cars registered in Europe from 2021 and 2023. They found that actual CO₂ emissions from PHEVs in 2023 were nearly five times higher than official figures, increased from 3.5 times in 2021.

“Real-world emissions are rising, while official figures are falling,” stated a lead researcher involved in the study. “That gap is widening and poses a serious issue. Consequently, PHEVs emit almost as much as gasoline cars.”

Key Reasons Driving the Discrepancy

Analysts attributed the majority of the difference to overestimates of the “utility factor” – the ratio of miles driven in battery power relative to total distance. They found that just a quarter of travel was completed in electric mode, whereas official assumptions assumed 84%.

Additionally, when running in electric mode, emission amounts were well above lab estimates. This occurred because EV motors were not strong sufficient to operate independently, leading to engines using gasoline for almost one-third of the distance completed in electric mode.

Regulatory and Financial Implications

According to estimates, the lowballing of PHEV CO2 output enabled several large automaker groups to avoid more than €5bn in penalties from 2021 and 2023, by artificially easing adherence with EU fleet-average CO₂ targets.

Furthermore, owners of PHEVs would pay approximately €500 extra annually in running expenses than would be estimated under lab tests.

“The strong statements that automakers like to make about their plug-in hybrid vehicles are obviously way off the truth,” commented a automotive analyst. “Consumers are being duped into believing that by purchasing a PHEV, they are benefiting the planet and cutting money. Actually, PHEVs are only slightly improved than regular gas and diesel cars in terms of fuel use, CO₂ production, and operating costs.”

Policy Discussion and Industry Pressure

Hybrid vehicles have lately been drawn back into political debates as automakers have lobbied the European Union to relax CO₂ targets. A planned ban on sales of new combustion engine vehicles in 2035 has faced intense lobbying from the car sector and resistance from EU countries with significant car industries.

Several high-level politicians have proposed plug-in hybrids as a possible “compromise” solution to include in the legislation.

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 sector claimed there was insufficient information to accurately assess real-world emissions.

“These findings demonstrate, without question, that the difference between official and actual PHEV energy use and CO₂ output is significantly larger than for gasoline or conventional vehicles,” they stated. “Any policy adjustments concerning PHEVs should be implemented with extreme caution and in the light of that evidence.”