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Plug-in hybrid cars emit nearly five times greater planet-heating pollution than lab-reported figures show, according to a recent analysis.

Growing Discrepancy In Lab and Real-World CO2 Output

Statistics reveals that PHEVs release only 19% lower CO₂ than traditional gas and diesel cars, based on research carried out by a non-profit organization. This contrasts sharply with laboratory estimates, which suggested a three-quarters decrease in emissions.

Analysts studied data from in-vehicle fuel consumption monitors of eight hundred thousand cars sold in Europe from 2021 and 2023. The team found that actual CO₂ emissions from PHEVs in 2023 were 4.9 times greater than lab estimates, increased from three and a half times in 2021.

“Actual emissions are increasing, while official figures are falling,” stated a senior researcher involved in the report. “This discrepancy is widening and poses a serious problem. Consequently, PHEVs pollute nearly as heavily as petrol cars.”

Primary Reasons Behind the Discrepancy

Analysts linked most of the gap to inflated estimates of the “electric driving share” – the percentage of miles travelled in battery power compared to overall mileage. The team found that just a quarter of driving was done in electric mode, while lab estimates assumed 84%.

Even, when running in electric mode, pollution levels were significantly higher than lab estimates. This occurred because electric motors were not strong enough to function independently, resulting to engines using gasoline for nearly one-third of the travel completed in electric mode.

Regulatory and Economic Consequences

According to calculations, the lowballing of PHEV emissions enabled four major automaker companies to avoid more than €5bn in penalties between 2021 and 2023, by falsely easing compliance with EU average fleet CO₂ targets.

Furthermore, owners of PHEVs would pay about €500 more annually in operating costs than would be assumed under lab tests.

“The strong statements that automakers often promote about their PHEV cars are obviously far from the mark,” commented a automotive analyst. “Consumers are being misled into thinking that by purchasing a PHEV, they are benefiting the planet and saving money. Actually, PHEVs are little improved than standard gas and diesel vehicles in terms of fuel use, CO₂ production, and operating expenses.”

Political Discussion and Industry Lobbying

Hybrid cars have recently been drawn back into political discussions as automakers have pressed the European Union to relax CO₂ standards. A proposed ban on new combustion engine cars in 2035 has faced heavy lobbying from the car industry and resistance from EU countries with large automotive manufacturing.

Some high-level officials have suggested plug-in hybrids as a possible “compromise” option to introduce in the regulation.

One independent energy economics specialist, who was not involved with the research, called the report a “highly valuable contribution” after years in which parts of the automotive industry claimed there was insufficient information to accurately evaluate actual CO2 output.

“The results show, without question, that the gap in lab and real-world PHEV fuel consumption and CO₂ output is much, much larger than for petrol or diesel cars,” the expert said. “Any policy changes concerning PHEVs should be implemented with utmost caution and in the light of this evidence.”