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Plug-in hybrid electric vehicles emit nearly 5x greater global warming pollution than lab-reported figures show, as per a recent report.

Widening Discrepancy In Official and Actual CO2 Output

Statistics reveals that PHEVs emit only one-fifth lower CO₂ than conventional petrol and diesel vehicles, based on analysis conducted by a advocacy group. That contrasts significantly with lab tests, which assumed a 75% reduction in pollution.

Analysts examined data from in-vehicle energy use meters of 800,000 vehicles sold in the EU between 2021 and 2023. They discovered that actual CO₂ emissions from PHEVs in 2023 were nearly five times greater than lab estimates, increased from 3.5 times in 2021.

“Actual emissions are increasing, while official figures are falling,” said a senior analyst participating in the report. “This gap is growing and creates a significant problem. Consequently, PHEVs pollute nearly as heavily as petrol cars.”

Primary Factors Driving the Discrepancy

Researchers linked the majority of the difference to overestimates of the “utility factor” – the ratio of kilometers driven in electric power relative to overall distance. The team found that only 27% of travel was completed in EV mode, while official assumptions assumed 84%.

Additionally, when running in electric mode, emission levels were significantly higher than official estimates. This happened because EV motors were not strong enough to function independently, leading to engines burning gasoline for almost a third of the travel completed in EV mode.

Regulatory and Economic Implications

According to estimates, the underestimation of PHEV emissions allowed several major automaker companies to escape more than €5bn in fines from 2021 and 2023, by falsely easing compliance with EU fleet-average CO₂ targets.

Furthermore, owners of PHEVs could spend about €500 more per year in operating expenses than is assumed under laboratory tests.

“The strong statements that manufacturers like to make about their PHEV cars are clearly way off the truth,” stated a transport analyst. “Buyers are being misled into thinking that by buying a PHEV, they are benefiting the planet and cutting money. Actually, PHEVs are only slightly improved than standard gas and diesel cars in terms of fuel use, CO₂ production, and operating costs.”

Political Debate and Automotive Pressure

Hybrid cars have lately been drawn back into policy debates as carmakers have pressed the European Union to weaken CO₂ standards. A planned ban on sales of new combustion engine cars in 2035 has faced heavy lobbying from the car industry and opposition from EU countries with large car industries.

Some senior officials have proposed PHEVs as a potential “compromise” solution to include in the legislation.

An independent energy economics specialist, who was not involved with the study, called the report a “highly valuable contribution” after years in which parts of the car industry argued there was insufficient information to properly assess real-world CO2 output.

“These findings demonstrate, beyond any doubt, that the gap between official and real-world PHEV fuel consumption and CO₂ output is significantly greater than for gasoline or conventional cars,” the expert said. “All policy changes regarding PHEVs should be implemented with utmost care and in the light of this data.”