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Plug-in hybrid electric vehicles emit nearly five times more global warming emissions than official figures show, as per a recent report.

Growing Discrepancy Between Lab and Actual CO2 Output

Statistics reveals that PHEVs emit just 19% less CO₂ than traditional gas and diesel cars, according to analysis conducted by a advocacy group. This differs sharply with lab tests, which assumed a 75% decrease in pollution.

Analysts examined data from in-vehicle energy use monitors of eight hundred thousand vehicles registered in the EU from 2021 and 2023. They discovered that actual CO₂ emissions from PHEVs in 2023 were 4.9 times higher than lab estimates, up from three and a half times in 2021.

“Real-world CO2 output are increasing, while official figures are decreasing,” said a lead analyst involved in the report. “That gap is growing and creates a significant issue. As a result, PHEVs pollute nearly as much as petrol vehicles.”

Key Factors Behind the Discrepancy

Researchers linked the majority of the difference to overestimates of the “utility factor” – the percentage of kilometers driven in electric power relative to overall distance. They found that only 27% of driving was done in EV mode, whereas official estimates suggested 84%.

Additionally, when operating in electric mode, emission levels were significantly higher than lab estimates. This happened because EV motors were insufficiently powerful sufficient to operate alone, leading to combustion motors using gasoline for almost a third of the travel completed in electric mode.

Regulatory and Financial Consequences

Based on calculations, the lowballing of PHEV emissions enabled four major carmaker groups to avoid more than €5bn in penalties from 2021 and 2023, by artificially easing compliance with EU average fleet CO₂ standards.

Furthermore, drivers of PHEVs could spend approximately €500 more annually in operating costs than is assumed under laboratory conditions.

“The bold claims that manufacturers like to make about their plug-in hybrid vehicles are clearly far from the mark,” commented a transport analyst. “Buyers are being misled into believing that by buying a PHEV, they are helping the planet and saving money. In reality, PHEVs are only slightly better than regular gas and diesel cars in terms of fuel consumption, CO₂ emissions, and operating costs.”

Political Debate and Industry Pressure

Hybrid vehicles have recently been brought again into policy discussions as automakers have lobbied the European Union to weaken CO₂ targets. A planned prohibition on new combustion engine vehicles in 2035 has faced intense pressure from the automotive industry and opposition from member states with significant car manufacturing.

Several senior politicians have suggested plug-in hybrids as a potential “compromise” solution to include in the legislation.

One external energy economics expert, who was not involved with the study, called the report a “very useful contribution” after years in which parts of the automotive industry claimed there was insufficient information to accurately assess real-world CO2 output.

“These findings demonstrate, beyond any doubt, that the difference between lab and actual PHEV fuel consumption and CO₂ output is significantly larger than for gasoline or diesel vehicles,” the expert stated. “All regulatory adjustments regarding PHEVs should be implemented with utmost care and in the light of that data.”